My discontinued switchmaster 3 way motorised valve has 6 coloured wires and I am installing a Drayton motorised 3 way valve that has only 5 wires.
Could you please give me new wiring diagram.

G Jepson, February 2012

Hi Paul,

I saw your post which was really helpful. I too had a failed switchmaster acutuator, and replaced it with a Drayton MA1 and wired it using the original six wire cable from the programmer (Switchmaster SM400 central heating timer control) joined via a junction box to the five cables of the Drayton MA1 as described in your post above. However, when I powered everything back up, the valve stays in the Mid position, and doesn't move if I switch over to central heating&water or hot water only.

If i remove the actuator and watch it as i switch between central heating&hotwater and hot water only (on the control unit) the actuator is not moving. The valve itself moves freely by hand.

At first I thought i had a faulty actuator, so I went back to the supplier and they changed it, but the new one does exactly the same thing.


Could you or anyone else advise? I'd be most grateful.

Need4Speed, September 2012

don't bother opening the wiring center. Use a 5 pin connector or small wiring box. Isolate the power and cut off the lead to the switchmaster. On the switchmaster lead from the wiring center, connect the orange and red together. Then join this to the orange of the new valve. connect the yellow of the switchmaster lead to the white on the new valve. connect the white of the switchmaster lead to the grey of the new valve. then blue to blue and earth to earth - job done!

Paul the Gasman, February 2012