No CH. Changed Synchron Motor. Still Not Working

[fouxdafafa]

Had this problem before with a Drayton acl 3-way valve - the type that doesn't have the removable head. HW works but CH doesn't. Can force CH on by pushing the lever to the right to the CH setting. In the past, changing the motor has fixed this issue. This time it hasn't. I've checked the inputs - on the CH-only setting, white and grey inputs are both 230V, but the motor doesn't seem to be turning at all, or at least it's not turning the valve. Slightly worrying - I've checked the voltage supplied to the motor and it's only 70V ish. This voltage check was done with the motor in situ so I assume the check is valid. If it is indeed only 70V then I'm guessing that's why it won't turn the valve. There's a small vertical circuit board inside the housing but as I understand it it's pretty simple (a microswitch or two, a couple of resistors and maybe a diode) so I'm not sure why 230V input results in 70V to the motor unless something has blown. I don't know if there's a way to remove the board to examine it. So basically, I'm hoping for clues as to what's wrong, and whether my conclusion about the voltage is correct - and if so, why the drop. BTW, moving the lever manually takes a LOT of pushing - don't know if that's normal.

 

[ianmcd]

70V is normal in some situations with your valve, post a pic of the wiring of your programmer

 

[fouxdafafa]

Really? Would you mind explaining?

Do you mean a pic of the wiring of the LP722 (behind the removable front?), or the box in my airing cupboard that has a ton of wires and terminals (the one where the grey and white inputs come from)?

Sorry - so many questions!

 

[CBW]

If you’re struggling to move the manual leaver, and the motor is struggling, it might suggest to me a blockage of some description?

 

[fouxdafafa]

If you’re struggling to move the manual leaver, and the motor is struggling, it might suggest to me a blockage of some description?

Yes, it's really difficult to move the lever - if I push hard I can move it really, really slowly and eventually get there. I don't know how powerful the motor is (4W or something?) but I can believe it would struggle. It could be that the old motor was OK after all. I just went for the obvious quick (and relatively cheap) fix which has worked in the past. Given how hard it is to move, that's why I wondered about the low voltage - but maybe 70V is correct (although the motor requires 230V, no?).

 

[ianmcd]

Really? Would you mind explaining?

Do you mean a pic of the wiring of the LP722 (behind the removable front?), or the box in my airing cupboard that has a ton of wires and terminals (the one where the grey and white inputs come from)?

Sorry - so many questions!

yes remove the LP 722 with power off and post a pic of the wiring , it is only 2 small screws underneath the programmer

 

[fouxdafafa]

yes remove the LP 722 with power off and post a pic of the wiring , it is only 2 small screws underneath the programmer

Will do, but it'll be tomorrow. Thanks for your help and goodnight.

 

[Harry Bloomfield]

The way those motors work, is that with 230v applied they move/turn. Once they arrive at the required position, the voltage is reduced to 70v which is not enough to allow them to move, they are just able hold their position against the spring at that voltage. That is what they are designed to do.

 

[ianmcd]

The way those motors work, is that with 230v applied they move/turn. Once they arrive at the required position, the voltage is reduced to 70v which is not enough to allow them to move, they are just able hold their position against the spring at that voltage. That is what they are designed to do.

Im impressed Harry boy you are getting it

 

[fouxdafafa]

The way those motors work, is that with 230v applied they move/turn. Once they arrive at the required position, the voltage is reduced to 70v which is not enough to allow them to move, they are just able hold their position against the spring at that voltage. That is what they are designed to do.

Thanks. Thing is, I don't think the motor is ever getting 230V to move it from the HW position - even when white and grey inputs are both 230V. Although I will have to check that tomorrow to make sure. Could that be a microswitch issue, if the motor is just "holding" at the HW position?

 

[Harry Bloomfield]

I remain less than impressed!

 

[fouxdafafa]

I remain less than impressed!

I'm impressed (and grateful) that any of you are responding at this time of night!

 

[Harry Bloomfield]

Thanks. Thing is, I don't think the motor is ever getting 230V to move it from the HW position - even when white and grey inputs are both 230V. Although I will have to check that tomorrow to make sure. Could that be a microswitch issue, if the motor is just "holding" at the HW position?

It does not need to hold at the HW position, that is the default unpowered position, but worth checking the microswitches anyway.

 

[fouxdafafa]

It does not need to hold at the HW position, that is the default unpowered position, but worth checking the microswitches anyway.

Yes, I understand that it's the unpowered position - took me a while to get there. Clutching at straws I suppose, wondering why it won't move from that position.

 

[ianmcd]

because you need a HW off signal which is why I asked for a pic of your programmer wiring