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Vaillant Boilers Reviews: Best Vaillant Combi Prices for 2024

Vaillant boilers are manufactured by the renowned heating and cooling company, The Vaillant Group. Vaillant boilers’ manufacturer is one of the largest heating and cooling companies in Europe and the United Kingdom. Johann Vaillant first established Vaillant in 1874, and in 1894, he patented a unique “closed-system” gas-fired boiler that revolutionised the heating industry. Nowadays, Vaillant continue to solidify themselves as leaders in the heating industry as they develop and distribute powerful, sleek, eco-friendly boiler models. The Vaillant Group is still family-owned today, and it’s headquartered in Remscheid, North Rhine-Westphalia. Vaillant’s UK headquarters are located in Belper, Derbyshire.

Vaillant boilers
Vaillant boilers have a high-quality build that comes with a high price tag

Vaillant boilers offer three main advantages. Firstly, Vaillant boilers are constructed with quality materials that allow the boilers to endure the strain associated with constant heating and cooling cycles without developing major faults for years. Secondly, Vaillant boilers offer superior customer support, which has earned them largely positive reviews from thousands of users on TrustPilot and elsewhere. Thirdly, Vaillant boilers are equipped with advanced technologies that help avert breakdowns and minimise downtime during bouts of extremely cold weather.

However, there are two main disadvantages to Vaillant boilers. Firstly, Vaillant boilers are not as energy efficient as competitor boilers. Secondly, Vaillant boilers command some of the highest prices among all premium UK boiler manufacturers.

Vaillant boilers’ price ranges between £700 and £2,800. However, this price does not include installation. Generally, installation costs around £800-£1,500 on top of boiler-only costs.

Vaillant manufactures five combi boilers. These are the Vaillant ecoFIT Pure, the ecoTEC Pro, the ecoTEC Plus Comb, the ecoTEC Plus Combi Store, and the ecoTEC Exclusive Green IQ Combi.

Below is an in-depth summary of Vaillant boilers’ prices, ranges, pros, cons, common faults, internal components, and alternative boiler brands.

What is the price range for Vaillant boilers?

The price range for Vaillant boilers is between £730 and £1,950, not including installation costs, which generally add between £800-£1,500 on top of boiler-only costs. Vaillant boilers tend to cost more than other brands because of the brand’s household name status, innovative features, smart technology, and high durability.

Below are the four factors that affect the price of Vaillant boilers.

  • Boiler type: The boiler type impacts how much a Vaillant boiler costs. Typically, system Vaillant boilers cost the most, heat-only boilers cost the least, and combination boilers sit in the middle of the Vaillant boiler price range. Combi and system boilers of any manufacturer tend to cost more because they’re usually in higher demand and have more internal components than their heat-only counterparts.
  • Boiler model: The model you choose affects how much you pay for your new Vaillant boiler. For example, the Vaillant ecoTEC 48kW and 64W system boilers cost the most at roughly £2,200 and £2,800 before installation, respectively. The ecoTEC 486kW and 64W are the most expensive in the Vaillant range because it has all the bells and whistles, including a stainless steel heat exchanger, a mobile-optimised thermostat, and a slimmer body. The stainless steel heat exchanger translates into better durability, the mobile-optimised thermostat means optimal convenience for homeowners, whilst the slim build makes it easy to fit the boiler into tight spaces. These features ultimately drive up the cost of the boiler.
  • Boiler kW size: Heating and hot water output affect the cost of a Vaillant boiler. Typically, boilers with a larger heating and capacity cost more than their lower-output counterparts. For example, the ecoTEC Pro 28kW costs roughly £1,150, whilst the slightly more powerful 30kW version costs about one hundred pounds more, at £1,250 before installation.
  • Boiler warranty: The warranty affects the price of a Vaillant boiler. Vaillant offers boiler warranties that span between 2 and 10 years depending on the model. For example, the ecoTEC Pro 24, ecoTEC Pro 28, and ecoTEC Pro 30 models come with 6-year warranties and cost £1,150-£1,350. Meanwhile, the ecoTEC Plus 832, ecoTEC Plus 835, ecoTEC Plus 618, and ecoTEC Plus 418 come with 8-year warranties and cost £1,300-£1,600 without installation.

The infographic below provides an overview of Vaillant combi, system, and regular boiler prices.

Vaillant boilers prices
Vaillant boilers’ price ranges for combi, system, and regular boilers

Below is a chart that marks ratings of The Vaillant Group on a scale of 1 to 5.

Vaillant Boilers
Vaillant Boiler Specs Rating – 4.2/5.0
Price and performance efficiency 3.0
Design 5.0
Customer service 4.0
Safety 5.0
Warranty duration 4.0

The Vaillant Group scores high in design, customer service, and safety, but we believe Vaillant falls short when it comes to performance, efficiency, and warranties.

How do Vaillant boilers work?

Vaillant boilers work the same way all residential heating boilers do: they generate heat and transfer it to central and domestic heating water. However, the operation of Vaillant boilers differs depending on the boiler type and fuel it uses.

Vaillant boilers come in combination (combi), system, and heat-only boiler types. Combi boilers heat both a home’s domestic water and radiators with one, compact unit, making them economical and space-saving. However, combi boilers struggle to produce vast amounts of domestic hot water at once since they don’t have backup hot water storage and rely solely on mains pressure. Furthermore, combis cannot heat water and the home’s radiators at the same time. For example, if a combi boiler is in the middle of heating water for the home’s radiators and someone turns on the shower, the combi shifts gears and only heats domestic water, allowing the radiators to cool off temporarily. Combis require strong water pressure from the mains to meet high hot water demand, so consider another boiler type if you have a large home or your family uses lots of hot water at the same time.

Vaillant system boilers work by heating the radiator water via their heat exchanger, and then running that heating water through the coil inside the domestic hot water cylinder. The coil allows the tap water inside the cylinder to absorb heat and reach the required temperature of 60C or more. System boilers supply more water at once because they operate with a hot water cylinder. The tanks that integrate with system boilers have an average hot water storage capacity of 300 litres, but some models can be as large as 500 litres. This ability to store hot water allows system boilers to provide a constant supply of hot water. Thus, system boilers are excellent choices for those living in large properties or for families with multiple generations living under one roof. However, system boilers take up much more space due to the associated components, such as the hot water cylinder and the additional pipework. More components mean more maintenance requirements, which becomes expensive toward the end of a system boiler’s lifespan. Lastly, system boilers present a higher upfront cost than other boiler types.

The third boiler type available from Vaillant is the heat-only boiler. These Vaillant boilers operate like a system boiler except the water supply comes from two tanks: one tank for domestic hot water and one tank to feed the central heating system. Heat-only boilers are a smart option for those who live in homes with low water pressure since heat-only boilers work on a gravity-fed pressure system. However, heat-only boilers require a vast amount of space due to the need for a hot water cylinder and two water storage tanks.

Vaillant boilers are available as natural gas, LPG, and electric models. A gas-fired Vaillant boiler works by burning natural gas inside its burner. The boilers’ heat exchanger then transfers the heat to water that circulates through the home’s radiators and separately heats water that flows to the taps and showers. Gas-fired boilers are ideal for homes on the nation’s gas grid, as they provide fast, consistent heating, and generally come with the longest warranties due to their high reliability. Liquefied Petroleum Gas (LPG) Vaillant boilers work exactly like their gas counterparts, except they burn LPG to produce heat. LPG boilers operate off the grid, which makes them appealing to homeowners in rural areas. LPG boilers have high installation costs and require a lot of space for fuel storage. Electric Vaillant boilers operate by using electricity to generate heat. The generated heat transfers to central heating and domestic hot water. Electric Vaillant boilers are quieter than their gas counterparts, have zero risk of producing carbon monoxide, and are nearly 100% efficient. However, electric boilers are expensive and struggle to heat larger homes.

What kind of fuel does your boiler use?

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What are the types of Vaillant boilers?

There are three Vaillant boiler types: combination boilers, system boilers, and heat-only boilers (also known as “regular,” “conventional,” “traditional,” and “open-vent” boilers). The list below provides an overview of the three types of boilers manufactured by Vaillant.

  • Vaillant combi boilers: Vaillant combis work by heating water on-demand rather than keeping water hot inside a cylinder. Combi boilers perform two actions: they heat the home’s tap water and provide central heating. These boilers connect directly to water mains and only heat domestic water when homeowners turn on the tap or shower. Heating water on demand means combi boilers don’t burn fuel to maintain a high temperature inside a hot water cylinder. Additionally, Vaillant combis require much less space than system or regular boilers because they’re not connected to water storage tanks. However, combi boilers struggle to heat larger homes with multiple water access points. For example, combi boilers will have difficulty producing enough hot water if a shower and a kitchen tap are in use at the same time. Vaillant produces five combi ranges, which range from £850 to £1,950 without installation.
  • Vaillant system boilers: System boilers (sometimes referred to as “sealed system boilers”) are boilers that require a water cylinder to store hot water. System boilers’ ability to maintain a large volume of water hot makes them a strong choice for those who live in larger homes that have multiple bathrooms or homes with many people requiring the use of hot water at once. System boiler setups take up more room than combi boilers because of the need to have a hot water cylinder. However, system boilers are more compact than regular boilers because they do not require cold water storage tanks. Vaillant system boilers are compatible with immersion heaters. These are electric water heaters that are installed inside the hot water cylinder. If the gas boiler breaks down, the owner can turn on the immersion heater and thus maintain a supply of domestic hot water. Vaillant system boilers come in five ranges and cost between £800 and £2,800, excluding installation.
  • Vaillant heat-only boilers: Vaillant heat-only boilers heat water for the central heating system, and indirectly supply heat to the domestic hot water cylinder. Heat-only boilers additionally rely on two storage tanks, one of which supplies domestic water to the hot water cylinder, whilst the other maintains pressure in the heating system. As a result, Vaillant heat-only boilers do require a considerable amount of space, making them a far more suitable option for larger houses than small apartments. However, regular boilers from Vaillant are able to supply larger volumes of hot water than combis, so they’re more appropriate for households that consume lots of hot water. Vaillant heat-only boilers cost between £700 and £1550, excluding installation.

The three Vaillant boiler types differ in three key ways. First Vaillant boiler types differ in terms of parts. A combi has two heat exchangers, whereas system and regular boilers only operate with one. Combi boilers additionally have an integral pump that circulates the central heating water, while system and heat-only boilers generally have an external pump. Combi boilers have a diverter valve, which allows them to switch between heating and hot water modes, whilst other boiler types work with a similar valve that’s fitted externally to the heating pipework. System and combi boilers have an expansion vessel that helps relieve pressure. For example, regular boilers relieve pressure by allowing excess water to come back up to the feed and expansion tank. System and combi boilers differ by cylinders and water storage tanks. A system boiler uses a cylinder or water storage tank to store hot water and then disperses the hot water into the taps as needed. Meanwhile, combis heat water on demand and do not require cylinders or storage tanks to store hot water. Secondly, Vaillaint boiler types differ in price. System boilers are the most expensive Vaillant boiler type. Regular boilers are the second most expensive type whilst combis are the least expensive. Thirdly, Vaillant boiler types differ in safety. All three boiler types are generally safe, but they all have inherent safety risks, such as gas leaks, carbon monoxide leaks (if the fan, flue, or PCB components are not working properly), or a risk of explosion if pressure relief mechanisms fail and the boiler does not shut down in response. One potential safety issue that occurs with system and regular boilers, but not with combis, is the presence of Legionella bacteria in the domestic hot water. This bacteria may become present in the hot water cylinder if the boiler malfunctions and fails to maintain a temperature at or above 60°C. Combis do not have this hazard because they get water from the mains, and the bacteria generally thrive in a stagnant environment, such as a tank.

What is the Vaillant combi boiler price range?

The table below provides an overview of the Vaillant combi boiler type price range.

Vaillant Boiler Model Heating kW Consumption Hot water kW Consumption Warranty Duration Boiler Price Range Installation Cost
Vaillant ecoFIT Pure Combi 19.1kW – 35kW 25-35 kW 7 years £850 – £1,150 £800-£1,500
Vaillant ecoTEC Pro Combi 24.8kW – 25.7 kW 24-30 kW 6 years £900 – £1,850 £800-£1,500
Vaillant ecoTEC Plus Combi 20.4kW – 30.1kW 25 – 38 kW 6 years £1,100 – £1,500 £800-£1,500
Vaillant ecoTEC Exclusive with Green iQ Combi 26.4kW – 36kW 35 – 43 kW 6 years £1,400 – £1,950 £800-£1,500
*10-year extended warranty available
What is the Vaillant system boiler price range?

The table below provides an overview of the Vaillant system boiler type price range.

Vaillant Boiler Model kW Consumption Warranty Duration Boiler Price Range Installation Cost
Vaillant ecoTEC Plus System 12 – 37 kW 6 years £800 – £1,300 £800-£1,500
Vaillant ecoFIT Pure System 12 – 30 kW 7 years £850 – £1,200 £800-£1,500
Vaillant ecoTEC Exclusive with Green iQ System 27 kW 6 years £1,200-£1,300 £800-£1,500
Vaillant ecoTEC Plus 48kW & 64kW System 48 – 64 kW 6 years £2,100 – £2,500 £800-£1,500
Vaillant ecoTEC 46kW & 65kW System 46 -65 kW 6 years £2,100 – £2,800 £800-£1,500
*10-year extended warranty available
What is the Vaillant regular boiler price range?

The table below provides an overview of the Vaillant regular boiler type price range.

Vaillant Boiler Model kW Consumption Warranty Duration Boiler Price Range Installation Cost
Vaillant ecoFIT Pure Regular 12 – 35 kW 7 years £700 – £1,500 £800-£1,500
Vaillant ecoTEC Plus Regular 12 – 35 kW 6 years £700 – £1,600 £800-£1,500
*10-year extended warranty available

Keep in mind that the Vaillant boiler prices and installation costs provided in the tables above are only estimates that may change based on your geographic location, heating system setup, and whom you choose as the boiler fitter. You’re able to get an accurate, fixed-price quote for a new Vaillant your screen now by filling out Heatable’s anonymous boiler questionnaire. Heatable are an online boiler installer operating across the UK, and they typically offer attractive deals on boiler installations and financing.

Does a Vaillant boiler heat a home quickly?

All modern boilers heat homes quickly, including Vaillant. How quickly a Vaillant boiler heats a home depends on three factors listed below.

  • Boiler size: Boilers that have the right heating capacity for the home they serve are able to heat a home at an approximate rate of 1 degree Celsius per hour. Undersized boilers take much longer to get the home to the desired indoor temperatures. Conversely, oversized boilers can heat the space quickly but consume too much gas in the process, which will result in a spike in utility bills.
  • Quality of the central heating system: Older systems with clogged or inefficient radiators may take longer to heat up. Conversely, Thermostatic Radiator Valves (known as TRVs) and zoned heat allow you to heat specific areas of the home faster. TRVs are small mechanisms that attach directly to radiators, which allow you to control the temperatures of specific rooms since they independently regulate the room’s radiator. TRVs enable boilers to heat a specific part of the home quickly instead of deploying and dispersing all of the heat the boiler generates to different rooms at the same time, thus slowly raising the indoor air temperature.
  • Quality of insulation: Older, poorly insulated homes take far longer to heat up because heat escapes quickly through the exterior walls, no matter how much power the boiler produces. Many homes in the UK have poor insulation, which means hot air escapes while outdoor cold air seeps in. Thus, the quality of your home’s insulation greatly impacts how quickly your boiler can heat and maintain heat in the home.

Our experts at HeatingForce recommend getting your Vaillant boiler properly sized to ensure that your home heats fast.

Is a Vaillant boiler good for the United Kingdom’s winter conditions?

Yes, Vaillant boilers are good for the United Kingdom’s winter conditions for two key reasons. Firstly, select Vaillant boilers have frost protection. Any boiler risks freezing over and shutting down when outdoor temperatures dip below freezing. Select Vaillant models like the ecoTEC Plus have frost protection, which means that the boiler self-protects against this threat by deploying warm water through the pipes even when not requested by the homeowner. The circulation of warm water maintains warmer temperatures in the pipes and prevents a freeze from occurring. As a result, homeowners are much more protected from mid-winter breakdowns. Secondly, Vaillant boilers meet modern efficiency standards. Frigid temps mean that the boiler has to work harder to keep the home warm, so boiler efficiency is an important factor to consider on the colder UK winter days. Vaillant boilers meet modern efficiency standards, although they’re not as efficient as Viessmann or Worcester Bosch. On average, Vaillant boilers are 90% efficient, so for each pound you spend on winter heating, 90 pence gets converted into heat. In contrast, inefficient boilers may waste as much as 30 pence per every pound spent on heat during the winter time.

What are the advantages of Vaillant boilers?

Below are the five advantages of Vaillant boilers.

  • Use of high-quality materials: Vaillant boilers comprise stainless steel heat exchangers, black anodized aluminium structures, copper-aluminium absorber coating, and dark laminated glass on select models. These materials improve the boilers’ reliability and durability.
  • Provide superior customer support and service: Vaillant boasts over 140 years in business, and the company has gotten so far in part due to their superior customer support and service. The Vaillant Group has received over 19,000 reviews on Trustpilot, and many of them are positive and speak to the customer service team. For example, customers speak to how prompt and professional the customer service team is. Reviews on Trustpilot cite Vaillants’ friendly, and professional responses. Homeowners praise Vaillants’ clean, orderly technicians who conduct their work quickly and who clean up their trash with them. Vaillant has several customer service options, including telephone lines, online chat, and email. Their positive reviews instil great trust in homeowners and buyers.
  • Prevent breakdowns using advanced technologies: The ecoTEC plus 80, 100 and 120, and the ecoTEC pro boilers employ a built-in frost protection device that protects the boiler from freezing. The mechanism works by activating the boiler if the water temperature gets close enough to the freezing mark. The mechanism uses a sensor to check the temperature periodically, thus determining whether to continue warming the system or shut off the boiler.
  • Come with competitive warranties: Vaillant warranty terms last up to 10 years if you pay for the extension, and cover the cost of parts and labour for repairs for faulty components. A 10-year warranty is an excellent warranty length, as it means Vaillant expects your boiler to last at least a decade without developing major faults. Other manufacturer warranties have warranties of 5 or even 2 years, which means you’re on the hook for costly boiler repairs if the boiler starts malfunctioning after less than half a decade of service. Vaillant warranty covers boiler repairs up to £1,500 and replacement up to £750. However, homeowners must be aware that only genuine Vaillant parts may be used for repairs to count toward the warranty.
  • Offer eco-friendly heating: Vaillant boilers are environmentally friendly and boast higher efficiency scores than many other boiler brands on the market. Vaillant’s products vary by exact efficiency rating, but top models like the ecoTEC boast a 94% efficiency. These systems have such high efficiency due in part to systems like a new intelligent combustion technology that automatically adapts fluctuating gas qualities. High efficiencies like a 94% rating mean only 6% of energy is lost during the production and distribution process.

How is the energy consumption of Vaillant boilers?

The energy consumption of Vaillant boilers is on par with that of other boiler brands. However, the energy consumption differs between electricity and gas in Vaillant boilers, both of which are used to power the boiler’s essential functions. Electricity powers the boiler’s components that are responsible for control and communications, such as the PCB. Meanwhile, gas powers the boiler’s burner, which produces heat and ultimately raises water temperature. Vaillant combi boilers’ gas consumption differs between the combis’ two separate functions, as these boilers use gas to heat domestic and heating water separately.

The electric consumption of Vaillant boilers is readily available in the installation instructions of most models. However, finding out the gas consumption requires the use of a formula that derives the value based on the stated output and efficiency ratings for hot water and heat. We’re able to follow the steps below to calculate the energy consumption of a Vaillant boiler.

  1. Determine the heating and hot water output: The heating output for a given Vaillant boiler model is given in kilowatts (kW) on the manufacturer’s brochure.
  2. Find the boiler heating and hot water efficiency: Vaillant boiler efficiency is often given as a percentage in the boiler description or the manufacturer’s brochure. For example, an efficiency of 90% indicates that 90% of the energy in the fuel goes into heating the water, while the remaining 10% is lost with the flue gases.
  3. Calculate the fuel energy input: Divide the heating output by the efficiency (expressed as a decimal) to find the energy input from the fuel.

Below is an example of the calculation described above being used to determine the fuel consumption of the Vaillant ecoTEC Pro 28 combi.

Vaillant ecoTEC Pro 28 central heating and hot water capacity and efficiency:

  • ecoTEC Pro 28 central heating output: 24.8kW
  • 28 hot water output: 28kW
  • 28 heating efficiency: 94%
  • 28 hot water efficiency: 94%

Vaillant ecoTEC Pro 28 central heating gas consumption per hour:

24.8 / 0.94 = 26.38kW

The formula above shows that a Vaillant ecoTEC Pro 28 combi consumes roughly 26.38kW of natural gas per hour of operation at its peak central heating output.

Vaillant ecoTEC Pro 28 hot water gas consumption per hour:

28k / 0.94 = 29.79kW

A Vaillant ecoTEC Pro 28 combi requires approximately 29.79kW of natural gas to heat domestic hot water for an hour at its maximum output.

The energy consumption of all available Vaillant boiler models is summarised in the table below.

Vaillant boiler model Approximate electricity consumption per hour (operating/standby) Approximate natural gas consumption per hour for heating Approximate natural gas consumption per hour for hot water
Vaillant ecoFIT Pure Combi 25 87W / 2W 25.5kW 25.71kW
Vaillant ecoFIT Pure Combi 30 87W / 2W 25.91kW 30.61kW
Vaillant ecoFIT Pure Combi 35 98W / 3W 25.75kW 35.35kW
Vaillant ecoTEC Pro Combi 24 50W / 2W 23.46kW 24.18kW
Vaillant ecoTEC Pro Combi 28 80W / 2W 24.48kW 27.55kW
Vaillant ecoTEC Pro Combi 30 80W / 2W 27.41kW 33.70kW
Vaillant ecoTEC Plus Combi 825 65W / 2W 21.61kW 29kW
Vaillant ecoTEC Plus Combi 832 85W / 2W 27.32kW 35.61kW
Vaillant ecoTEC Plus Combi 835 90W / 2W 34.04kW 39.19kW
Vaillant ecoTEC Plus Combi 838 120W / 2W 32.02kW 43.33kW
Vaillant ecoTEC Exclusive with Green iQ Combi 627 62W / 1.9W 26.27kW 31.91kW
Vaillant ecoTEC Exclusive with Green iQ Combi 835 79W / 1.9W 27.64kW 39.66kW
Vaillant ecoTEC Exclusive with Green iQ Combi 843 78W / 1.9W 37.07kW 48.76kW
Vaillant ecoTEC Plus System 48kW 162W / 1.8W 45.36W n/a
Vaillant ecoTEC Plus System 64kW 250W / 1.8W 60.20W n/a
Vaillant ecoFIT Pure System 625 87W / 2W 25.91W 30.61W
Vaillant ecoFIT Pure System 630 104W / 2W 30.80W 35.35W
Vaillant ecoTEC Exclusive with Green iQ System 62W / 1.9W 27.65W 33.59W
Vaillant ecoTEC Plus 48kW System 162W / 1.8W 45.46kW n/a
Vaillant ecoTEC Plus 64kW System 250W / 1.8W 59.89kW n/a
Vaillant ecoTEC 46kW System n/a 46.03kW n/a
Vaillant ecoTEC 65kW System n/a 66.70kW n/a
Vaillant ecoFIT Pure 412 Regular 23W / 2W 12.42kW 15.15kW
Vaillant ecoFIT Pure 415 Regular 29W / 2W 15.51kW 18.36kW
Vaillant ecoFIT Pure 418 Regular 34W / 2W 18.67W 25.71W
Vaillant ecoFIT Pure 425 Regular 35W / 2W 25.91kW 30.61kW
Vaillant ecoFIT Pure 430 Regular 44W / 2W 30.80W 35.35W
Vaillant ecoFIT Pure 435 Regular 50W / 2W 35.87kW 36.08kW

Do Vaillant boilers give a signal for fuel wastage?

Vaillant boilers do not have a specific signal for fuel wastage. However, running your Vaillant in the Comfort Mode forces the boiler to consume more fuel than necessary, as it fires up periodically to keep a small store of heated water ready for immediate use. The boiler continues to fire up even if you’re not turning the taps on for hours, thus wasting fuel.

What is the estimated lifespan for a Vaillant boiler?

The estimated lifespan for a Vaillant boiler is between 10 and 15 years, which is common among premium boiler brands. Homeowners may extend their boilers’ lifespan if they perform annual boiler service and maintenance, which helps keep the internal components in good working order while identifying faults early.

What are the disadvantages of Vaillant boilers?

Below are the two key disadvantages of Vaillant boilers.

  • Command a high price: Vaillant boilers have steep price tags. Their lowest prices tend to be in the ballpark of many companies’ highest pricing tier.
  • Offer subpar-to-average efficiency: At one point, Vaillant boilers were indeed more efficient than their competitors. Nowadays, competitor boiler companies release products with boilers up to 97% efficiency, whereas Vaillant continues to release boilers with an average efficiency of 92%.

Does the Vaillant boiler vibrate while working?

Yes, Vaillant boilers occasionally vibrate while working. Intermittent vibrations are especially common in the Vaillant ecoTEC plus 438 boilers. These vibrations are a drawback to the Vaillant boilers as they become grating and annoying after a while, especially if the boiler is in a common living area rather than in a utility room or a cupboard.

The following are the two common reasons Vaillant boilers vibrate.

  • Pump issue: The circulator pump may be working properly either due to a fault or an incorrect speed setting. A pump that’s not functioning properly may cause a Vaillant boiler to produce a vibrating noise.
  • System blockage: Heating sludge and limescale often accumulate inside the boiler and heating system, and the debris accumulation disrupts water circulation. The boiler might produce vibrations when the water isn’t able to flow smoothly through the system.

Do Vaillant boilers have any safety concerns?

No, Vaillant boilers do not have any safety concerns. However, concerns exist with gas boilers in general. For example, homeowners should be aware that it’s possible for carbon monoxide to seep into the house from the boiler if the fan or flue is not functioning properly and the boiler does not lock out in response. Gas leaks are additionally possible in boilers with malfunctioning gas valves or severe wear and tear. Regular boiler service and maintenance are crucial in identifying and preventing these safety concerns.

What are the most common problems of Vaillant boilers?

Below are the eight most common problems of Vaillant boilers.

  • Leaks: Some boiler leaks may be visible, whilst others manifest in low pressure. A pressure reading below 1 bar on a Vaillant is a likely indicator of a leak somewhere in the system. Boiler leaks occur for a multitude of reasons, including broken seals, excessive pressure, or corroded components. You may be able to identify a leak in the central heating pipework, in which case a plumber is able to fix it. However, a leak inside the boiler requires troubleshooting by a Gas Safe heating engineer.
  • Hot water but no heat: A Vaillant boiler may produce domestic hot water but no central heat because of air trapped in the radiators, a broken diverter valve, or if you have a combi boiler and it is set to produce hot water but not heat. The latter presents an easy solution: you simply readjust the heating settings. Trapped air is an easy fix as well, as it only requires you to bleed out your radiators. However, it’s best to call in professional help if the two fixes above do not resolve the problem and you suspect that your Vaillant combi has a faulty diverter valve.
  • Low boiler pressure: The pressure becomes low when there is a leak in the heating system. You must find and rectify the leak and have a plumber or Gas Safe engineer fix it before attempting to repressurise the boiler.
  • Frozen condensate pipe: Condensate pipes often freeze when the outdoor temperatures plummet below 0°C. Some Vaillant boilers, like those in the ecoTEC range, come with anti-freezing technology to prevent the condensate from freezing and blocking the pipe. However, not every Vaillant boiler comes with this feature, so it continues to be a problem on the chillier winter days. It’s usually possible to thaw out a frozen condensate pipe by pouring warm water over it.
  • Kettling: Boilers produce a kettling noise when too much limescale clogs the internal components, like the heat exchanger. Get a Gas Safe heating engineer to examine the boiler and determine the extent of the blockage. A severely blocked heat exchanger may need a replacement. At this point, it might make financial sense to replace the boiler itself if it’s old, out of warranty, and has an irreparable heat exchanger.
  • Boiler lockout: A Vaillant boiler may lock itself out due to a system blockage, repeated ignition failure, excessive pressure, or any other issue that causes it to operate incorrectly or unsafely. Attempt to diagnose the underlying issue using the fault codes on the display screen and call a Gas Safe engineer for further assessment and repairs.
  • Pilot light not igniting: Debris may be blocking the pilot light jet, and there may be a disruption to the gas supply. A faulty pilot light requires troubleshooting by a Gas Safe engineer.
  • Vibrating, gurgling, or banging noises: These noises may indicate ignition issues, airlocks in the system, pump malfunctions, or debris buildup. A professional assessment by a Gas Safe engineer is vital in troubleshooting a noisy boiler.
Vaillant boiler problems
Common problems of Vaillant boilers

Note that older, out-of-warranty Vaillant boilers that experience frequent faults may cost more to maintain as time goes by and repair bills mount. At HeatingForce, we recommend considering a replacement boiler if your ageing Vaillant is past its warranty term and racking up repair costs over the £500 mark. You’re able to start comparing boilers using Heatable’s anonymous heating questionnaire and boiler selection tool right on your screen.

What are the best Vaillant boiler models?

Below are the four best Vaillant boiler models, selected based on performance, efficiency, and user-friendliness.

  • Vaillant ecoTEC Exclusive
  • Vaillant ecoTEC Plus
  • Vaillant ecoFIT Pure
  • Vaillant ecoTEC Pro

Our experts at HeatingForce explain the key advantages these four Vaillant boilers offer in the sections below.

Vaillant ecoTEC Exclusive

Vaillant ecoTEC Exclusive is a premium combination boiler that’s suitable for medium to large homes, with options of 35kW or 43kW outputs. The ecoTEC Exclusive offers the following four advantages listed below.

  • High flow rate: The ecoTEC Exclusive provides a flow rate of 14.5 (35kW) & 17.8 (43kW) litres per minute, which is considerably higher than what most combination boilers offer. This high flow rate allows households with high hot water demand to get plenty of hot water while running several taps or showers at once.
  • Smart controls: The Vaillant ecoTEC is fully compatible with vSMART™ heating control, which allows the boiler to adjust its output levels based on the outdoor temperature. This ability helps the boiler tailor its output and thus conserve fuel.
  • Eco-friendliness: The ecoTEC model is 85% recyclable, making it an eco-friendly choice for environmentally-conscious homeowners.
  • Quiet operation: Vaillant ecoTEC is Quiet Mark approved. This certification indicates a quieter operation compared to other boilers (although Quiet Mark does not release decibel levels), contributing to a more comfortable home environment.
  • Housebuilder Products Award (2018): Vaillant ecoTEC has been awarded at the Housebuilder Products Awards 2018 for its performance, control, and efficiency, showcasing its premium quality.

Vaillant ecoTEC Exclusive prices range between £1,900 and £2,400 excluding boiler installation costs.

Vaillant ecoTEC Plus

The ecoTEC Plus is a flexible combination boiler suitable for mid-sized and large homes, with models ranging in heating output from 25kW to 38kW. The three primary benefits of the Vaillant ecoTEC Plus boiler are listed below.

  • Wide modulation range: The boiler has a wide modulation range of up to 1:6, which allows the boiler to adjust its heating output in increments, to match the exact requirements of your home. This ability ensures that the boiler burns only the necessary amount of gas to provide the heating you need.
  • Near-instant hot water delivery: The boiler is capable of delivering hot water in just 5 seconds, so you don’t need to wait for the water to warm up as you turn on a tap or shower.
  • Smart control systems: You’re able to pair the boiler with Vaillant’s smart control systems, such as the sensoCOMFORT system control, or myVaillant app, for precise heating control and energy optimisation. These smart control systems allow for more precise control over your heating settings, which can help save both energy and heating costs.

The features listed above contribute to the precision heating capabilities of the Vaillant ecoTEC Plus boiler and ensure that it’s able to balance comfort and fuel efficiency.

Prices for the Vaillant ecoTEC Plus range between £1,600 and £2,000 (boiler-only).

Vaillant ecoFIT Pure

Vaillant ecoFIT Pure is an accessible combination boiler suitable for small to medium-sized homes, with options of 25kW, 30kW, or 35kW outputs. The ecoFIT Pure offers the following advantages listed below.

  • Cost-effectiveness: Vaillant ecoFIT Pure is priced between £850 to £1,100, so it’s a budget-friendly choice for homeowners without compromising on performance or quality.
  • Ease of use: Vaillant ecoFIT Pure comes with easy-to-use controls, a built-in filling loop, and a pressure gauge. These features facilitate straightforward operation and maintenance.
  • High energy efficiency: The ecoFIT Pure boasts a 94% energy efficiency rating, which means that the boiler converts 94p into heat for every pound you spend on gas.
  • Compact design: The ecoFIT Pure features a compact design that allows the boiler to fit into a kitchen cupboard. The small footprint helps homeowners conserve precious floor space in their homes.
  • Wide modulation range: Vaillant ecoFIT Pure has a wide modulation range that adjusts its output to meet the home’s heating demand with greater precision. The high modulation range eliminates needless energy consumption, thus helping reduce energy bills over time.

Vaillant ecoFIT Pure prices range between £850 and £1,100 without installation.

Vaillant ecoTEC Pro

Vaillant ecoTEC Pro is a combination boiler range suitable for small to medium-sized homes, available in outputs of 24kW, 28kW, or 30kW. The ecoTEC Pro range comes with the following three advantages outlined below.

  • Quick hot water delivery: The ecoTEC Pro is engineered to deliver hot water within just 5 seconds. Providing instant hot water whenever needed is a significant advantage that enhances user convenience.
  • Smart compatibility: Vaillant ecoTEC Pro is compatible with Vaillant’s vSMART™ smart technology app, which allows homeowners to enjoy a modern, tech-savvy heating system. This smart compatibility enables precise control over heating settings for improved energy savings and user convenience.
  • Extended warranty: Vaillant ecoTEC Pro offers a standard 5-year guarantee with the possibility of an extension to 7-10 years. These extended warranty terms provide homeowners with peace of mind regarding the long-term reliability and support of their heating system.

Vaillant ecoTEC Pro prices range between £1,100 and £1,700 without installation.

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What are the Vaillant boiler parts?

Below is a table summarising the most essential Vaillant boiler parts.

Vaillant boiler parts Function Model
Heat exchangers Transfers heat from the burner to the central heating water ecoTEC plus 824 – 0020018181
ecoTEC plus 831 – 0020018182
ecoTEC plus 837 – 0020025040
Burners Produces heat by combusting fuel (natural gas or LPG) ecoTEC plus 824 – 049324
ecoTEC plus 831 – 049345
ecoTEC plus 837 – 050430
Flues Expels toxic exhaust gases to the outdoors ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937,

ecoTEC PRO 24,

ecoTEC PRO 28 – 1376628

Ignition systems Ignites the fuel flowing into the burner ECOmax PRO 18 E,ECOmax PRO 28 E – 1373353
Pump Circulates hot water throughout the central heating system ecoTEC exclusive 832,

ecoTEC exclusive 838,

VUW 326/4-E,

VUW 386/4-E – 1383285

Control panel Console that allows users to control boiler functions ecoTEC plus 824 – 0020052093

ecoTEC plus 831 – 0020052093

ecoTEC plus 837 – 0020052093

Gas valve Controls the flow of gas to the boiler’s burner ecoTEC PLUS 824,

ecoTEC PLUS 824,

ecoTEC PRO 24 – 1383153

Expansion vessel Absorbs excess pressure as the water inside the boiler heats and expands ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937,

ecoTEC PRO 24,

ecoTEC PRO 28 – 1374029

Pressure relief valve (PRV) Allows the boiler to release pressure when it climbs above the normal operating levels ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937,

ecoTEC PRO 24,

ecoTEC PRO 28 – 1375069

Overheat thermostat Regulates the temperature of water that the boiler heats ECOmax PRO 18 E,

ECOmax PRO 28 E,

VU 186-O,

VU 286-O – 1373411

Diverter valve Allows a combi boiler to alternate its function between central heating and domestic hot water ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937,

ecoTEC PRO 24,

ecoTEC PRO 28 – 1383607

ecoTEC exclusive 832,

ecoTEC exclusive 838 – 1374425

ecoTEC PRO 24,

ecoTEC PRO 28 – 1382956

Air vents Allows the heating system to expel air trapped in the water ecoTEC exclusive 832,

ecoTEC exclusive 838,

ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937,

ecoTEC PRO 24,

ecoTEC PRO 28 – 1375348

Condensate trap / drain Collects and removes condensate produced by the boiler during operation ecoTEC PRO 24,

ecoTEC PRO 28 – 1376656

ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937 – 1376658

Heat exchangers for Domestic Hot Water (DHW) Transfers heat from the burner to the domestic water ecoTEC PRO 24,

ecoTEC PRO 28 – 1379874

ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837 – 1376534

Filling Loop Allows users to top up their central heating system if the water pressure is low ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937 – 0020010295

Filters Prevents sludge and unwanted debris from accumulating inside the boiler’s internal components ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937,

ecoTEC PRO 24,

ecoTEC PRO 28 – 1376556

ecoTEC exclusive 832,

ecoTEC exclusive 838 – 1372784

ecoTEC exclusive 832,

ecoTEC exclusive 838,

ecoTEC PLUS 824,

ecoTEC PLUS 831,

ecoTEC PLUS 837,

ecoTEC PLUS 937,

ecoTEC PRO 24,

ecoTEC PRO 28 – 1372783

1. Heat exchanger in Vaillant boilers

A heat exchanger in Vaillant gas boilers transfers heat from the burner’s flame to the water for central heating. The heat exchanger t is essential because it allows for the effective conversion of heat generated by the burner flame into warmth for the home.

Vaillant’s gas boiler heat exchangers are crafted from stainless steel or aluminium, depending on the model. These materials are renowned for their superior heat transfer capabilities and their ability to resist corrosion. Owing to these materials, the heat exchanger is capable of enduring the constant stresses produced by high heat, pressure, and moisture.

Vaillant design their heat exchangers for long-lasting performance, but issues may crop up nonetheless, including fractures from continual use and obstructions from limescale or heating sludge accumulation. The cost of replacing a heat exchanger in a Vaillant gas boiler typically lies between £200 and £400, not considering the labour fees.

2. Burner in Vaillant boilers

A burner in Vaillant gas boilers generates the flame required to heat the water circulating in the boiler. The heat exchanger then transfers the heat from this flame to the water flowing to a home’s radiators and (separately) taps and showers.

All Vaillant gas boilers’ burners are engineered to ensure efficient combustion, a process critical for the effective operation of the boiler. These burners are designed to mix air and gas in the right proportion, creating a clean and powerful flame that optimises energy use. However, all gas boiler burners are vulnerable to wear and tear and blockages due to dirt or debris affecting the air or gas flow, which can compromise the combustion process. The cost of a replacement burner for a Vaillant gas boiler ranges between £100 to £300, excluding the labour charges for the replacement process.

3. Flue in Vaillant boilers

A flue in Vaillant gas boilers serves the crucial function of safely venting out the combustion gases generated by the boiler to the exterior of the building. This process ensures that there is no risk of carbon monoxide accumulation within the living spaces.

All Vaillant boilers’ flues are designed to meet the stringent safety and environmental standards required in the UK. The flues are constructed with high-quality materials that can withstand the high temperatures and corrosive nature of the combustion gases being vented out. There are no known quality issues with Vaillant boilers’ flues. However, common issues potentially affecting all boiler flues include soot or debris accumulation, corrosion, and wear-and-tear due to constant exposure to hot gases. The cost of a replacement flue for a Vaillant gas boiler is £75 to £250 without labour.

4. Ignition system in Vaillant boilers

The ignition system in Vaillant boilers is a key component responsible for initiating the combustion process. This system comprises ignition electrodes that produce a spark to ignite the gas flowing into the burner.

Vaillant’s ignition electrodes are engineered to withstand the demands of frequent ignition cycles. However, as with all boiler components, wear-and-tear occurs in ignition electrodes with age. A cracked or damaged electrode may lead to inconsistencies in igniting the gas, causing the boiler to operate intermittently, or in severe cases, preventing the boiler from igniting altogether. Any malfunction in the ignition system necessitates immediate attention—either repair or, more preferably, replacement to restore the boiler’s functionality. The cost for a replacement ignition electrode in a Vaillant boiler ranges from £70 to £90, excluding labour.

5. Pump in Vaillant boilers

A pump in Vaillant boilers is an indispensable component that ensures a continuous flow of water through the home’s pipework and radiators. The pump thus enables the boiler to warm the living spaces. Vaillant combi and system boilers come equipped with internal pumps, while regular boilers operate with pumps installed externally at the heating pipework.

Vaillant boilers utilise high-quality circulator pumps that are engineered to resist wear and tear for many years, ensuring a reliable circulation of water within the heating system. However, these pumps may develop faults over time, such as gasket leaks. Gasket leaks present a relatively simple fix. However, severe pump issues, like broken bearings or motor failure, might necessitate a complete replacement of the faulty pump. The cost of a replacement pump in a Vaillant boiler ranges from approximately £200 to £250, excluding labour.

6. Printed Circuit Board (PCB) in Vaillant boilers

The Vaillant boiler relies on its Printed Circuit Board (PCB) to manage its operations. The PCB acts as the command centre and ensures every electrical component works in unison according to user settings.

Vaillant designs every PCB with precision, but no component is entirely free from potential issues. Over its lifespan, a PCB could encounter problems like disconnected wiring, which might result from the boiler’s natural vibrations or simple wear and tear. Another significant challenge is internal leaks. When water contacts the PCB, it can disrupt its functionality or even completely incapacitate it. In such instances, the best course of action is often replacement. Installing a new PCB in a Vaillant boiler is a task for professionals, and the component itself typically costs between £200 to £350, not including the technician’s service fee.

7. Gas valve in Vaillant boilers

The gas valve is an essential component in Vaillant boilers. The valve regulates the flow of gas into the combustion chamber, ensuring the right amount is available for efficient heating.

Vaillant prioritises safety and durability in every gas valve they incorporate, and there are no issues for which Vaillant gas valves are known. However, over time, a gas valve might lose its ability to regulate the gas flow as effectively, generally due to wear or debris buildup. In some cases, a malfunctioning valve may either restrict the gas flow or flood the combustion chamber with gas, both of which are hazardous occurrences that impede the boiler’s functionality. Such issues require prompt repairs or replacement for safety and efficiency reasons. Procuring a new gas valve for a Vaillant boiler typically costs £150 to £200, excluding labour costs.

8. Expansion vessel in Vaillant boilers

The expansion vessel in Vaillant boilers is a crucial component designed to accommodate the expansion of water as it heats up. An expansion vessel thus maintains a safe and steady pressure level within the heating system. The boiler heats water when the thermostat signals a need for heating, and the hot water expands into the vessel, preventing an undue rise in system pressure. The precise operation of the expansion vessel is essential for the smooth functioning of the boiler, whether it’s providing central heating or domestic hot water in combi boilers.

Vaillant’s expansion vessels are built for durability, ensuring they retain their structural integrity under the constant pressure changes within the heating system. However, expansion vessels may face issues such as the deterioration of the diaphragm. Such an issue may necessitate the replacement of the expansion vessel, depending on the severity. Typically, the cost of replacing an expansion vessel in a Vaillant boiler ranges from £100 to £200, excluding labour.

9. Pressure Relief Valve (PRV) in Vaillant boilers

The pressure relief valve (PRV) in Vaillant boilers is a fundamental safety component that ensures the pressure within the heating system remains within the normal operating range. The pressure relief valve activates to release the excess pressure, thereby averting any potential damage or hazards when the system pressure escalates beyond a specified limit (usually above 3 bar). This mechanism is vital for central heating provisions in all boiler types.

Vaillant’s pressure relief valves don’t have any documented flaws. However, an ageing PRV may become prone to leaking or failing to reseal properly after activation, thus leading to continuous water discharge or not releasing pressure when needed. A leaky valve may often be a result of debris or mineral build-up, while a non-sealing valve might indicate a worn or damaged seal. The typical cost for replacing a pressure relief valve in a Vaillant boiler ranges from £30 to £60, excluding labour costs.

10. Overheat thermostat in Vaillant boilers

The overheat thermostat in Vaillant boilers monitors the temperature of the water within the system and ensures that it remains within a safe operating range. The overheat thermostat intervenes by shutting down the boiler to prevent any potential damage or hazardous situations should the water temperature rise beyond a specified threshold.

Vaillant’s overheat thermostats are designed to provide precise temperature monitoring and have no documented quality problems. Nonetheless, these thermostats may encounter issues, such as a failure to reset or inaccuracies in temperature sensing. A malfunctioning overheat thermostat could either shut down the boiler unnecessarily or fail to act during an actual overheating event, both of which could disrupt the boiler’s operation. Resolving issues with the overheat thermostat typically entails either resetting or replacing the component. While a reset might restore functionality in some cases, persistent or recurrent issues often warrant a replacement. The cost of replacing an overheat thermostat in a Vaillant boiler ranges from £40 to £80, excluding labour charges.

11. Diverter valve in Vaillant boilers

The diverter valve in Vaillant combi boilers is a key mechanism that directs the flow of heated water either towards the central heating system or to the domestic hot water outlets, based on the user’s demand. When the heating is turned on, the diverter valve channels water to the radiators, and when a hot water tap is opened, it reroutes water to the hot water outlets.

Vaillant’s diverter valves are designed to ensure a seamless switch between heating and hot water modes. However, over time, they may face issues such as a failure to switch, leakage, or sticking in one position, which could affect the boiler’s ability to switch between heating and hot water modes. Some minor issues might be fixed by a clean or a reset, but more severe problems typically require a replacement of the diverter valve. The typical cost for replacing a diverter valve in a Vaillant boiler ranges from £100 to £250, excluding labour costs.

12. Air vents in Vaillant boilers

The air vent in Vaillant boilers serves as a critical component for managing air within the heating system. Its primary function is to expel any air trapped in the system, ensuring a consistent flow of water through the central heating system. The efficacy of the air vent is instrumental in maintaining the boiler’s efficiency and performance.

There have been no issues documented specifically with Vaillant’s air vents. That said, any boiler’s air vent might encounter issues, such as blockages or leaks. A blocked air vent may be unable to let air out of the system properly, thus affecting the flow of water. Meanwhile, a leaky air vent often results in water and pressure loss. Cleaning, repairing, or replacing the air vent may be necessary depending on the severity of the flaw. Cleaning might resolve minor blockages, while a replacement is often necessary for persistent blockages or leaks. The typical cost for replacing an air vent in a Vaillant boiler ranges from £10 to £20, excluding labour costs.

14. Condensate trap/drain in Vaillant boilers

The condensate trap in Vaillant gas boilers is an integral component designed to collect and safely dispose of the acidic water, or condensate, produced during the combustion process. Its presence is vital as it prevents the condensate from causing potential damage to the boiler and the surrounding environment.

Vaillant’s condensate drains are engineered to withstand the acidic nature of the condensate. This robustness ensures that the trap remains effective and durable over its lifespan, safeguarding the boiler and its components from potential harm. That said, the component may experience blockages from debris and potential wear from the continuous flow of acidic water. Such issues may require a complete replacement of the trap if they are severe enough. A Vaillant gas boiler’s condensate trap replacement typically costs between £30 and £100, not including the labour costs associated with its fitting.

15. Heat exchanger for Domestic Hot Water (DHW) in Vaillant boilers

The domestic hot water (DHW) heat exchanger (also referred to as the “secondary” heat exchanger) in Vaillant combination boilers transfers heat to the mains water. This heat exchanger is instrumental in delivering hot water to homes without the need for a storage tank. Vaillant system and regular boilers do not have this secondary heat exchanger, since they heat the domestic hot water inside a cylinder indirectly via a coil.

Vaillant’s DHW heat exchangers are manufactured using premium materials that facilitate their heat transfer capabilities and resistance to the rigours of daily use. There are no known issues regarding the quality of Vaillant boilers’ secondary heat exchangers. That said, years of wear and tear associated with frequent heating-cooling cycles, as well as mineral deposits, may cause this component to operate inefficiently or develop faults. The cost to replace a DHW heat exchanger in a Vaillant combination boiler usually falls between £150 and £300, without factoring in the labour expenses for its installation.

16. Filling loop in Vaillant boilers

The filling loop in Vaillant boilers allows the boiler user to replenish the central heating system with water. The filling loop essentially connects the heating system to the mains, giving the user a chance to top up the pressure to normal levels in the event of pressure loss. Some Vaillant boilers have an integral filling loop whilst others need to be refilled via an external hose.

There are no issues reported specifically about Vaillant’s filling loops. However, these components may degrade after many years of use. The replacement cost of a Vaillant filling loop typically ranges between £40 and £80, excluding the installation labour charges.

17. Filter in Vaillant boilers

The filter in Vaillant boilers is an essential component designed to trap and remove any impurities or debris present in the central heating system’s water. Purifying the water ensures smooth and efficient boiler operation, reducing the risk of blockages and potential damage to other critical components.

Heating engineers generally clean boiler filters during annual boiler service. However, an older filter that’s failing to trap debris properly may require a replacement. The replacement cost of a Vaillant boiler filter is typically between £120 and £200, not including the labour fees for its installation.

How is the customer service of Vaillant boilers manufacturer?

The customer service of Vaillant boilers is of a high standard, with the vast majority of Vaillant boiler owners happy with the service they get. The satisfaction is evident in the positive reviews Vaillant have amassed on TrustPilot UK. Vaillant gets 4.5 out of 5 stars on Trustpilot, based on about 20,000 reviews. The overwhelming majority of reviewers commend Vaillant specifically for the quality of customer assistance.

Vaillant UK offer their customers several means of contacting the company’s support team. The list below outlines the contact information for customers seeking Vaillant support on a range of matters.

  • General contact: The general support line is available by phone at 0333 202 7059 and by email at [email protected].
  • Annual boiler service: You’re able to inquire about annual Vaillant boiler service by ringing the line at 0330 100 3150 (open 7 days a week, 364 days a year).
  • Boiler repair: You’re able to inquire about boiler repairs by calling 0330 100 3150.
  • Homeowner technical lines: Homeowners are able to reach Vaillant’s technical support at 0344 736 0049. The phone is available Monday to Friday, 8am – 6pm, Saturday between 9am and 12pm, and is closed on Sundays.

Does customer service help for Vaillant boiler installation?

Yes, the Vaillant customer service team does help with boiler installation. Gas Safe engineers who install Vaillant boilers are able to get assistance if questions arise during installation. A study performed by Which? found that the majority of engineer respondents were happy with Vaillant’s installer support, despite inconsistencies from time to time.

Recently, Vaillant unveiled the Interactive Service Assistant (ISA). ISA is an app that allows Vaillant to better help installers service, repair, and install heating devices. The ISA gives users clear step-by-step navigational instructions heating engineers installing or servicing Vaillant boilers.

Are Vaillant boilers’ parts available for replacement?

Yes, Vaillant boilers’ p​arts are available for replacement. Heating engineers are able to easily source Vaillant boiler parts at online boiler part suppliers or brick-and-mortar heating merchants. The Which? study cited above revealed that engineers who install Vaillant boilers are particularly happy about the availability of spare Vaillant parts. Having the spares readily available means that engineers are able to troubleshoot faults quickly, without leaving you waiting for days without heat and hot water while a part ships from another part of the country.

Is it costly to repair Vaillant boilers for a possible problem?

Whether it’s costly to repair Vaillant boilers for a possible problem depends on what the problem is, the age of your boiler, and who you hire to do the repairs. The cost of hiring a technician for repairs is about £85-120+ VAT, so that’s the minimum you should expect to pay for fixing a Vaillant boiler. The rest of the price depends on the component that’s causing the fault and how long it takes to repair or replace it. For example, the faulty air vent behind a leak in your system may cost £100 to replace, including labour. Meanwhile, a cracked heat exchanger may set you back as much as £600, including the replacement part and labour.

The best way to keep your Vaillant boiler running error-free, postpone age-related faults, and keep repair costs low is to get boiler service for the boiler. The annual service costs roughly £100 per year and gives the servicing engineer a chance to pinpoint faults early before they deteriorate. Annual boiler service is additionally a condition for the validity of the manufacturer’s warranty.

Note that a Vaillant boiler that’s very old, out of warranty, and breaking down often is most likely on its way out. Frequent service calls and climbing repair bills mean that the boiler’s components have outlived their lifecycle, and you’re better off considering a replacement boiler. At HeatingForce, we recommend looking around for a replacement boiler once your repair bills go past £500 and the boiler is no longer under warranty. Heatable’s online boiler selection tool is an excellent place to begin your search, as you’re able to use the tool to get fixed-price, no-obligation quotes on a range of new boilers on your screen in just 90 seconds.

What are the Vaillant boiler error codes?

There are upwards of thirty Vaillant boiler error codes, and each one bears a specific cause and solution. Below is a list of the four most common Vaillant boiler fault codes.

  • F22 fault code: The fault code F22 is common on Vaillant ecoTEC boilers, and it represents low water pressure in the heating system. Low system pressure may stem from a faulty pressure sensor or a leak in the system.
  • F29 fault code: Fault code F29 occurs on ecoTEC boilers when there is a flame failure. The flame may fail to stay lit as a result of carbon buildup and the subsequent blockages, or because there is an issue with the gas supply.
  • F75 fault code: Vaillant ecoTEC, ecoTEC Plus, and ecoPRO boilers display the F75 fault when there is a pressure issue in the system. Either a faulty circulator pump or malfunctioning pressure sensor may be the root cause of this pressure issue and the F75 fault code.
  • F28 fault code: The F28 fault code is common on Vaillant ecoTEC Pro, ecoTEC Pro Plus, and Turbomax Plus 824/828E boilers. F28 means that the boiler has failed to ignite after three attempts. The error may stem from a malfunctioning gas valve, an issue with the gas supply, or a faulty electrode.

Note that all of the four fault codes above require professional diagnostics and troubleshooting by a Gas Safe-registered engineer.

How aesthetic is the design of the Vaillant boilers?

The design of the Vaillant boilers is both modern and minimalistic. The boilers’ casing features a neutral white colour palette with an overall sleek aesthetic, thus allowing the boiler to blend it seamlessly into most interior settings. The casing is sleek and clean despite its minimalistic vibe, and this elegance makes Vaillant boilers an appealing addition to a home’s interiors. However, you may not need to install your Vaillant boiler in a conspicuous location, as many of the models are compact enough to fit snugly and out-of-sight into standard kitchen cupboards and other types of cabinetry. Below is a table summarising the physical dimensions of the Vaillant boiler ranges.

Vaillant boiler model Height (mm) Width (mm) Depth (mm)
Vaillant ecoFIT Pure Combi 25 600 375 280
Vaillant ecoFIT Pure Combi 30 600 375 280
Vaillant ecoFIT Pure Combi 35 600 375 280
Vaillant ecoTEC Pro Combi 24 720 440 338
Vaillant ecoTEC Pro Combi 28 720 440 338
Vaillant ecoTEC Pro Combi 30 720 440 338
Vaillant ecoTEC Plus Combi 825 720 440 338
Vaillant ecoTEC Plus Combi 832 720 440 338
Vaillant ecoTEC Plus Combi 835 720 440 372
Vaillant ecoTEC Plus Combi 838 720 440 406
Vaillant ecoTEC Exclusive with Green iQ Combi 627 720 440 338
Vaillant ecoTEC Exclusive with Green iQ Combi 835 720 440 406
Vaillant ecoTEC Exclusive with Green iQ Combi 843 720 440 474
Vaillant ecoTEC Plus System 48kW 720 440 405
Vaillant ecoTEC Plus System 64kW 720 440 473
Vaillant ecoFIT Pure System 625 700 390 280
Vaillant ecoFIT Pure System 630 700 390 280
Vaillant ecoTEC Exclusive with Green iQ System 720 440 338
Vaillant ecoTEC 46kW System 800 480 450
Vaillant ecoTEC 65kW System 800 480 472
Vaillant ecoFIT Pure 412 Regular 600 375 280
Vaillant ecoFIT Pure 415 Regular 600 375 280
Vaillant ecoFIT Pure 418 Regular 600 375 280
Vaillant ecoFIT Pure 425 Regular 600 375 280
Vaillant ecoFIT Pure 430 Regular 600 375 280
Vaillant ecoFIT Pure 435 Regular 600 375 280
Vaillant ecoTEC Plus Regular 720 440 348

Does a Vaillant boiler fit into intended space?

Whether a Vaillant boiler fits into the intended space depends on the three factors listed below.

  • Intended location: Some locations make for a tighter fit than others. For example, a kitchen cupboard is generally able to accommodate a boiler that’s 700mm X 400mm X 300mm (H x W x D) or smaller. Don’t simply measure the cupboard and see if the model fits those exact dimensions because the boiler needs to have adequate clearance on either side, which differs between models. The desired boiler models’ installation instructions should provide these clearances, thus allowing you to figure out where to fit the appliance.
  • Boiler model: Some Vaillant boilers are smaller than others. For example, the ecoFIT Pure combi range measures just 600mm X 375mm X 280mm (H x W x D), so it fits into standard kitchen cabinets without issues. On the other hand, the ecoTEC system 46kW model measures 800mm X 480mm X 450mm, which makes it far too large to fit into a cabinet. Instead, this model is more suitable for utility rooms or airing cupboards.
  • Boiler type: Vaillant combi boilers are easier to fit in smaller homes since they do not require any additional water storage facilities. In contrast, system and regular boilers from Vaillant need hot and cold water storage tanks to operate, and the latter take up additional floor space.

Do Vaillant boilers have an electronic control panel?

Y​es, Vaillant boilers have electronic control panels. The Vaillant boiler control panel boasts a sleek and modern design. The digital display provides clear temperature readings and operational statuses. Users are able to access a series of intuitive buttons and dials, facilitating easy adjustments and settings configurations directly beneath the display. The panel additionally includes connection ports for external devices, ensuring flexibility in system setups.

What are the alternatives to Vaillant boilers?

The two best alternatives to Vaillant boilers are listed below.

  • Viessmann: Viessmann boilers are considered to be premium on the UK market, much like Vaillant boilers. However, there are two areas where Viessmann boilers outperform their Vaillant counterparts. Firstly, Viessmann boilers offer some of the highest energy efficiency levels, which are typically 3-4% above those offered by Vaillant. Secondly, Viessmann boilers cost less than Vaillant equivalents. The price difference may add up to several hundred pounds, depending on the model.
  • Worcester Bosch: Worcester Bosch is a household name in the UK, and are among the nation’s top-tier boiler brands like Vaillant. Worcester boilers come in a range of types and sizes, just like their Vaillant equivalents. Worcester Bosch boilers are a bit more energy efficient than Vaillants and have slightly longer standard warranty terms. The prices of Worcester boilers are lower on average than those of Vaillant’s boiler ranges.

You’re able to compare the prices and features of Viessmann, Worcester Bosch, and Vaillant using Heatable’s online boiler selection tool.

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How to compare Vaillant Boilers to other boiler brands?

Consumers should compare Vaillant boilers with other brands using the following four measurements listed below.

  • Build quality: Potential Vaillant buyers should compare Vaillant’s build quality to that of competing brands. Vaillant boilers are known for their superb build quality among users and heating engineers. A study conducted by Which? revealed that 88% of Vaillant boiler users were satisfied with their boiler, which is higher than the national average. 44% of respondents claimed to be extremely satisfied with their Vaillants, which is a significant satisfaction score considering Britons’ general animosity and mistrust of their boilers. Heating engineers that responded to the Which? survey gave Vaillant boilers 5 stars out of 5 in the build quality category.
  • Energy efficiency: People considering getting a new Vaillant boiler should compare Vaillant’s energy efficiency ratings to those of other boiler brands. Most Vaillant boilers have efficiency ratings of at least 87%, which places them in the average-to-high category. However, other boiler brands have efficiency ratings of up to 97%. This means that only 3% of the energy the boiler system produces is lost during the production process. High energy efficiency means a smaller ecological footprint and lower utility bills.
  • Reputation: Consumers should compare Vaillant boilers to other brands by their customer service and reputation. Vaillant boast high ratings on Trustpilot for their customer service. Vaillant have additionally been operating for about 150 years, which indicates a high degree of trustworthiness.
  • Warranties: Consumers should compare Vaillant boilers with their warranties. When upgraded, Vaillant offer excellent warranties that last between 10 and 15 years. However, the company’s standard warranty terms are average, at only 5-7 years.

Heatable offer a simple way to compare Vaillant against other boiler brands. All you need to do is enter a few details about your property and heating system configuration to get Heatable’s list of suitable boilers along with fixed-price quotes.

What do HeatingForce experts suggest about Vaillant boilers?

HeatingForce experts suggest that Vaillant boilers are suitable for customers who don’t mind spending more upfront to get a boiler with an incredibly reliable build. Vaillant boilers are some of the most expensive on the UK market, with prices ranging between £800 and £2,800, excluding installation. The high price tag buys some of the highest quality boiler manufacturing, a fact to which UK’s heating engineers attest. Vaillant have received the highest possible grades from the nation’s engineers specifically for their build quality. Vaillant’s superior construction means that you should expect your boiler to last a long time without developing serious faults.

However, our view at HeatingForce is that you’re able to get boilers of a similar (if not superior) quality, with greater energy efficiency and a lower price point from Viessmann. Viessmann boilers are designed to resist wear and tear with their quality internal components, and some models come with standard warranties that are over 10 years. Viessmann boilers are additionally more energy-efficient (on average) than their Vaillant counterparts. The 3-5% increase in energy efficiency translates into 3-5% savings on utility bills for the boiler users. Viessmann boilers offer all of the advantages above while costing approximately 20% less than Vaillant equivalents, on average.

What to know before purchasing a brand-new Vaillant boiler?

You should know the following three things before purchasing a brand-new Vaillant boiler.

  • Extended warranties are worth it: Vaillant’s standard warranties are on the short end of the scale, averaging about 5 years. You’re able to get an extended warranty for a fee, and the couple hundred quid is a worthy investment that buys you peace of mind for over a decade. Note that you’re able to get a Vaillant with a 10-year warranty as standard if you purchase the boiler through Heatable, without paying additional fees.
  • You’re about to get a premium boiler: Vaillant boilers are the cream of the crop in the UK. These boilers have extremely high customer and engineer satisfaction rates, and they’re known to last a long time without developing severe faults.
  • You’re able to find cheaper boilers with similar quality: Viessmann and Worcester Bosch boilers cost less than Vaillants on average, while offering high energy-efficiency levels, proven durability, customer satisfaction scores, and long standard warranties. Head to Heatable to get a no-obligation, detailed comparison between the prices and features of Vaillant boilers and their top UK competitors.
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