My central heating system refuses to heat the domestic hot water although the central heating is fine. The Drayton mid position valve tell-tale at the top remains on the left and does not move over when I select "hot water only" at the control box. I have taken off the motor assembly and can turn the spindle manually through the ten degrees required and in this way I can get the hot water from the boiler to flow into the hot water cylinder. I don't know if it is significant but even when the controls are set to "Off" for heating and hot water the motor in the valve remains red hot and only cools down when I turn the whole system off at the mains. Any ideas please?
Drayton Mid position valve
- Thread starter lewesdon
- Start date
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operate the hw/ch with the actuator removed from the valve.
you can watch the marker move as the valve operates.
hw only marker should be on W
ch only position H
ch/hw position M.
does it move to these positions ?
the valve head will remain warm when controls set to off if heating was last port of call as the motor/valve will be held in last position by the grey wire.
you can watch the marker move as the valve operates.
hw only marker should be on W
ch only position H
ch/hw position M.
does it move to these positions ?
the valve head will remain warm when controls set to off if heating was last port of call as the motor/valve will be held in last position by the grey wire.
Many thanks Karl for such a quick reply.
I've taken the motor etc. off the valve and set the control panel to H/W only and turned up the hot water cylinder thermostat. The tell-tale at the top does NOT move from it's present position on the far left and no hot water is going into the tank. I hope this is clear as I am no D.I.Y man
Anyway many thanks.
I've taken the motor etc. off the valve and set the control panel to H/W only and turned up the hot water cylinder thermostat. The tell-tale at the top does NOT move from it's present position on the far left and no hot water is going into the tank. I hope this is clear as I am no D.I.Y man
Anyway many thanks.
what are you calling the tell tale ?
the lever on the end or the marker on the side with the lettering W H M.
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Hi Karl.
Sorry I'm causing you so much trouble.
When viewing the valve in it's normal position there is a black lever which is on the left hand side of the unit. That's not what I called the tell-tale.
The one I meant is a small black plastic indicator which moves across in a slot on the top of the cover when it's working correctly. There are no letters on the one I've got but there is a little matt area where I can well imagine there should be the three positions marked but aren't. I do know that when the indicator is at the left end of the slot it indicates that the valve is set to C/H only.
I hope this makes it clearer
Best wishes and thanks.
Sorry I'm causing you so much trouble.
When viewing the valve in it's normal position there is a black lever which is on the left hand side of the unit. That's not what I called the tell-tale.
The one I meant is a small black plastic indicator which moves across in a slot on the top of the cover when it's working correctly. There are no letters on the one I've got but there is a little matt area where I can well imagine there should be the three positions marked but aren't. I do know that when the indicator is at the left end of the slot it indicates that the valve is set to C/H only.
I hope this makes it clearer
Best wishes and thanks.
right you have the right marker.
but your discription don't match up.
may be easier is you mark the letters on the casing.
look at the valve side on with the marker.
in the mid position willbe M.
the end with the black lever on willbe H.
the end with the screw for the lid willbe W.
if your looking at the side of the valve straight on W is on the left
hw not ch.
but your discription don't match up.
may be easier is you mark the letters on the casing.
look at the valve side on with the marker.
in the mid position willbe M.
the end with the black lever on willbe H.
the end with the screw for the lid willbe W.
if your looking at the side of the valve straight on W is on the left
hw not ch.
O.K. Karl I've finally got the message. Thanks for the photo.
The black indicator is in the position H which on your photo is on the right and it won't move over even when it should go to "Hot water"
It seems to me who knows very little that it might be one of two things
1) The message being sent from the control panel isn't correct or isn't being sent
or
2) The electric part of the valve is faulty in some way.
The fact that I can turn the spindle manually seems to rule out a plumbing problem
Best wishes.
The black indicator is in the position H which on your photo is on the right and it won't move over even when it should go to "Hot water"
It seems to me who knows very little that it might be one of two things
1) The message being sent from the control panel isn't correct or isn't being sent
or
2) The electric part of the valve is faulty in some way.
The fact that I can turn the spindle manually seems to rule out a plumbing problem
Best wishes.
have you a multi meter ?
No Karl but my next door neighbour has. Could you please say what he would have to test please and he would come round to help,
Thanks again
Thanks again
follow the cable from the valve back to a wiring centre
locate the grey wire.
put the programmer on hw only
check what voltage is at the grey terminal.
locate the grey wire.
put the programmer on hw only
check what voltage is at the grey terminal.
O.K. Karl
Will do tomorrow. Many thanks for all your efforts. If you don't mind please may I let you know the result tomorrow?
Best wishes.
Will do tomorrow. Many thanks for all your efforts. If you don't mind please may I let you know the result tomorrow?
Best wishes.
you'll have to check more wiring depending on the result of the grey wire.
what you can do now if you want is isolate your main fused spur for your heating system and that will reset the valve.
tell me what position the marker gos to then.
what you can do now if you want is isolate your main fused spur for your heating system and that will reset the valve.
tell me what position the marker gos to then.
Hi Karl
Thanks for the advice. There may be a bit of a delay with the voltmeter from next door so if he doesn't come around this morning I think it best to go out and buy one. Does "Digital Multimeter" sound right for the job? If so they do one of those at Screwfix. Do you need any expertise to work one?
Thanks again.
Thanks for the advice. There may be a bit of a delay with the voltmeter from next door so if he doesn't come around this morning I think it best to go out and buy one. Does "Digital Multimeter" sound right for the job? If so they do one of those at Screwfix. Do you need any expertise to work one?
Thanks again.
Hi Karl,
I am almost too ashamed to tell you what happened today. My neighbour came round with his voltmeter and checked the grey wire as you advised. He happened to pick up the actuator and a small spring and a tiny piece of plastic fell out. The bit of plastic had broken away from the main body and taken the spring with it. We came to the conclusion that this was probably been the cause of the problem all along.
I went to the plumbers merchant and bought a new valve ( including the pipework, they don't come singly) on sale or return. Back home fitted it on and thank goodness it worked!
So I am so sorry to say that I have caused you a lot of inconvenience due to my ignorance but thank you once again for all the time and trouble you have taken with my problem,
With my most sicere best wishes.
I am almost too ashamed to tell you what happened today. My neighbour came round with his voltmeter and checked the grey wire as you advised. He happened to pick up the actuator and a small spring and a tiny piece of plastic fell out. The bit of plastic had broken away from the main body and taken the spring with it. We came to the conclusion that this was probably been the cause of the problem all along.
I went to the plumbers merchant and bought a new valve ( including the pipework, they don't come singly) on sale or return. Back home fitted it on and thank goodness it worked!
So I am so sorry to say that I have caused you a lot of inconvenience due to my ignorance but thank you once again for all the time and trouble you have taken with my problem,
With my most sicere best wishes.
thats why it was staying in the ch position the spring is needed to pull the valve back to its relaxed position hw only.
you should of been able to buy the actuator on its own
you should of been able to buy the actuator on its own
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