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5 Common Faults With Biasi Boilers [Problems, Fixes, and What to Do Next]

Welcome to our 5-minute guide to the most common faults with Biasi boilers, problems they point to, and possible fixes. Here, we’ll also explain how to reset a Biasi boiler, and how to find out your Biasi boiler’s age. Read on to learn more!

Before we go any further: only Gas Safe engineers should inspect and fix gas boilers.

To get the price for repairs, we’d suggest speaking to a local engineer. And, if you’d prefer to replace your unreliable boiler with a brand new one with a long warranty?

We suggest heading to Heatable. They’re an online boiler installation company focusing on technology rather than salespeople to keep costs down, so they fit Worcester boilers dirt cheap. You can get a fixed price on-screen in less than 90-seconds using this anonymous form.

Short On Time? Here’s a Summary of Biasi Fault Codes

If you’d rather jump right to the problem you’re experiencing instead of reading the entire guide, go ahead and use the one of the links below:

  1. Biasi boiler won’t ignite — Biasi fault codes ER01 and ER05
  2. No hot water to Biasi boiler
  3. Biasi air pressure switch fault (or fan fault) — green and red lights flashing
  4. Circulation issues with Biasi boiler — flashing with fault code ER04
  5. Biasi boiler makes a banging noise and locks out — fault code ER01

5 Common Biasi Boiler Problems

Below, we’ve listed the most common issues you’re likely to experience with a Biasi boiler. Luckily, with Biasi boilers, problems are typically easy to diagnose. That said, be sure to consult with a Gas Safe heating engineer if any of the boiler’s internal components need to be assessed.

Boiler Won’t Ignite — Biasi Fault Codes ER01 / ER05  

Possible Fault Codes: ER01 / ER 05

Biasi boilers problemsTroubleshooting a boiler that won’t fire up isn’t particularly easy. That’s because there are several issues that could be causing this problem.

From a safety point of view, your boiler won’t ignite if:

  • The fan isn’t operational, which means that flue gases can’t escape from your property
  • There is a burner problem, such as a blocked jet, or debris build-up
  • The gas supply is intermittent (sign of incorrect gas valve adjustment, or a faulty gas valve)

The Fix

The fix maybe simple, but the fault finding process can be complicated. So, it’s wise to call in a professional boiler engineer.

The fault code displayed on your display panel will help determine what’s wrong with your Biasi boiler. For example, a ER 01 error code will signal a burner fault, whereas the ER 05 will signal a fan fault.

Each component of the boiler will be need to be tested. For instance, the fan could be jammed. When the fan isn’t working, the air pressure senses it’s unsafe to fire up, and the boiler will lock out.

If the repair cost is below £500 and you still have warranty left on your boiler, we’d suggest going with repairs. Otherwise, we’d look at getting prices for a new boiler.

Biasi Boiler No Hot Water

The first thing to check when your Biasi boiler has no hot water, or no heating, is the diverter valve. A faulty diverter valve can cause issues, such as:

  • No hot water, even when the heating works
  • No heating, even when the hot water works
  • Radiators heat up slightly when running taps or showers

The diverter valve changes between the heating and hot water positions to direct water either to radiators and towel rails or taps and showers.

Over time, these valves can become stiff and get stuck. So, they could be stuck on the heating side, the hot water side, or somewhere in between, which would explain why you get hot water but no heating, or vice versa.

For examples, radiators that are half-heating up when hot water comes on could signal that the diverter valve is slightly open on the heating side even when the heating isn’t on.

The Fix

If your diverter valve is in good condition, a heating engineer may be able to free it so that it’s no longer stuck.

But, the time taken (and money spent on labour), means its sometimes worth considering a replacement (get a quick on-screen price here). After all, if the part is old and worn, there’s a good chance that this issue will show its ugly face again!

Biasi Fan / Biasi Air Pressure Switch Fault — Red and Green Lights Are Flashing  

Biasi boilers problemsDifferent Biasi boilers will display signs of faults in different ways. So, always check your owner’s manual to check what the particular sequence of flashing lights mean.

Typically, when the red and green lights are flashing on a Biasi boiler, it’s a sign of a problem with:

  • Fan operation, or a faulty fan
  • Wrong air pressure switch signals, or a faulty air pressure switch

The fan takes dangerous flue gases from your property. The air pressure switch (which is really a sensor) ensures that the fan is doing its job.

When the switch senses the fan isn’t doing its job, it locks out the boiler, and red and green lights start flashing.

The Fix

The first point of call is to check that the fan is operational, as fans can sometimes seize. Such a seizure is enough for the air pressure switch to notice the boiler isn’t operating safely and lock it out.

But what if the fan is working?

Then, a Gas Safe engineer can test the air pressure switch and the fan using a multi-meter. If the fan is working correctly and there’s no blockage in the flue, there’s probably a signal problem.

This could be a communication issue between the sensor and fan, fan and PCB or PCB and sensor. If all parts seem to be in working order, wiring is the likely issue.

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Boiler Circulation Issues — Biasi Error 04 

When a boiler develops an issue, it will show a corresponding fault code on the display board. Most of the time it will lock out, need to be fixed, then reset.

The Biasi error 04 relates to water. The problem is either:

  • A lack of water in the central heating system
  • Limited or no circulation of water

The Fix

First, check the boiler pressure. The reading on the pressure gauge should be around 1.5 bar. If it’s not, there’s a chance the boiler has lost water pressure, or not been topped up correctly. You will need to fill it via the external filling loop.

If the pressure seems fine, it’s likely a circulation fault. Circulation problems on Biasi boilers are almost always due to a pump fault; we’ve created a guide on pump faults and what to do next here.

Biasi Boiler Makes a Banging Noise, Then Stops Working — Fault Code ER01

Older Biasi boilers can start producing strange noises, which often sound like banging.

If your Biasi boiler is making banging noises when it fires up, and showing a ER 01 fault code, there’s a good chance there’s a problem with the burner. The jets could be blocked, or suffering from carbon build-up.

That said, the problem could be ignition-related too.

Ignition-related parts that cause issues are the electrode, ignition lead, and spark generator.

The Fix

After taking off the boiler’s casing, a Gas Safe engineer will be able to determine the problem quickly.

A burner that is clogged full of carbon is easy to spot. If this is the case, the build up is easy enough to clean.

Once cleaned, the boiler can be reset and this should clear the fault code on your Biasi boiler.

How to Reset a Biasi Boiler

If your Biasi boiler has locked out, it means that it detected a problem that may endanger the property, its occupants, or the boiler’s components. Once you’ve successfully resolved the underlying issue, you’ll need to reset the boiler to clear any fault codes and re-initiate its operation. Knowing how to reset a Biasi boiler is part of the core knowledge any boiler owner or operator should have.

Luckily, its usually as simple as pressing and holding the reset button for several seconds, then waiting several minutes for the boiler to fire up again. However, if your Biasi boiler model does not have a reset button, or the instructions above don’t work, you can find model-specific instructions in this Biasi boiler user manual compilation here.

How Old is My Biasi Boiler?

Wondering how old your Biasi boiler is and whether a recent boiler breakdown is cause for a replacement? Whilst it may not be immediately clear how old your boiler is, don’t fret — the year of production is typically included in the serial number.

To find out your Biasi boiler’s age, find the serial number — it should be on the interior of the front casing, or, failing that, on the drop-down panel. The last 4 digits of this number indicate the month and year the boiler was manufactured. For example, 0104 would signify that the boiler was made in January 2004.

If your Biasi boiler is old, out of warranty, and frequently malfunctions, it may be time to consider a replacement. If you’d like to compare your options, we suggest you head over to Heatable and fill in their 90-second, anonymous questionnaire. You’ll get a range of fixed price boiler quotes for any budget.

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What’s Next?

Thanks for reading our guide to common faults codes on Biasi boilers, problems they signify, and how to fix them. If you have any questions, please leave us a comment below and we’ll get back to you as soon as possible.

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  1. beryl Barratt says:

    Biasi boiler. FL IS Coming on, how do we put it right . Thanks

    1. heatingforce says:

      What’s the pressure on the boiler? What boiler is it? For advance plus it’s a filling request.

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