Vaillant Boiler F27 Fault Code - Incorrect Flame Detection
The Vaillant fault code F27 boiler incorrect flame detection Q & A or require an engineer for an emergency boiler repair.
The Vaillant Boiler Fault Code F27 Error Common Q&A
Just below, we have a list of common questions relating to the F27 fault code on the Vaillant boiler.
- What does the F27 fault code mean on my Vaillant boiler?
- What can cause a F27 fault to be displayed?
- Will resetting the boiler fix the F27 fault on my Vaillant boiler?
- Can I fix the F27 myself?
- My boiler loses pressure, will that contribute to the F27 fault being displayed?
- My boiler does lose pressure, but it’s not leaking, so what’s the problem?
- Can electrodes and ignition leads be reconditioned?
- If I don’t fix the leak, will the F27 problem reoccur?
- How do I know if the PCB is broken?
- How much does it cost to fix a broken PCB on a Vaillant boiler?
- Do I need a new boiler if my PCB is broken?
What does the F27 fault code mean on my Vaillant boiler
According to Vaillant, the F27 fault code will be displayed when there is “incorrect flame detection”.
The boiler has recognised that for whatever reason, the combination of gas supply and ignition isn’t within the boiler’s working tolerances.
When it comes to gas and ignition related faults, most modern boilers will lockout as a safety precaution.
For that reason, it’s advisable to contact a gas safe engineer to fix the problem.
What can cause a F27 fault to be displayed
There are many things that can lead to incorrect flame detection, and a F27 fault code being displayed.
Your engineer is likely to check the following:
- Moisture isn’t present on any of the internal electronic components
- The electrode and ignition leads show no signs of excessive wear or damage
- The correct operation of the PCB
Will resetting the boiler fix the F27 fault on my Vaillant boiler
Resetting a boiler can sometimes clear a fault code. But, it won’t fix the fault.
And, as boiler’s display fault codes and lockout as a safety feature, it’s not advisable to reset a boiler until a Gas Safe engineer has diagnosed and fixed the problem.
Can I fix the F27 myself
Opening a boiler’s casing is operating on a gas appliance. If you do not have Gas Safe certification, you shouldn’t be working on gas appliances. It’s not safe.
More importantly, a misdiagnosis with a F27 fault code could lead to the wrong parts being replaced at a huge expense, and the problem still being present.
My boiler loses pressure, will that contribute to the F27 fault being displayed
A boiler that loses pressure will not lead to an F27 fault being displayed directly, but it can contribute.
If your boiler loses pressure, there is a leak in the heating system.
Now, if the part that’s leaking is in your boiler (such as the boiler’s pump), there’s a chance that water has gotten into electrical components.
This moisture doesn’t have to be water dripping directly onto components.
Boiler’s and their internal components get very warm. This warmth will turn water into condensation and circulate around the boiler.
When this settles on electrical components, it can cause them to malfunction and the F27 fault code to be displayed.
My boiler does lose pressure, but it’s not leaking, so what’s the problem
The actual F27 error doesn’t have to be “moisture” related. It could be a faulty PCB.
But if your boiler is losing pressure, you have a leak somewhere. This doesn’t have to be on the boiler itself.
Any part of the central heating system that’s leaking, will contribute to a loss in boiler pressure.
A few examples of places where leaks can occur (that are not in the boiler) include:
- Faulty bleed vents on radiators and towel rails
- Pinholes in radiators or copper pipework
- Old soldered joints that are leaking
- Radiator valves
The leak itself isn’t contributing to the F27 fault, but it does need to be fixed.
Can electrodes and ignition leads be reconditioned
If your Gas Safe engineer has determined that the electrodes and ignition leads are at fault, they need to be replaced, not reconditioned.
Depending on your boiler’s model, the total cost of parts will sit in the £45-95 range.
If I don’t fix the leak, will the F27 problem reoccur
There’s a very good chance the problem will reoccur. It’s happened once, so it’s likely to happen again.
More importantly, if the issues were related to cheap parts such as ignition leads, you’ve gotten lucky.
If the water and condensation had made itself to the PCB (printed circuit board), you’d be talking about a repair bill that’s up to 5 times the price.
As well as diagnosing and fixing the fault relating to the F27 code, make sure the engineer finds and fixes the leak too. This will save you money in the long run.
How do I know if the PCB is broken
The PCB is the control board for your boiler. It interacts with all electronic components within your heating system.
Without a working PCB, you could have problems such as:
- An intermittent display panel (keeps going on and off)
- Lack of temperature regulation
- A malfunctioning pump
- Fan doesn’t kick in, so the boiler doesn’t vent gases correctly and locks out
How much does it cost to fix a broken PCB on a Vaillant boiler
As always, the price of a boiler repair comes down to two major factors:
- The model of your boiler (and therefore, the price of the PCB itself)
- The cost of labour (gas engineers vary in price throughout the country)
Realistically, you should expect to pay somewhere in the region of £400 to have a faulty PCB replaced.
Do I need a new boiler if my PCB is broken
The PCB and the potential £400 repair bill aren’t the determining factors of whether you need a new boiler.
If your boiler is under warranty, the part should be fixed for free by the manufacturer. And, this also means that your boiler is relatively new. In this case, we’d advise on keeping the boiler.
It’s when boilers go outside of warranty that it’s usually more cost effective to have a replacement boiler.
And there’s a good reason for this; if one part has deteriorated, others are likely to follow.
The best solution is to have a gas engineer check the condition of expensive components such as the heat exchanger, fan and pump. They’ll also want to check how “clean” the system is.
If your boiler is 5+ years old, has a broken PCB and has had heating sludge and limescale running around the system, it could be bad-news.
Limescale can create hotspots and crack heat exchangers. Whereas heating sludge can block up the pump.
If you don’t have a boiler filter and scale reducer fitted, there’s good chance internal boiler components are deteriorating, and a replacement is the most viable option.
Other Vaillant Fault Codes And Error
If your looking for the list of error codes relating to the Vaillant boiler then please read the article Vaillant Boiler Fault Codes And Cures