Drayton MA1 MidPoint Actuator/Valve

18 Jan 2008
Reaction score
United Kingdom
Help for female in distress...

Plumber installed new valve on CH.
Took away paperwork, including wiring diagram.
Found the wiring not correct ie CH only working when HW is on... cannot separate, so programmer effectively just working as an on/off switch.
Can anyone tell me how to wire up or provide a wiring diagram for the Drayton MA1 3 port Mid Positioon Actuator/Vale?
Kate... bet there aren't many females asking questions on this site???

:( :(
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should you not get the plumber back if its not working properly?
Does port "A" go to the heating and port"B" to the cylinder?

White c/h on
Grey h/w off
Orange boiler live and h/w on.

Its same as Honeywell "Y" plan!
Sadly, he's an older guy and not well at the minute.
Thought you all might be able to help with this minor problem!
Once I get a diagram I'll be alright with it.
Thanks for your concern.
Like the comment.
I'm sure you all can't be a load of old women!
Thanks for the offer of finding a link to follow.
Thanks for the link.
I guess it would be the same as the Honeywell Y Plan, so Ill check it out tomorrow.

You guys are brilliant,
Thanks a lot.
:D :D :D
Just wondering why the valve was changed? and was there a wiring problem before, or did previous valve function correctly at some time.
I mention this because someone (Fester n Rot) had a problem this week in a new property with similar problem. It turned out there was a wire missing between the HW OFF terminal on the programmer and the 'grey' wire of the valve. This I believe is quite a common fault so it would not be a surprise if you find the same fault.

The 'grey' wire is fed from two sources, one is from the HW OFF terminal as mentioned and the other is from the satisfied terminal of the cylinder stat. what this means is that the 'grey' gets power when HW is on but satisfied or when HW is off.
The valve was replaced because it had seized up completely.
Have now checked that the A&B Ports are connected correctly.
It does also seem that the programmer is correctly switching the valve between A, B and A/B.
The problem then seems to be elsewhere. :rolleyes: :rolleyes:

The programmer does not seem to fire up the boiler when set to just CH.
So need to now check all other wiring ie programmer, boiler, pump to see what's happening between each.

The wiring diagrams you pointed me to will be really helpful.

Wish me luck you guys!
Bye for now.
If the two wires feeding the grey of the valve are there and the valve is moving across to the CH only position and there is no output from the valves 'orange' wire to fire the boiler, then it suggests the second micro switch in the actuator head is faulty.

So pay particular attention to each of the wires mentioned, somtimes one is there but not the other ( HW OFF)

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