Drayton Actuators keep failing

[kennydies]

I bought my house about 18 months ago and discovered, after a few months, that my boiler was not switching off after the timer had gone off.

After a bit of trial and error and tracing the electic through the circuit I found that when the timer had switched off and the actuator moved into the off position, power was still being fed to the boiler.

I replaced the actuator and all was well but then it happed to the second one.

I am now on my 3rd in 18 months and last night the same thing happened.

The actuator is a ZA5, is there any reason for actuators to keep failing, either environemental, wiring or model?

This is driving my nuts now as I can't trust the boiler to switch off.

Is there any risk to the boiler firing against a closed water circuit?

Thanks, Ross

 

[misterdubya]

The system should have a bypass to prevent 'a closed water circuit'.

Drain the system, & replace with a honeywell valve. Drayton Motorised Valves are really poor quality - especially if the system is dirty.

Mr. W.

 

[nickso]

cheaper just to change the microswitch if that's the fault all the time. surprised about how often it has gone, I wouldn't say they are very poor quality either. not the best maybe but certainly not the worst.

 

[kennydies]

How can the micro switch fail so often, would have through you would have a fixed switch attached to the motorised arm which disconnects then in the off position?

how can the switch create a circuit when the arm is back?

 

[Agile]

You would have to open the valve ( not so easy ) and see if the switch is pushed in or just left actuated internally.

I suspect something in your system is taking too much current, perhaps the pump, and thats welding the tiny contacts in the microswitch closed.

Tony

 

[nickso]

it's only one screw to open the valve head.

the M/s can be seen at the bottom and the position of the switch easily seen. they fail one of two ways, the white plunger activated by the cam sticks in and holds the switch closed or the contacts weld themselves together and melt the switch.

 

[kennydies]

Thanks for this guys.

Will go home later and check the travel of the value and open the actuator and see if anything looks out of the ordinary.

I presume the microswitch is not welded shut as it is an intermittant problem that usually resets itself.

Ross

 

[mickyg]

you sure the valve is just not sticking ? the spindle on the body of the valve should free to turn by hand, if not its prob killing your motors.

 

[nickso]

also check the spring posts have not broken off. you would probably have noticed odd operation if they had though.

 

[kennydies]

mmm, checked last night (by this point it was working again)

Took actuator off, checked valve which can be turned by hand.

Opened the actuator and nothing looks out of place, although I can't actually see where the microswtich is.

I would rather something not work permanently rather than Intermitently, at least you can find the fault then.

 

[nickso]

can't miss the m/s, just follow the orange and grey wires.