Boiler Pressure

[Simon Man]

Hi there I hope you can help. My boiler keeps loosing pressure and has been doing so for a few months. There is no sign of leakage in the pipes upstairs and no water has been seen coming through the floor or walls. The downstairs pipework is under the floor so it could be there but I’m not sure if there is a water leak. The pressure normally sits at 1bar and when I turn on the heating it can go up to 3 bars and at times even higher. When I then turn off the heating it then can go down to Zero bar. The other day I turned it on and the pressure gauge was flicking really fast , going mad! The way it loses water is inconsistent. To start with it can lost a bar of pressure in a day and I had to refill it, but other days its stable for a few days and can hold pressure then goes to zero after about a week. Sometimes I put the heating on and it holds pressure but other times its goes to zero in a few hours. Any ideas what the issue is please??? Could it be a failure of the expansion valve and resulting damage to relief valve? Does anyone have any suggestions? Many thanks!!

 

[sbgasman]

Your expansion vessel needs recharging, do a search there’s lot of explanations on here

 

[Simon Man]

sbgasman
Many thanks! It also happens when the radiators are not on , could it also happen when the hot water is being used? I just want to avoid ripping up the floor boards if I can diagnose it!! Thanks for your help!