Hi

I have an Alpha CD25C boiler that's about three years old.

I have had an increasing problem with loss of pressure, which the guy who fitted the boiler attributed to a small leak from one of the valves which he appears to have fixed, but the pressure loss has recurred a couple of times so maybe there is still a small leak somewhere on the system, HOWEVER...

On two occasions I have had a fairly major and sudden leak of about a pint of water from the boiler itself, flowing out of the very corner of the casing (bottom, front, right). On both occasions it occurred after the house had been cold for a few days because I'd been away, so the heating had been on for a long time to warm the house up again, then cooled for a while, then the leak happens. After the first time I got the guy in and he had a look at the boiler and speculated that the waste outflow had filled up because it had frozen outside. I think his explanation is nonsense, it hadn't been that cold, and certainly this morning when it happened again that wasn't the case - it hasn't been below freezing here for days.

One final clue is that there does seem to be a little water build up in the plastic pipe which carries waste (condensate I suppose) to the outside, in that if I pull it off the boiler (it's flexible) there's usually a spoonful of water in there, but perhaps this is just what collects in the corrugations of the pipe.

Please help with your suggestions! Thanks.

Jon

Leak will always show better when the boiler is cold, could be a small leak in the boiler, and the heat dries it out.

Could also be the condensate, froze or partially blocked, but if it's been off for a few days prior, as no condensate is being produced one could discount the theory.

Unfortunately you need to try and replicate the problem, that means turning it off for as long as possible.

Saying that, if it's been doing it for a while, it would be worth running a mirror around inside the boiler to check for any brown staining.

_________________
If you feel you have benefited from the Free advice given on the Forum, Please consider making a donation to UHM's Nominated charity, read all about it and donate here :

donnas-dream-house-charity-t52110.html

Could be the prv connection loose on the boiler and the exp vessel flat so when it over pressurises the water leaks out instead of going out the prv pipe

_________________
Dave

www.drlgas.co.uk

Thanks Dave and thescruff. I suspect it's the over pressurising thing but I'm now having a go running it with the condensate dripping into a bucket to see if that prevents it happening.

I wondered whether the problem was related to over pressurising, the logic being that when it stops due to low pressure it then gets very cold and when I repressurise it I wondered whether I have to put too much back in, so when it's up to operating temperature the pressure is too high. I was away working this week and the house was empty so I set the thermostat at 12 degrees day and night with the idea that it would never get so cold that the pressure dropped but never so hot that it over pressurised. I got back to the house this morning (Saturday) and it appears tha this worked for most of the week but probably failed some time last night - the house was cold but not freezing, and their was water on the floor below the boiler indicating a repeat of the leak I previously described.

Afraid I don't know how to take the cover off to check for staining, not quite handy enough to experiment with confidence, so will leave that to a professional. I'll try to get someone in on Monday to check the prv connection etc.

Jonny

Sounds more like the expansion vessel has losts it's precharge or duff.

The PRV dripping/running is an indication, assuming you are removing the filler loop.

_________________
If you feel you have benefited from the Free advice given on the Forum, Please consider making a donation to UHM's Nominated charity, read all about it and donate here :

donnas-dream-house-charity-t52110.html