On Sun, 30 Dec 2018 09:59:01 +0000, David wrote:

As discussed previously I suspect I have a fault in the 3 port valve.
Drayton Mid Position Actuator MA1.

For diagnostics, do I have to do more that check that when CH is called
for by the programmer power goes to the thermostat, and when the
thermostat clicks on power comes back to the valve?

I am assuming that the sequence at the valve is:

(1) CH request from the thermostat

(2) Mid port valve moves to open CH port

(3) Controller then calls for pump and boiler

This has the second assumption that if (2) fails to happen then (3) will
not happen (which seems to be more or less what is happening).

Diagnostics day tomorrow, hopefully.

Gave up on the diagnostics and changed the valve.

Quick and simple job of replacing wires like for like in the wiring loom.

It would have been easier if the wiring loom had been more accessible.

All now working as it should be, thank $Deity.

The original valve head has been battered for some reason; will post
pictures soon (if anyone cares).

Thanks to all for the help.


Cheers


Dave R


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