my cdi keeps loosing presure, sometimes it will be ok for weeks and other times i have to top it up from 0 bar to 1.5 bar within 9 hours, is this a common problem and what do i do?

denis, February 2011

Yes its a common problem. First tie a bag over the pressure relief pipe [should go to outside] to see if the water is leaking from the valve. If it is, then, inside the boiler, the expansion vessel [red] has an air valve like a car tyre valve. Take the cap off and press the valve. If you get water the expansion vessel is U/S and needs to be changed. If you get nothing or just a little air then pump it up to .75bar with a bike pump. You will need to change the pressure relief valve if it has been opened.

triffid, February 2011