I have a Potterton Profile 80E which does not bump up?
I have a Potterton Profile 80E which fails to bump up when I set the heating thermostat to call for heat or run a hot tap continually. There is no pilot light but I think that is correct until it ignites when the boiler bumps up. If I move the boiler thermostat it clicks and sounds as though it is just about to bump up but doesn't.