Boiler and Pump don't switch off

[Doug66]

When my timer/progrmmer switches the hot water and the heating off I can hear the motorised valves shutting but the pump and the boiler continue. This is a recent fault. Grateful for any ideas. Thanks. Doug

 

[Gas2Air]

What valves are they? One is stuck.

 

[Doug66]

Danfoss HPA2. There are 2. I can hear a whirring noise from each when I switvch the hotwater and heating on/off at the programmer/timer switch. Doug

 

[Gas2Air]

Undo 2 screws on each corner of the heating/hot water valve, pull off head if the actuator then fully closes, its the valve.

Spray some dw40 on the half moon shaped spindle, give it several turns 180 degrees make sure its free and loose. Refit head and test. These valves tend to leak and get very stiff from rust.

Could be a faulty microswitch stuck on. Then that will require a new actuator.

 

[Doug66]

Thank you. Done that. Both valves seem to be free and operating ok, I've given them a dose of WD40 too. So it must be the micro switch? Any tips on how I tell which actuator needs replacing? The HW one looks newer so I guess I could just try changing the heating one? Doug

 

[Gas2Air]

Isolate power positively. Take grey or arange wire that will be linked in junction box to the other. Keep one in. Turn power on. If boiler and pump fire, trace that wire to what actuator. If stays off, then same trace it back and change it.

50/50. Normally i'd be suspecting the CH valve this time of year after being off but you never know. Good luck.

 

[Doug66]

Brilliant! Thanks! I'll have a go tomorrow and let you know. Doug

 

[Doug66]

Thank you very much indeed for your help. I fitted a new motorised valve tonight and normality has been restored. You have been extremely helpful.

 

[Norcon]

The microswitch always fails in danfosss valves. They are rubbish and don't last much longer than a few years.