5 Biasi Boiler Faults [And What you Need To Do Next]

By | 5th December 2017

Welcome to our 3-minute guide to the most common Biasi boiler faults.

In our 3-minute fault finding guide we’ll cover some common symptoms that lead to boiler faults, and what you need to do next to fix the problem.

Before we go any further. Gas appliances should be worked on by Gas Safe engineers. If you need a boiler fixed or want a quote for a replacement, you can get that done here.

#1 – Boiler Won’t Ignite

Fault finding a boiler that won’t fire up isn’t particularly easy. Because, there’s 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, this takes flue gases 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. By not working (or expelling flue gases), the air pressure senses it’s unsafe to fire up, and the boiler will lockout.

#2 – No Hot Water

The first thing to check when there’s no hot water, or no heating, is the diverter valve. A faulty diverter valve can cause issues like:

  • 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 flicks into the heating or hot water position, to direct water to radiators, 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.

Stuck one side or the other would explain why you get hot water, but not heating (or vice versa).

Radiators that are half heating up when hot water comes on, could signal that it’s 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 it’s no longer stuck.

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

#3 – Red And Green Lights Are Flashing

Different Biasi boilers will display signs of faults in different ways. So, always check your owner’s manual to check what the 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 it senses the fan isn’t doing it’s 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. Fans can sometimes seize. And, that’s enough for the air pressure switch to notice the boiler is dangerous, 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, it’s likely there’s a signal problem.

This could be sensor > fan, fan > PCB or PCB > sensor. Given all parts seem to be in working order, it’s likely wiring is the issue.

#4 – Boiler Flashes With ER 04

When a boiler starts to develop issues, it will show a fault code on the display board. Most of the time it will lock out, need to be fixed, then reset.

In this case, the Biasi ER 04 fault code relates to water. The problem is either:

  • Lack of water
  • Limited or no circulation of water

The Fix

First, check the boiler’s pressure. It should be around 1.5 bar. If it’s not, there’s a chance it’s lost pressure, or not been topped up correctly. It will need to be filled 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.

#5 – Boiler Makes A Banging Noise, Then Stops Working

Older Biasi boilers can develop strange noises, a lot of the time this is banging.

If your 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. This could be blocked jets, or carbon build-up.

But, it 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 quickly be able to determine the problem.

A burner that is clogged full of carbon is easy to spot. If this is the case, this can be cleaned out.

Once cleaned, the boiler can be reset and this should clear the fault code on your Biasi boiler, so it’s operational again.

What’s Next?

Ready to get the problem fixed, or want a quote for a new boiler? Get help from qualified local professionals here.

And, thanks for reading our 3-minute guide to Biasi boiler problems.

If you have a question, drop a comment below and we’ll reply as soon as possible.

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