No Hot Water from your Boiler? Check This Before Calling An Engineer

In this 5-minute guide to boiler’s with no hot water, we’ve split it down into sections, so you can flick straight to the section that sounds like your problem.

No hot water from the boiler

We’ve also included a quick “fix” section with each, where possible.

  • No Heating Or Hot Water
  • I Have No Hot Water, But My Heating Works
  • Cold Water Works, But No Hot Water
  • No Hot Water In My Shower Only

Get the Best Gas Safe Engineer to Fix a Lack of Hot Water

Before we carry on, any repairs or replacements will require a skilled Gas Safe engineer to look at the problem; you can book one in here.

With a trusted engineer in your pocket, you might consider upgrading your old, outdated boiler with a high quality Worcester Bosch from Heatable. They’re available as low as £1,785, with flexible financing and 10-year warranties. Found a better price elsewhere? Heatable will match and better it.

Worcester Bosch boilers - Trustpilot review

And, if you’re looking for a faults not listed here, checkout our guide to boiler problems.


No Hot Water Or Heating

Of all the diagnoses, this is the hardest one to pin-point without inspecting the boiler. The possibilities are pretty much endless but only a few require professional services from a registered boiler repair business.

#1 – No Power To Boiler

Is your boiler control panel blank? Are the power lights off?

Take a look at the control panel on your boiler. If you are getting adequate power, the panel should be functioning properly and displaying control options.

The Fix: Check our guide for boiler power issues.

Power issues are actually quite common and can be easily assessed and fixed. We’ve created a guide specifically for users with no power to their boiler here.

#2 – Faulty Heating Pump

On each boiler, there is a “flow” (hot water out) and a “return” (water returning to the boiler, after going around the heating) pipe.

Your flow pipe should be hot. The return pipe should be a little bit cooler; radiators and pipework will take some of the heat out of the water as it travels round the system.

If neither the flow or return are hot/warm, there’s a chance the pump isn’t circulating.

The Fix: Check our guide for heating pump problems.

Need to diagnose a faulty pump? We’ve created a guide to central heating pump problems here. Within the guide you can find more details about the causes of pump problems and some suggestions for how to fix them.

What kind of fuel does your boiler use?

Grab your fixed price online by 3PM, and get next-day boiler installation.

Worcester boilers installed from as little as £1,795.

#3 – The Pilot Light Has Gone Out

The pilot light is the small flame you see in your boiler. If this has gone out, it’s likely a fault code has appeared (check your owner’s manual to see what the fault code means).

The Fix: Contact a gas safe engineer.

We can’t advise fixes on gas related issues. Do not attempt to fix or correct pilot light problems on your own. You should contact a Gas Safe engineer.

You can speak to one here.

#4 – Hot Water But Faulty PCB/Display Panel

If you have power, and can hear internal parts working/moving, there’s a good chance you’ve got a faulty PCB and display panel.

Like other components in the boiler, they do break over time. This process can be sped up if your boiler is leaking water that’s made its way into the control panel.

The Fix: Check and replace your boiler’s panel.

Due to the complexity of the boiler’s display panel, the best option is to replace it. To gauge the boiler pressure, you have to be able to check the relevant data provided by the boiler’s panel.

The PCB is incredibly expensive. Expect a bill of around £500. If your boiler is over 5 years old or out of warranty, depending on the condition of other parts, it might be worth considering a replacement. A new boiler might cost less in the long run.

Typical installation prices start from around £1,800+. However, we’d recommend checking out Heatable (a boiler comparison site). They’re one of the cheapest for Worcester boiler installations and you can get your £1,785 price online, in less than 2 minutes here.

#5 – Faulty Programmer or Timer

No hot water or heating could mean that you have a faulty timer or programmer.

The Fix: Reset the system.

Check the owner’s manual for details on how to reset the programmer and timer.

And, if you’ve had a power cut, this temporary loss of electrical power supply can mess with the time/date stamp on both devices. If you’ve programmed your heating and hot water, it could be set to the wrong time. Check time/date stamps and change if necessary.

#6 – Frozen Condensate Pipe

If you’re getting no hot water or heating on cold mornings, or during winter, there’s a good chance the condensate pipe is frozen.

The condensate pipe vents flue gases from your property, and these are prone to freezing.

The Fix: Clear Blockage

Check the pipe for blockages/frozen debris. Clear the blockage and slowly thaw out the pipe.

#7 – Boiler Lockouts

A boiler lockout is a shut-down procedure. It’s a shut-down sequence initiated by the boiler when it realises there’s something not quite right.

The Fix: Check Error Code

There’s a tonne of reasons a boiler can lockout; some have been mentioned above.

The display panel will show a fault code. With that information in hand, head over to our page on common boiler lockout causes and fixes here.

#8 – Low Or No Pressure In The Boiler

Your boiler needs pressure in order to heat up hot water. If you have no hot water or central heating, it could be due to a loss of pressure.

The Fix: Get Help From An Expert

We’ve created a guide to why boilers lose pressure, and the fixes here.


No Hot Water But Heating Works

Not hot water but heating works

When there’s no hot water but the heating works, this is usually a sign of a faulty diverter valve.

However, it’s important not to jump to conclusions. We’ve had people contact us in the past with the same no water water/heating works problem. Their engineer fitted an expensive diverter valve, and it didn’t fix the problem.

The Fix: Contact An Expert

Here’s a guide to diagnosing a faulty diverter valve.

Remember, don’t jump to conclusions. There are other reasons you could be getting heating but no hot water, such as faulty S-plan, Y-plan or zone valves.

My advice would be to contact an engineer for a quote before spending any cash on repairs. If you’d prefer a replacement, you can get a price online here.


No Hot Water But Cold Water Works

Boiler working but no hot water

When you get no hot water, but the cold water works, there’s a few potential problems.

First, as this is quite a broad issue (it’s easier to diagnose when seeing the heating system), check out the first two sections first:

  • No Hot Water Or Heating
  • No Hot Water But Heating Works

Those cover actual boiler faults. But, we’ve been to properties where it’s not the boiler’s fault at all.

Have you smelt gas and turned off the gas valve?

If this is the case, you’ll get cold water from the hot tap, but as there’s no fuel for the boiler to burn (and heat the water), you won’t get hot water.

Did you try to increase the pressure of the boiler via the filling loop and close off more than one valve?

In this scenario, the gas lever is probably still open and ready to fuel the boiler, but the water supply for the hot, has been turned off.

The Fix: Check Water & Gas Levers

For the boiler to heat water it needs two things:

  • Water Supply
  • Gas Supply

You’ll want to be sure that both of these levers are open.

If your property has no water coming from the taps at all (perhaps you just moved in), there’s a good chance the mains stopcock (sometimes there’s more than one) has been turned off.

Make sure to turn this back on to get a supply of water to the boiler, taps and shower.


No Hot Water In Shower Only

If you’re getting no hot water in the shower only, but everywhere else is fine there’s a few explanations:

  • The mixing valve in the shower is stuck, or broken
  • Anti-scalding device set in the wrong position

The Fix: Replace Mixing Valve

If the mixing valve is stuck or broken, it needs to be replaced or fixed. Personally, for the sake of what they cost, I’d get it replaced.

On most newer showers you’ll have an anti-scalding device built in. If this is set too high, the water won’t heat up. It’s located behind the knob used to turn the heat of the shower up and down. Adjusting this can sometimes fix the problem.

That said, it’s unlikely this has suddenly just changed (so, unless you’ve just moved in, we’d head for the mixing valve).


What’s Next?

Still need someone to come and fix your hot water?  You can book one to take a look here.

Prefer a replacement boiler? We’d recommend getting a quote price from Heatable’s boiler calculator.

Whether you’ve got no hot water and heating, or just no hot water in your shower, we hope this has helped.

If you’re still stuck, drop a comment below and we’ll get back to you as soon as possible.

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