We have a Drayton wireless for our central heating, and a Drayton ZA5679-2 2 Port motorised valve also for heating.
Our hot water side works fine.
Occasionaly when heating is called for, the sliding switch on the motorised central heating valve will not move to allow the valve to open to allow the boiler to fire up. nothing happens, no noise as if the valve is trying to open.
After about an hour this problem will go, I call for heat, the slider moves, valve will open and the boiler fires up. we have heat.
While this problem is happening we can manually move the slider on the valve actuator which opens easily the valve opens & boiler fires up. all will then work as normal.
This problem can occur if the boiler is already alight for hot water.
Where does the signal come from to tell the actuator/valve to open. I don't want to replace the actuator if the problem is elsewhere.
The wireless receiver looks like it is doing all the right things, green light will come on when heating called for.
If anyone has any suggestions as to where the problem might be. I would be grateful.
The gas valve on our boiler sometimes makes a chuntering noise just when the pilot light comes on just before firing up, a plummer has said this is not connected to the above problem.
I am in all day with heating on, 95% works as it should.
Thanks in advance.

Diane, December 2010

This sounds very similar to problems reported on another thread for this website: http://www.howtomendit.com/answers.php?id=49588 Worth checking out as one suggestion is the replacement of a small component in the receiver (£2~3) rather than the purchase of a new receiver (~£60).

AndyBB, December 2010

Thanks carefree for your reply. that sounds like it could be the problem. I am not an electrician so I would have to rely on a plummer/ electrician to check the wiring & as it is an intermittent problem it proves difficult to have someone here when it is not working. If it is as you say a fault with the relay from the wireless receiver, would it be sensible to just get a plummer/electrician to fit a new receiver or is there a chance it could be loose wiring from the receiver which could be fixed or could it be some problem elsewhere.something else? I guess as the room thermostat makes the green light come on the signal is reaching the receiver OK so no need to change the batteries? Any advice please.

Diane, December 2010

It sounds like an intermittent fault with the relay of the wireless receiver, when calling for heat from the room thermostat.
You need to check for mains voltage coming out of the unit (the power comes out of terminal 3), I have had this on numerous occasions recently.
Test when it's working and they'll be mains voltage, when it doesn't work, they'll be no voltage even though the green light is lit.

Carefree, December 2010