Every day (for about 2 years) when the heating is on, I have to let water into my Worcester combi greenstar 28i boiler system. It drops to 0 again by the next morning. The pressure relief valve looks dry (i can't reach it to feel if it is wet) but there are no drips or water stains down the outside wall. No leaks have appeared in the downstairs flat (i have been waiting for a leak to appear). The radiators aren't leaking. The pressure rises fairly quickly once the heating goes on, but it never goes into the red. I therefore assume the PRV doesn't blow and that it is unlikely to be faulty, especially if I don't see water outside. Does the expansion vessel need replacing? If the diaphragm in the EV is punctured, then surely the pressure would build up very quickly and it would blow out of the relief valve. I would see the gauge go into the red and also notice water outside, so assume it isn't the EV either. Therefore I am unsure what is causing the pressure to drop and where the water is going. I have had 3 plumbers who don't really know what to suggest other than to wait for a leak to appear (hence 2 years of observing) or to try changing the EV or the PRV and see if that solves it. Would love advice on what the problem might be before having to incur anymore cost.
Urgent advice needed!
- Thread starter Lowri
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Diehard
In Remembrance
In case you haven't seen this video.
Did you contact the manufacturer for there trouble shooting suggestions?
It's easy enough to check the Expansion vessel, so you may as well check that to eliminate one possibility.
When and if you find out what the problem was, please let the forum know.
Having to fill it frequently you must have some idea as to the quantity of water leaking. What's your guess?
mike fiore
Well-Known Member
sounds like the auto fill is failing. is it integral or outside the unit
Thank you for the video link. Very helpful and I think it more or less confirms that I don't think it's the PRV or the EV. The last plumber re-pressurised the system but it dropped back to 0 over 2 days. It's difficult to know the exact amount of water but I would say perhaps 100ml a day.
That's interesting, although I don't think there is an auto-fill. I manually fill it up to 1 bar again using the filling key.
mike fiore
Well-Known Member
Common fault 1: Low boiler pressure
The Cause: If you’re done all the usual checks (including checked the radiators for leaks and looked at the pressure relief valve without finding any faults), it could be the automatic air vent. You’ll be able to tell by taking off the plastic bottom panel and seeing if there is rusty water.
The Fix: This is usually just a case of dropping the pressure, pulling out the retaining quick release pin, and replacing the air vent. Then all we’d need to do is refill the system and test.
The Cause: If you’re done all the usual checks (including checked the radiators for leaks and looked at the pressure relief valve without finding any faults), it could be the automatic air vent. You’ll be able to tell by taking off the plastic bottom panel and seeing if there is rusty water.
The Fix: This is usually just a case of dropping the pressure, pulling out the retaining quick release pin, and replacing the air vent. Then all we’d need to do is refill the system and test.
Diehard
In Remembrance
Yeah looking up this system, it doesn't appear to ever be equipped with an auto fill. This is in the UK.
Thank you. I was really hoping this might be the answer as I haven't checked this (although I presume all the plumbers would have done) but no, no rusty water. I'm really scratching my head with this one!! Do I replace the EV and/or PRV when I suspect there may be nothing wrong with them just to eliminate it is those? Or do I do nothing and continue to wait for a leak to appear?!
Haworthplumbing
Member
Isolate the boiler from the piping system and pressure up system to 60psi and observe is there is a drop. Be sure relief valve isn't going to get subject to this pressure as it will pop. If it drops you know it's on system side. You could then isolate the boiler and test it to 60 psi as well. Again remove the relief valve and cap for testing. The higher pressure will make the leak show up easier
If you haven't seen any sign of leakage in 2 years that gauge shouldn't drop any. Could it possibly be a bad gauge? Like
suggested check all your bleeders on the finn tube and make sure none of them are bubbling any.
suggested check all your bleeders on the finn tube and make sure none of them are bubbling any.
