Ariston eurocombi A/23. DHW intermittent. Heating fine. Pressure was at 3 bar. Lowered to 1. Boiler now comes on for longer when on demand for hot water, but can hear a clicking from around the gas valve (solenoid maybe ?) Turn hot tap off, boiler runs continously with no demand on for heating or DHW and rads warm up.
The only way to stop boiler running is to switch off at the boiler on/off switch. Never come across this one yet.
Cmon htg engineer & co help me out here boys.