Worcester 28CDi Combi - pressure rising?

It could hace one of the following problems.
1. Filling loop passing through the isolation valve try disconnecting the braided hose if the isolation valve & check
2. The expansion vessel is flat. the vessel is a flat round cylinder usually at the rear of the boiler it will have a screider valve like a car tyre. Drain the boiler attach a footpump to the valve and recharge the vessel to 0.75bar. Fill back up and test that the pressure stays at about 1.5bar on the boiler pressure gauge.

Richard
February 2009