Air in system and water pressure

[Stretty]

Hi,

I have moved into a house which has a combi-boiler which is around 5 years old. The house it\\\'s self is 80 years old. The boiler is wall mounted in a down-stairs room. Over the past few weeks the water pressure in the boiler keeps dropping, and on close inspection it would appear that as the water is heated it is expelled from the system through the over-flow? There also appears to be a lot of air in the system and I have to bleed the rads on a weekly basis. I am bleeding the system with the pump off, so I cannot workout where the air is coming from, as I would image it is an air build up which is causing the system to lose water pressure?

Does anyone else have any ideas?

Thanks

 

[kevplumb]

see FAQ expansion vessel

 

[Stretty]

Thanks for the info. I have had another check, and the pressure was on 0 so I increased it to 1 and the water was expelled straight out of the over flow. So I guess the Expansion vessel is broken.

Thanks

 

[kevplumb]

I increased it to 1 and the water was expelled straight out of the over flow. So I guess the Expansion vessel is broken.

sounds promising but it might just need recharging

the prv(overflow) valve will prob need renewing as well