have a glowworm compact combi boiler(approx. 5yo).... constantly losing pressure ... topping up every day.... have been advised probable pressure release valve but more likely expansion vessel problem.... Can i check it . If so how do i go about it and are there any special tools required... I am quite handy and dont mind complex jobs.
expansion vessel
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All you need regards to access and pressure will be in the manufacturer's instructions. When you get to the car tyre type valve on the expansion vessel and remove the cap if any water comes out you need a replacement the diaphragm will be split. It may just require charging which is just a case of pumping it back up to the stated pressure with a normal footpump. If your pressure relief has blown and still dripping even slightly it will need replacement.
B
breezer
i am not a heating engineer, but basically expansion vessel is a ballon in a tin, it has a car tyre valve on it, press it if water comes out its had it, if not treat as a tyre, but dont blow it up to 28psi, it only goes to a couple of psi, try a search on this froum for expansion vessel
ollski said:
Just to clarify if pipe outside is dripping is it more likely to be pressure relief valve.... or is order of checking vessel first then prv second?..... thank you for your prompt responses....
Are these components expensive to replace?
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If your pipe is dripping outside you will need a new pressure relief valve because when they blow they get grit and muck on the seating and then won't seal so your pressure will constantly drop due to the leak.
You will need to check your expansion vessel as this is half air and half water, if the diaphragm has split it will be all water therefore leaving nowhere for your hot water to expand into.....down goes the cold system pressure.....fill it up.......up goes your hot pressure....pop goes your PRV.....return to beginning.
What is the system pressure when your system is stone cold compared to when it is working?, if it's a big difference like 2 bar you will need a new expansion vessel.
You will need to check your expansion vessel as this is half air and half water, if the diaphragm has split it will be all water therefore leaving nowhere for your hot water to expand into.....down goes the cold system pressure.....fill it up.......up goes your hot pressure....pop goes your PRV.....return to beginning.
What is the system pressure when your system is stone cold compared to when it is working?, if it's a big difference like 2 bar you will need a new expansion vessel.
I have similar problem too, as ollski suggested, likely problem is with the expansion vessel. I have a glow worm combi boiler 24ci. On switching on the central heating, the pressure bar rises up to 4.0, and on switching off it loses pressure down to 0, and I have to top up the pressure back again to 1 to 1.5. But water only heating does not affect the pressure.
Does anyone know how much it will cost to replace the expansion vessel? either DIY or getting an expert boilerman in?
Does anyone know how much it will cost to replace the expansion vessel? either DIY or getting an expert boilerman in?
Eggy it may not be the exp. vess the flei tube to the boiler can get blocked causing the same symptom as a faulty exp. vess You may need to change the prv as they get muck on the seating when they lift and can letby especially if you keep refilling the syst. with un traeted water
Eggy it may not be the exp. vess the flei tube to the boiler can get blocked causing the same symptom as a faulty exp. vess You may need to change the prv as they get muck on the seating when they lift and can letby especially if you keep refilling the syst. with un traeted water
Hi, the flexible braided pipe is buried deep behind the pump. How do you access it (to clean it - mine is either blocked or bent flat).
Much appreciated.
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