I have a Worcester 24CDI boiler and the pressure is at 4 when the boiler is on and goes to 3 when turned off. I have drained off water but this has made no difference. We recently had a new double radiator installed into our garage conversion and that takes over an hour to get luke warm, the old radiator in that room would get very hot asap, we have been turning the other radiators in the house off to get the water to the garage convertion radiator quicker but it still takes ages. - can anyone give me some advice please.

Edd2712, October 2008

It's at 4? And rests at 3 when the boiler's off? I'm amazed your PRV hasn't blown. Does the pressure eventually drop to zero?

That's waaay too high. Drain some out (bleed a rad or use the drain point on the boiler) til it drops to 1.5 when cold.

If the pressure creep back up, make sure the filling key is removed (or if you have a filling loop, disconnect it). If it still creeps up, you have a problem - most likely a pinholed plate heat exchanger is letting mains water into the CH system causing the pressure to rise.

BunSlinger, October 2008