I've had the above boiler since about 2001, and it's been working well. The only thing I've changed since is the pump.

A few weeks ago I notice a slow build up of pressure in the system, and I've had to routinely bleed off excess water to bring the pressure back down. My plumber suggested that there may be a fault it the filling-up loop, but after I disconnected this the problem IS still present. I would be very grateful for any thoughts on what is causing this, and what I can to do about it?

Erol, May 2008

Hi, I haven't the manula for this exact boiler here, but I will asume it is a combi.

There may be a small leak from dhw to system water across the dhw heat exchanger, this would lead to a pressure rise even if the filling loop was disconnected.

T, May 2008