It seems the expansion vessel of my CH system is not functioning properly. Now, I find that when the air-vent cap is loosened, as prescribed in the manual, it leaks a steady trickle of water. Anyone know what is the matter and is it going to harm the system by tightening the cap? Cheers for any help or advice.
Central Heating Boiler Air-Vent Leaking Water
Jun 23, 2006
1 Replies
It needs to be fixed, either by replacing the damaged one, or adding a new working one in addition. I wouldn't use the system until you do.
The problem is that the diaphragm within the expansion vessel is shot, so the air bubble within it can't press against the expansion of the hot water as it expands. This means the pressure rises rapidly and dumps the contents of the system out of the pressure relief valve.
Christian.
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