drayton motorised valve MA1

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I need to replace this valve on my heating system. The model reference shown on the plate attached to the valve only states "MA1". It is a 3 position valve feeding HW and CH.

Can someone confirm that the model MA1/679-3 offered by Screwfix is a direct replacement?
 
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Yes it is a direct replacement. If the fault is simply the actuator, as it often is, (the electric head) then just change that bit. Push the black button in and lif tthe top off.
 
Thanks for your response - bought a replacement today from Screwfix for £55.

Problem was that the motor had died on me. Pulled the unit apart without any problem. Next time I will just replace the motor - cost about £6

I have uploaded some of the photos of the innards.
 
I'd drain the system and replace for a Honeywell valve. Those Drayton valves are of poor quality.

Mr. W.
 
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You can often get away with a motor change but sometimes the gearing is a mess. The Honeywells may be better but they fail too.
 
My Drayton MA1 valve was making a regular click,click, clicking noise so a bit of surgery was called for. Also there was heat leaking to the first rads. on the system when the valve was on Hot Water only.
I drained down and removed the valve body and it was really filthy inside. Got that all nice and clean and back in it went. The actuator head had a failed micro switch ( the orange tipped switch was just limp and wouldn't click in and out). These switches were hard to find but I got some, soldered a new one in and now all working just as before.
If anyone has got as far as me and gave up because they couldn't locate any of the switches then leave a note on here and I'll give details of how you can get them.

Alan
 
Yes it is a direct replacement. If the fault is simply the actuator, as it often is, (the electric head) then just change that bit. Push the black button in and lif tthe top off.
Apologies for bumping this thread, but it closely matches my issue in that I've bought the exact same replacement part from Screwfix (head only, £55) and changed the wires one by one, like for like, with almost everything is working bar the valve springing back after there is no call for heat.

The actuator valve stays at H, and this is true until I power-cycle the system - at which point it springs back to W, where it stays when I turn the system back on until there is a call for heat.

We got here because we had a new heat pump installed six months ago and all was good, yet recently we were not getting heat. Turn out the actuator wouldn't move, but the brass fitting moves by hand, and provides heat when manually triggered using the level underneath - great. Fit a new actuator and we're golden. No, of course not, it rarely is that straightforward!

I've done some (very late night!) research just now which has led me here. As I understand it...

- Power applied to white wire moves to the mid position (hot water and heat)
- Power to both white and grey, the valve moves to H (heat only)
- No power equals W (hot water only, default 'sprung-back' position)

Please can someone confirm that I have it right in my mind?

The issue I now have is that despite there being no call for heat, hours either side of any W or H schedule in the Nest app, the valve remains at H long after the pump stops running meaning that ultimately the radiators won't stop providing heat, hence I am up now - we're all sweating buckets!

I think I have just learnt that:
- If the pump runs on, the actuator would ordinarily remain in the last position.
- The pump is wired to the boiler, not the stat (Nest 3rd gen/Heat Link by the way)
- When both W and H are not being called, the actuator would, without power, spring back to W

Again, am I on the right track, please?

I'll read voltages tomorrow and get some further data, however may I ask - does this smack of a common problem? Are you thinking "oh this dude has wired X and Y incorrectly, the noob", is there a chance I've quite literally crossed wires, which is obvious to you?

Any and all help appreciated, it's off for now and I will get more info in the morning!

I was in the process of drawing up the schematic as it will help me in future, so I have a decent idea of what's what and where it was wired before I started, although that's not to say it should go there and it was ever right!!

Thank you in advance!!
 
despite there being no call for heat, hours either side of any W or H schedule in the Nest app, the valve remains at H long after the pump stops running meaning that ultimately the radiators won't stop providing heat
The comment on this Schneider video suggest that this is actually a common issue, and has to do with switches.


As a sparky in training, I will have a look inside the housing tomorrow, too.
 
Apologies for bumping this thread, but it closely matches my issue in that I've bought the exact same replacement part from Screwfix (head only, £55) and changed the wires one by one, like for like, with almost everything is working bar the valve springing back after there is no call for heat.

The actuator valve stays at H, and this is true until I power-cycle the system - at which point it springs back to W, where it stays when I turn the system back on until there is a call for heat.

We got here because we had a new heat pump installed six months ago and all was good, yet recently we were not getting heat. Turn out the actuator wouldn't move, but the brass fitting moves by hand, and provides heat when manually triggered using the level underneath - great. Fit a new actuator and we're golden. No, of course not, it rarely is that straightforward!

I've done some (very late night!) research just now which has led me here. As I understand it...

- Power applied to white wire moves to the mid position (hot water and heat)
- Power to both white and grey, the valve moves to H (heat only)
- No power equals W (hot water only, default 'sprung-back' position)

Please can someone confirm that I have it right in my mind?

The issue I now have is that despite there being no call for heat, hours either side of any W or H schedule in the Nest app, the valve remains at H long after the pump stops running meaning that ultimately the radiators won't stop providing heat, hence I am up now - we're all sweating buckets!

I think I have just learnt that:
- If the pump runs on, the actuator would ordinarily remain in the last position.
- The pump is wired to the boiler, not the stat (Nest 3rd gen/Heat Link by the way)
- When both W and H are not being called, the actuator would, without power, spring back to W

Again, am I on the right track, please?

I'll read voltages tomorrow and get some further data, however may I ask - does this smack of a common problem? Are you thinking "oh this dude has wired X and Y incorrectly, the noob", is there a chance I've quite literally crossed wires, which is obvious to you?

Any and all help appreciated, it's off for now and I will get more info in the morning!

I was in the process of drawing up the schematic as it will help me in future, so I have a decent idea of what's what and where it was wired before I started, although that's not to say it should go there and it was ever right!!

Thank you in advance!!
This ingenious valve will remain in whatever position it was in, (apart from mid position) its known as the last port of call, if it was on CH then even if the CH & the HW are switched off the "HW OFF" will provide 230 V to the grey wire to keep the valve in the CH only position. The really clever part IMO is that DC current is supplied via a diode when the valve is in mid position and the motor just stops in this position against spring tension because "like poles attract", there is also a small demagnetizing (AC) current supplied at other times.
 

Attachments

  • Y Plan Wiring Schematic.gif
    Y Plan Wiring Schematic.gif
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  • Honeywell Mid Position Valve Schematic.gif
    Honeywell Mid Position Valve Schematic.gif
    20.3 KB · Views: 142

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