Central Heating

[phl666]

My HSA3 Actuator switch seems to get stuck occasionally, making the central heating stay on. If I push it to the manual position and then pull it back to auto, it seems to free itself.

Can I fix it or does it need replacing?

[KARL]

I am not clear on what the make-up of your actuator is, but it sounds as if it is one with a little motor inside it (characterised by a whirring noise as it goes off and the spring returns it to closed). If that is the case, then it is worth opening it up to test the spring action and how well the motor works. The motors are available on their own, but from your description it seems more likely the spring action is not correctly returning the thing to closed. Try it off the valve first, then if it is not returning closed without any load you could dismantle to see what is the problem. If it does close without load then the valve itself may be too stiff for the spring (try turning it by hand, but start in the closed position and note it before removing the actuator). A word of warning: some Honeywell valves cannot be dismantled while the fluid is in the system because the actuator and valve paddle are joined (or somehow the waterway is opened when the actuator comes off) so release the actuator very gingerly. Remember to have all power to the system switched off.