24/7 call-out service

Have a question?

Biasi Boiler ER05 Fault Code

The Biasi fault code ER05 related to the fan which we include Q & A or require an engineer for an emergency boiler repair.


The Biasi Fault Code ER05 Error Common Q & A

Just below, we have a list of common questions relating to the ER05 fault code on the Biasi Boiler.

Biasi Boiler ER05 Fault Code Error
  • What does the ER05 fault code mean on my Biasi boiler?
  • What does the fan do on my Biasi boiler?
  • If the ER05 fault code is being displayed on my boiler, will resetting it fix the problem?
  • What’s the most likely reason the ER05 fault code is showing on my Biasi boiler?
  • If the fan speed is too low, will I need to upgrade?
  • How will my boiler engineer know if connections and wiring are to blame?
  • How will my boiler repair company know if the fan is broken?
  • If I need a new fan to fix the ER05 fault code, how much is it going to cost?
  • What could have caused my boiler’s fan to fail?
  • When identifying the cause of water damage in a boiler, where should my engineer be looking?

What does the ER05 fault code mean on my Biasi boiler

If your Biasi boiler develops a problem, you’re going to see a fault code on the display panel. When you see the ER05 fault code, it means that there’s a problem with the fan.

What does the fan do on my Biasi boiler

In terms of safety, the fan is one of the most important components in your appliance. In fact, the printed circuit board (PCB), the part that controls all parts in your boiler, will want to see that the fan is working, before it allows the boiler to ignite.

During combustion, your boiler creates a range of harmful waste gases. Some of these are condensed, which flow out of the condensate pipe. The others are taken from your property via the flue.

It’s the job of the fan to create a large enough draught so that these gases can escape from your boiler and therefore your property, via the flue.

If the ER05 fault code is being displayed on my boiler, will resetting it fix the problem

The reset function on your Biasi boiler isn’t designed to, and won’t, fix any problem on your boiler. Your boiler isn’t working because it’s in a locked out state. In general, this happens when the boiler recognises that something’s wrong (likely, due to a reading from a sensor). If the boiler wasn’t to lockout, it’s likely that if damage has been caused to components, further damage would be caused by the boiler continuing to operate.

In the case of the ER05 fault, it’s likely the lockout has been implemented as a safety precaution. The air pressure switch has noticed that on start-up, the air pressure change isn’t correct. Feeding that signal back to the PCB, the PCB locks out the boiler.

Resetting the boiler won’t fix the problem, and if the reset was to get the boiler to work even for a minute or two, it could be dangerous.

So, don’t try to reset your boiler. Instead, speak to a Gas Safe boiler repair company. Once they highlight and fix the problem, they’ll reset the boiler on your behalf; this will clear the ER05 fault code from the display panel.

What’s the most likely reason the ER05 fault code is showing on my Biasi boiler

Your boiler repair company needs to start testing the fan to determine what the problem might be. It could be a range of things including:

  • The fan speed is too low
  • Loose or damaged wiring and/or connections
  • Faulty fan (replacement needed).

If the fan speed is too low, will I need to upgrade

If the fan speed is too low on your boiler, you won’t need to upgrade the fan. Your boiler engineer can test to check that a low speed setting is what is causing the issue. If it is, they can adjust the fan speed.

A low fan speed is going to cause a range of issues. To start, it’s going to mean that the air pressure switch notices the change in air pressure isn’t great enough when the fan fires up. That’s effectively telling the PCB that the fan’s lack of ability to vent harmful gases could mean that the boiler is dangerous.

Secondly, backdraft can cause the pilot light to go out, or mean that flame signal fluctuates. There should be a strong and constant draught out of the flue. With a fan on a low speed, any small gust of wind could be blown into the flue and cause and ignition related fault code to show on the display panel.

How will my boiler engineer know if connections and wiring are to blame

Electrical issues aren’t just common, they’re hard to diagnose. Your boiler repair company will need to test the integrity of all wires and connections. Any sign of loose connections, or the slightest damage to wires could mean than the communication between the fan and PCB isn’t at its optimum.

A lack of communication is going to mean the PCB thinks the fan isn’t working, even when it is. Ultimately, as a safety precaution, the PCB will lockout the boiler until the communication has been restored.

Not all electrical issues are going to be diagnosed visually, in fact, very few are. Instead, your boiler engineer will want to test all aspects of the fan’s wiring using a multi-meter. Loose connections can then be secured, and wiring repaired.

How will my boiler repair company know if the fan is broken

Not all problems relating to the ER05 fault code are a quick fix. If your boiler engineer has tested wiring, connections and checked fan speed and found no problems, the next item to check is the fan.

They’ll use the same multi-meter to test the fan. If the fan has failed, a replacement is going to be needed.

If I need a new fan to fix the ER05 fault code, how much is it going to cost

A fan replacement isn’t the worst case scenario for boiler repairs. Typically, you should expect to pay £250; prices may vary slightly depending on the exact Biasi boiler that you own.

What could have caused my boiler’s fan to fail

Besides old age, there’s one major killer of boilers; water damage. If your boiler engineer doesn’t think your fan problems relate to old-age, it is likely water damage is to blame.

If this is the case, it’s important they diagnose and fix that problem too. Otherwise, not only is the same issue with the fan going to occur again, but moisture could find its way into other expensive electronic components in your boiler.

When identifying the cause of water damage in a boiler, where should my engineer be looking

There are two common places to look for water damage in boilers; the heat exchanger and pump. Luckily, unlike diagnosing electrical problems, leaks that lead to water damage are extremely easy to locate.

The pump on your Biasi boiler is likely to leak if the seals have degraded. This might have been due to old-age but could also have been due to excess pressure being put on the pump. The pressure may have occurred due to blockages such as airlocks or heating sludge, as well as the pump being set on the wrong speed setting.

Assuming the general integrity of the pump is reasonable, the cost effective solution is to get a service kit from the pump manufacturer. However, if a replacement pump is needed, it’s likely to cost in the region of £250 to get one from a top brand, such as Grundfos.

If the pump isn’t the issue, the heat exchanger is the likely culprit. Heat exchangers leak when they crack; mostly due to limescale build-up. The problem with a cracked heat exchanger, is they’re extremely expensive to fix.

Replacement costs could be in the region of £450, so it’s advisable to speak to your engineer and see if repairing the boiler makes sense, or if the most cost-effective solution would be a replacement boiler with a long warranty.

Other Biasi boiler issues

For more boiler issues regarding the Biasi Boiler then please visit the Biasi Boiler Problems And Cures page.