I have problem with CH not coming on. I have tracked the problem to the 3 port valve (L&S MAV322). I've checked the two micro switches and these are OK. If I activate them with blade of screwdriver they turn on the CH. I've removed the Synchron motor and tested it - it works OK when connected to mains directly. There is power on the PCB for the motor. I have checked with meter and it's 240v. However it won't power the motor. When I check voltage with motor attached it is about 120 - 130v. Do I have a problem on the PCB? Can I get a replacement PCB for this model valve? Any help welcome.
CH won't come on - motorised valve problem?
- Thread starter illshaw
- Start date
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No both micro switches are OK. I have checked them.
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All the wires are live as they should be. The problem is that there doesn't seem to be the current to turn the motor. The motor does work as I've tested it remotely off the valve and also I've tried a new motor. I've checked the wiring for the motor and the live does show 240VAC when CH stat is calling for heat. However when I connect the motor, the voltage drops to 120v. No problem with the actuator arm.
where are you putting the multi meter when you get this reading from the motor ?
Across the two orange wires that feed the motor.
Valve spindle may be too stiff for motor. Remove actuator head off the spindle. You can test spindle for stiffness and you can also try head while off the spindle. The quadrant should move to CH only position, it should also trigger the 2nd microswitch and light boiler, proving the fault is valve rather than the head
sounds like your loosing the neutral to motor somewhere in the valve
thats what i was thinking along the lines of the neutral failing when motor under load.
is the neutral for the valve tight ?
If all the wires are live the valve should have motored to CH, if it hasn't motored you shouldn't get power on the orange, I would, after noting which wire goes where, remove the valve head and check power at wiring centre. If all correct with all the HW and CH on/off combos I'd replace the valve head.
Gents - I'm following this thread with much interest given that I'm experiencing a very similar problem with a 3-port mid-position Honeywell 4073A.
To be fair I've not checked whether there is voltage on the white wire though I am curious to know where do you go next if there is not voltage on it?
At the moment the valve requires manual intervention i.e a push to the "open" setting before the CH will come on. HW is fine.
I'm not sure whether the actuator head can be removed from the valve itself in my case, but any suggestion would be welcomed. In the meantime and not wishing to hijack the thread, I look forward to hearing what happens next!
Cheers
Andy
To be fair I've not checked whether there is voltage on the white wire though I am curious to know where do you go next if there is not voltage on it?
At the moment the valve requires manual intervention i.e a push to the "open" setting before the CH will come on. HW is fine.
I'm not sure whether the actuator head can be removed from the valve itself in my case, but any suggestion would be welcomed. In the meantime and not wishing to hijack the thread, I look forward to hearing what happens next!
Cheers
Andy
if you have no power on your white wire then you need to go to the wall stat and check thats getting power and sending power.
head can be removed on honey well unless it is really old in which case it cant and you can tell as you will see a red seal between head and body
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