Boiler - Worcester Bosch 24i RSF heating problem

generationgav

Any gas/boiler experts fancy pondering what could be wrong.

Old style Worcester Bosch 24i RSF - http://www.worcester-bosch.co.uk/cache/file/158/installation-and-servicing-instructions-for-24i--discontinued-nov-04.pdf

50% of mornings/evenings the central heating won't kick in. If it does this then hot water doesn't work either until call for heat is switched off for a few mins.

It seems to make all the correct noises, but just doesn't fire up.

British Gas been out 5 times now, serviced/checked fan, replaced air pressure switch, replaced air pressure tubes, replaced PCB. It's still not working, I think British Gas are out of ideas.

If you remove one of the air pressure switch tubes, wait for a click then reinsert this fixed the CH every time.

Once CH is on, even if it reaches temp and goes off again it has never broken down again until it has been off for many hours (6+ at a guess) generally it'll stay on for the day.

Hot water has never broken down, only when the CH fails and seems to lock the boiler to an "off" state.

We're getting BG out again, but last time they said there's "nothing" more they can do. So anything I can look for or anything it could be?

Inner_Zone

I have the same boiler in my flat. Has been a PITA over the years.

Anyway.

Firstly check the Grundfos water pump speed setting, if it is set to I the CH fails to to light regularly but if set to II is is normally OK.

Secondly the reset switch on the top panel front left, pull it up and down a few times to clean it.

Seronera

It could be a weak fan not activating air pressure switch or it could mean the venturi between the pipes needs a good clean out. Has anybody cleaned out the flue pipe. I've no idea if either of these is the problem, but that's where I'd go next if they have not been done.

Ray_Alexander

Sounds like you might be best off getting a heating engineer to take a look. Only pls check that they're gas safe approved else if they aren't - well anything could happen I guess. There's an online gas safe site where you can check.

Sorry if it sounds like an essay lol - also best tip is to get quotes as some guys charge less / more than others, so don't get stung with a higher price. There's a place I use who tend to be reasonable and don't mess around.

Ray.

Inner_Zone

generationgav wrote: »

Any gas/boiler experts fancy pondering what could be wrong.

Old style Worcester Bosch 24i RSF - http://www.worcester-bosch.co.uk/cache/file/158/installation-and-servicing-instructions-for-24i--discontinued-nov-04.pdf

50% of mornings/evenings the central heating won't kick in. If it does this then hot water doesn't work either until call for heat is switched off for a few mins.

It seems to make all the correct noises, but just doesn't fire up.

British Gas been out 5 times now, serviced/checked fan, replaced air pressure switch, replaced air pressure tubes, replaced PCB. It's still not working, I think British Gas are out of ideas.

If you remove one of the air pressure switch tubes, wait for a click then reinsert this fixed the CH every time.

Once CH is on, even if it reaches temp and goes off again it has never broken down again until it has been off for many hours (6+ at a guess) generally it'll stay on for the day.

Hot water has never broken down, only when the CH fails and seems to lock the boiler to an "off" state.

We're getting BG out again, but last time they said there's "nothing" more they can do. So anything I can look for or anything it could be?

Ray_Alexander wrote: »

Sounds like you might be best off getting a heating engineer to take a look. Only pls check that they're gas safe approved else if they aren't - well anything could happen I guess. There's an online gas safe site where you can check.

Sorry if it sounds like an essay lol - also best tip is to get quotes as some guys charge less / more than others, so don't get stung with a higher price. There's a place I use who tend to be reasonable and don't mess around.

Ray.

Did you not read the OP?

generationgav

Inner_Zone wrote: »

Firstly check the Grundfos water pump speed setting, if it is set to I the CH fails to to light regularly but if set to II is is normally OK.

Secondly the reset switch on the top panel front left, pull it up and down a few times to clean it.

Thanks for your advice!

The pump is on III and the manual advises to have it on highest; so haven't touched.

"cleaned" the reset switch - but no difference unfortunately.

It does seem to happen more the colder it is outside (I guess inside a little bit)