Drop in combi pressure - worcester bosch

[elgar]

Im a newbie, so please be patient. My Worcester bosch boiler loses pressure, dropping to zero every 3-4 days. I top it up to 1.5. bar . Pressure drops even when heating not in use in summer. Ive checked radiator valves, and overflow pipe, but no water apparent. We are just about to take floorboards up.
Every time I top it up, I get a message F7 “ Flame detected even though appliance switched off” according to manual. This can just be reset.
Central heating/water works fine when pressure is zero, and we don’t get error messages until we top up system. This has gone on for over a year. There are no signs of leaks (stains on ceilings etc), but cant think what else it could be. Please advise.

 

[nickso]

what model?

 

[gavinda]

If its a real hassle to take up the boards, you could try using some fernox leak sealer 1st but from the sounds of the pressure drop i dont think that it would help.

 

[clf-gas]

I'll have a pound on a 24i junior.


Not a crystal ball, experience

 

[elgar]

its a RD532i, according to the book. Im really clueless as to how the CH system works, and as we arent using the heating, only hot water, didnt know whether it could be anything other than a leak (wishful thinking). As its been going on so long, thought we would have seen evidence of a leak.

 

[holty]

more like a rebaged greenstar HE.could try isolating the boiler overnight then this will rule out heating circuit or boiler.

 

[glasgowgas]

I'll have a pound on a 24i junior.


Not a crystal ball, experience

take that pound to any kids charity of your choice,sir View media item 11691 View media item 11691 View media item 11691

 

[nickso]

hmm, i can never remember the BG boiler numbers but if its the one im thinking of it could be the heat exchanger passing to condensate in the very worst case.

as holty said, isolate the boiler overnight, the later worcester iso valves are pretty good at not leaking.

 

[gavinda]

bang on nicksoits a bg greenstar.

 

[OilLecky]

I'd check the Pressure Relief Valve before ripping up floor-boards. There should be a pipe from the boiler that goes through the outer-wall ending with just an open pipe, hopefully pointing downwards. If the Pressure Relief Valve is letting by, the water will drain out of this pipe. Put a balloon over then end of the pipe, top the pressure up and wait.
IF the PRV is OK and if your system has any isolating valves in then the next move is to try to localise any leak. (I once had a similar fault. I asked the customer if they had any plumbing done recently. "Yes, a new bathroom." The plastic pipes to the new radiators went down into the new concrete floor and came up as copper pipes! The concrete floor was nice and warm! A couple of isolating valves allowed me to prove my suspicions.0

 

[elgar]

How do I isolate the boiler? (sorry, this is all new to me)- really grateful for all suggestions. Ill try the balloon idea aswell- thanks.

 

[OilLecky]

I do oil boilers but hopefully I can help. There is probably a row of isolator valves on the pipes coming out of the lower side of your boiler. Check in your manual to see which is which or look in the following website to find your boiler.
http://www.worcester-bosch.co.uk/ho...ued-boiler-literature/discontinued-gas-boiler

You need to isolate the central heating system by closing both the CH "flow" and "return" isolator vales to see if you still have the problem or if the leak is in the central heating side. (Don't forget the balloon trick though as my £1 is on the Pressure Relief Valve!)

 

[clf-gas]

I'll have a pound on a 24i junior.


Not a crystal ball, experience

take that pound to any kids charity of your choice,sir View media item 11691 View media item 11691 View media item 11691

Concider it done Glarsgi

Now where is that crystal ball

 

[clf-gas]

bang on nicksoits a bg greenstar.

He'll be bang on with his diagnosis as well Gavi

Took me two days to find this on one I had as I had to get cust not to use for 24 hours. she was topping up every day or so.

 

[gavinda]

i'd like to hear back from the op on this one then as i've never heard of this fault....

any other boilers this can occur on?