Procombi 85 HE with solid red light

[Jonrobx]

Hi,

I have a Procombi 85 HE that has been installed for around 4 years. I'm having a problem where the solid red light fault indicator is showing and the boiler is shutting down.

This happens when water and heating is selected, usually after around 30mins. It also happens occasionally when only hw is selected.

I usually switch the boiler to off position (not at the wall) and wait a few minutes before switching it back to hw and ch when it will start working again for around 30-60mins when the problem repeats.

The boiler has around 2 bar pressure.

I've done some research online which points at thermistor and PCM faults, hoping someone on here can point me in the right direction please!

Thanks,

John

 

[Agile]

It could be overheating.

But when did you last have it serviced?

Tony

 

[Jonrobx]

Hi tony,

We've checked and the boiler hasn't been serviced for the last two years, sounds obvious that that could be the problem! I'll get it sorted then post again if I'm still having problems.

Thanks,

John

 

[Agile]

Can you look up the possible causes of that red light in the manual?

I think that it covers both overheat and ignition problems.

If its caused by the latter in your particular case then can be a problem which a proper service would deal with.

Start saving up as several parts could be needed.

Having a boiler serviced regularly helps to identify impending problems at an early stage before too much damage is done.

Tony

 

[Jonrobx]

I've checked the manual and it states that red light on solid means primary NTC open/short circuit.

What does this mean in laymans terms?

Thanks

 

[Agile]

It means that a part has either failed or become disconnected.

But before saying if it could be a DIY job to replace I would need to check in the book exactly where it is.

Tony

 

[ianmcd]

Replacing the primary thermistor is an easy enough job but unfortunately you cant do this yourself as it involves disturbing the combustion chamber, it shouldn't be too expensive to have this done by a competent engineer though, these thermistors aren't the most reliable and your boiler has 2 primary and secondary (hot water) I usually swap them out in pairs as they are not expensive and saves a second call out

 

[ianmcd]

removed double post

 

[Jonrobx]

Thanks for the suggestions, I've arranged for someone to come out so hopefully won't be too expensive. I'll post results.

 

[bladeater]

Hi

Just wondered if you got to the root of the problem with your boiler. As i am having what sounds like the same problem... and same age boiler!! would appreciate a heads up as this is in a rented property and could same a few trips back and forth!

Thanks Justin

 

[holty]

Just wondered if you got to the root of the problem with your boiler. As i am having what sounds like the same problem... and same age boiler!! would appreciate a heads up as this is in a rented property and could same a few trips back and forth!

have you thought about starting a new thread p.s are you gassafe