"John Rumm" wrote in message
...
Bart C wrote:

I have a pressurised CH combi boiler, the system pressure has gone up by
around 2 bar over the last few weeks.

Bleeding the radiators reveals pale water that seems to have some tiny
air bubbles.

Any ideas what's causing this? And can I just keep bleeding to get the
pressure down? The boiler hasn't minded working at 3.5bar or so, so far.

The problem will be that the pressure release valve will open shortly, and
these don't always reseal correctly. You then have a drip outside. Also it
suggests you are continously introducing fresh (i.e. oxygenated) water
into the system that will dilute the inhibitor and cause corrosian.

Is the filling loop still attached to the pipework? If so remove this and
check the filling tap is not letting by a constant trickle of water.

Disconnected this and there is a leak from the inlet service valve of about
1 drop every 10-15 seconds.

If that's the cause then it's amazing such an innocuous looking drip should
pressurise my CH system.

Thanks for both your replies.

Bart