Actuator problem?

[janners]

I've what looks likes a fairly standard Drayton Mid Position Actuator.
The problem I have is that I only get central heating when the hot water is also switched on.
The switch on the actuator does seem to move correctly.
i.e.
when all off or just the water is on the W position
when both on it is in the M position
when just heat on it is in the H position

but the boiler actually doesn't come on when just the heating is switched on -
I am thinking this is the microswitch on the actuator when in this position.
Does this sound sensible before i go ordering a new actuator?

Also the above is all I know about plumbing after an afternoon's Googling so I may well be missing something simple.

 

[Blagard]

I think you have correctly identified the problem.

Changing the micro switch is just a fiddly job and you will need a soldering iron. make sure you get the same type of micro switch for a replacement.

I would advise you test it before removal from the actuators head to be sure. If you find the micro switch to be OK test the motor and make sure that is not on it's way out. If the motor stalls just before operating the switch that would be the other possible reason.

Edit:
Oops! I see you are going to replace the actuator not just the micro switch. A better solution if you don't fancy checking out the parts.