gauge pressure

[John Paul]

Hi
I have that the pressure on my oil fired central heating has gone up from 1 bar to 2.5 bar and water is seeping from avalve on the boiler.What would have caused the increase in pressure? It is asealed system

Regards jp

[plumbbob]

Various ideas spring to mind, but without knowing the type of boiler it is a bit of guesswork.

The most obvious cause is a faulty filling loop and the valve is not shutting allowing water to continually enter the circuit causing the relief valve to operate.

[John Paul]

Good morning.

Thank you for your reply,the boiler is a 90 BTU Firebird with a reillo burner.
Would the filling loop be connected to mains at all times? and is ther any risk of explosion if boiler is used at present due to cold weather?

Rgards John Paul

[plumbbob]

Cold weather won't make any difference. Obviously, it is difficult and unwise to state a definitive answer about the safety of a device from the distance of a forum.

2.5 bar is high, but not an excessive pressure. Pressures as high as 3 or 4 bar aren't likely to pose any serious risk, but there is the increased possibility of joints and seals failing because of the unnecessary pressure. Any dangerous levels will be automatically vented by the pressure relief valve.

Theoretically, the filling loop should not be left connected because of the possibility of backflow contaminating the mains water. In reality, almost all loops are left permanently connected.

Check the pressure often to ensure it is not inching higher. Look at the difference between a cold and hot system. It will be higher when hot. Does the pressure rocket when warming from a cold start?

If you want and know how to, operate the relief valve manually to vent some of the higher pressure to drop it to about 1.5 bar.

[John Paul]

thank you for that information and you were right connection to heating system was on constant,now fixed
regards john paul

[matt00]

check expansion vessel?