3 port MV not switching to CH

[rickmd]

hello, id like to know how to rectify a problem with my MV. My timer appears to be functioning ok as it switches on the HW as programmed, However for CH the boiler is not firing up. Originally i though thus maybe a faulty room stat, however after replacing it the problem remains.

So I set the timer to CH on, and then pulled the lever on the MV over to CH and the boiler fired up, however if i let go of the lever it pulled itself back. Do I have a faulty MY, or is it not getting the info it needs to switch over?

 

[seco services]

More likely the syncron motors failed.

 

[rickmd]

More likely the syncron motors failed.

Thanks for the reply.
Is there a test i can perform see if it is the motor and if it is, is that easy to fix/replace?

 

[D_Hailsham]

One motorized valve (left) or two (right)?

View media item 5946 View media item 11762
If just one, can you get heating when the HW is also on?

You should be able to hear the motor running when Heating is turned on. (Use a screwdriver as a stethoscope.)

 

[rickmd]

One motorized valve (left) or two (right)?

View media item 5946 View media item 11762
If just one, can you get heating when the HW is also on?

You should be able to hear the motor running when Heating is turned on. (Use a screwdriver as a stethoscope.)

It's the one on the left. A Honeywell .And yes ch does 'mostly'hot when the HW is on as well, but as we only used to have the hw on for 2 hours a day . Ch used to work better when hw was not on.
To recap...
Every time i swith heating timer on and I pull it towards me, it just moves back. I might add that pulling it towards and putting it into the little hook to keep it there doesn't seem to work because, a. It's not far enough over, and b, it moves itself out of the catch.

So do I need to replace the synchro?

 

[matt1e]

It's the one on the left. A Honeywell .And yes ch does 'mostly'hot when the HW is on as well, but as we only used to have the hw on for 2 hours a day . Ch used to work better when hw was not on.
To recap...
Every time i swith heating timer on and I pull it towards me, it just moves back. I might add that pulling it towards and putting it into the little hook to keep it there doesn't seem to work because, a. It's not far enough over, and b, it moves itself out of the catch.

So do I need to replace the synchro?

If, from the first paragragh you mean that the heating works when hw is also on then no you dont,you have a possible wiring or actuator fault
to exclude the programmer select both hotwater and heating then turn the cyl stat down
does the valve now motor to central heating?

Matt

 

[rickmd]

It's the one on the left. A Honeywell .And yes ch does 'mostly'hot when the HW is on as well, but as we only used to have the hw on for 2 hours a day . Ch used to work better when hw was not on.
To recap...
Every time i swith heating timer on and I pull it towards me, it just moves back. I might add that pulling it towards and putting it into the little hook to keep it there doesn't seem to work because, a. It's not far enough over, and b, it moves itself out of the catch.

So do I need to replace the synchro?

If, from the first paragragh you mean that the heating works when hw is also on then no you dont,you have a possible wiring or actuator fault
to exclude the programmer select both hotwater and heating then turn the cyl stat down
does the valve now motor to central heating?

Matt

When I say the ch mostly works when hw+ch are both on, I mean that just 3 of the rads near the pump come on. The downstairs rads remain cold, previously they used to get hot.
I have tried the test that you suggested, I turned down the stat on the cylinder but the motor on valve did not move to ch.

 

[matt1e]

So I set the timer to CH on, and then pulled the lever on the MV over to CH and the boiler fired up

ok I've read through properly , if when you did the above the hw was turned off, then that suggests you have power at the valve white,
so yes I'd say you need a new motor

Matt