Fluctuating central heating pressure on Combi Boiler

Joined
2 Aug 2010
Messages
2
Reaction score
0
Location
Lincolnshire
Country
United Kingdom
Hi
For the last few months we have had a problem with our boiler,
The central heating pressure gauge when set to 1bar can lose pressure to approx .8 but then go back up to one. Or other times continue to drop. I have checked everywhere for a sign of a leak but have been able to find nothing yet. We left the boiler off for a week and no pressure was lost. I can only presume the pressure fluctuation are caused by the air temp/weather. And the loss of pressure is a leak when its hot and expands or some valve not working correctly. I will end up having to call an expert to sort it but would prefer to have some idea of whats causing it.
Thanks

Mark
 
Sponsored Links
You need to test the air pressure inside the expansion vessel......with the system at zero pressure indicated on the gauge, check the air pressure inside the EV and set it to 10 psi as a rough figure. Use an ordinary car tyre pump for this.
If water escapes from the tyre type valve on the EV then the diaphragm within is split.
Pressurise the boiler back up to 1 bar when this is done.
John :)
 
Hi
Thanks for your quick reply.
EV - Escape Valve? Will it have its own pressure gauge on it? I haven't even take the outer housing of the boiler off I presume i will need to, to do this? I have all the docs/boiler diagrams from when it was installed.

Mark
 
Sponsored Links
The water in the system expands when it heats up, and the pressure rises.

This is perfectly normal, as long as there is no steady loss of pressure. Always check it with the system cold.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top