ariston eurocombi a/23 runs continously

by **temps** » Fri Jul 10, 2009 7:30 pm

Hi guys,
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.

by **htg engineer** » Sat Jul 11, 2009 3:32 pm

Have you check that the DHW flow switch and CH and/or DHW microswitches aren't sticking ?

If the DHW microswitch or flow switch is sticking then the boiler will stay on, with there being no hot water demand the heat is finding it's way to the radiators.

Why was the pressure at 3 bar ?
It's either:
been topped up too much ? <<<<<<same as rosebery states below.
plate heat-ex leaking ?
expansion vessel not taking up the expansion?

htg

by **rosebery** » Sat Jul 11, 2009 4:28 pm

"Why was the pressure at 3 bar ?"

Also perhaps the filling mechanism not shut off and the PRV is holding the system pressure at iro 3 bar?

Cheers

by **temps** » Sun Jul 12, 2009 7:02 pm

cheers htg eng. your a god send. can always rely on you dude, and thanks also rosebery. was 3 bar when i arrived. filling loop slightly open. Will look at what youve suggested.

Thanks again guys

by **temps** » Sun Jul 12, 2009 7:05 pm

wot you reckon on the clicking from the gas valve. I'm sure its the solenoid but not 100%