No CH. Changed Synchron Motor. Still Not Working

[fouxdafafa]

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

Sure. I'll take a pic shortly. Mind you, nothing's changed in the wiring - it's been the same forever.

 

[ianmcd]

Sure. I'll take a pic shortly. Mind you, nothing's changed in the wiring - it's been the same forever.

you would be very surprised how many systems have been wired up wrong and people have used them for years without noticing

 

[fouxdafafa]

Here's the wiring.

FYI, I've just re-checked what I did yesterday. I've had the power off while I took the photo, so the valve went back to the default HW position. I've turned the power back on, CH is set to ON on the programmer, the thermostat is calling for heat but the motor is stuck at the HW position. The voltage being supplied to the motor is 77V.

 

[CBW]

The voltage being supplied to the motor is 77V.

Have you checked for any loose wiring in wiring centre or at the motor? - you might have a pinched cable at motor connection?

 

[ianmcd]

yes it has the HW off wired in, as a test, turn off the power, make a temp link between L,1 &4 on the programmer back plate, turn room thermostat to full, do not put the programmer back on, turn the power on and valve should motor to CH only and boiler should come on

 

[fouxdafafa]

yes it has the HW off wired in, as a test, turn off the power, make a temp link between L,1 &4 on the programmer back plate, turn room thermostat to full, do not put the programmer back on, turn the power on and valve should motor to CH only and boiler should come on

OK. I shall have to dig out some wire from the shed (which isn't easy if you've seen my shed currently). In the meantime, I'm back to thinking about the microswitches in the valve. I'm no expert, obviously, but I've watched JW's excellent video on YouTube

The circuit seems fairly simple. He describes the position of the microswitches when the valve is in the default HW position and then what happens when CH is requested (white and grey both live). In that scenario, if the switches are in the correct positions, then initially 230V goes though SW1, straight to the motor and the motor starts turning - there are no other components involved (until the valve gets to the far right and SW2 flips). So I'm struggling to understand why I'm only seeing 77V at the start of this process and the only thing I can think of is that SW1 is faulty so it's not passing 230V to the motor. But, according to JW's circuit diagram, there'd still be 230V getting to SW2 and effectively supplying the motor with the "stay still" voltage through that rectified circuitry. Until I manually move the lever and flip SW2, thereby activating the orange wire and firing the boiler. Does this make any sense? Not sure what I'd look for in the microswitch or how I'd test it but I'm suspicious of SW1. Does this make any sense?

 

[ianmcd]

I shall have to dig out some wire from the shed

well just mark the wires so you know which goes where and join all three together to test, then put them back where they were after you have done the test

 

[fouxdafafa]

well just mark the wires so you know which goes where and join all three together to test, then put them back where they were after you have done the test

OK will do, but I currently have "users" complaining that it's cold so it'll be tomorrow. I've done the manual lever thing to get the CH on for now.

I did have a look inside the valve again. I suppose I learnt a bit more - hadn't realised before that the manual lever only moves the valve to the mid-point, and only flips SW1. The valve has further to go to get to CH only. When only requesting CH, and having moved the valve to the mid-point with the lever, the valve then goes on to the CH position - so presumably the motor's doing that.

BTW, I've also noticed that moving the valve manually is much much easier with power removed.

 

[Harry Bloomfield]

Not sure what I'd look for in the microswitch or how I'd test it but I'm suspicious of SW1.

Use a meter with a buzzer for continuity testing...

Each one has three terminals, a common terminal (C or COM), a normally open (NO) and a normally closed (NC). With no pressure on its button, check the continuity between C an NC - meter should buzz, press button it should stop.

Connect between C and NC, then press button, it should buzz only whilst pressed.

You can buy replacement microswitches for a few pence on ebay, if you can solder, but there are numerous sizes and types. Measure the ones you have.

 

[fouxdafafa]

Use a meter with a buzzer for continuity testing...

Each one has three terminals, a common terminal (C or COM), a normally open (NO) and a normally closed (NC). With no pressure on its button, check the continuity between C an NC - meter should buzz, press button it should stop.

Connect between C and NC, then press button, it should buzz only whilst pressed.

You can buy replacement microswitches for a few pence on ebay, if you can solder, but there are numerous sizes and types. Measure the ones you have.

Thanks for that. I'd like to remove the circuit board from the valve but haven't worked out how to do it yet. I know that both switches click when moving the valve manually all the way to the CH only position (SW1 first and then SW2) but I don't suppose that tells me much.

 

[Harry Bloomfield]

I'd like to remove the circuit board from the valve but haven't worked out how to do it yet

The electrical head part is called the actuator. Over the past few decades I have repaired them numerous times, the spring return type are not easy to work on and can be very unreliable because they are under constant stress, such that always had a spare working item ready to install.

I have since converted to what is called a MOMO valve and actuator. These don't use a spring at all so under much less stress, they motor to each position as required then shut down completely and rather than back and forth, they rotate in complete circles, only in one direction. None the less, I keep a ready to install spare to hand.

 

[fouxdafafa]

The electrical head part is called the actuator. Over the past few decades I have repaired them numerous times, the spring return type are not easy to work on and can be very unreliable because they are under constant stress, such that always had a spare working item ready to install.

I have since converted to what is called a MOMO valve and actuator. These don't use a spring at all so under much less stress, they motor to each position as required then shut down completely and rather than back and forth, they rotate in complete circles, only in one direction. None the less, I keep a ready to install spare to hand.

I must admit to having lost a bit of momentum. We still have heating because I can activate it manually with the lever so my "users" are happy. I've convinced myself that the problem is with the circuitry on the PCB - whether it's a faulty microswitch or some other component - because I don't see how anything else explains the 77V (or more importantly, the lack of 230V) to the motor when CH is demanded from the default HW position. Even if I tested the microswitches and confirm the fault, I'm unlikely to be able to replace the microswitches (even if I could find exact replacements after desoldering them) without losing the ability to activate the heating in the meantime. Then my "users" wouldn't be happy. So, I suspect I'm looking at a new head/actuator - not sure whether I need a new valve also to match (the metal part). I believe that means draining the system. This would all be outside my comfort zone - once there's water involved, I'm happy to get professionals in.

 

[Harry Bloomfield]

Then my "users" wouldn't be happy. So, I suspect I'm looking at a new head/actuator - not sure whether I need a new valve also to match (the metal part). I believe that means draining the system. This would all be outside my comfort zone - once there's water involved, I'm happy to get professionals in

The heads/actuators are usually removable, held to the valve by a couple of bolts. They are also usually available as a separate replacement part, to the actual valve. Look up the actuator make and model on ebay. Its always worth having a spare actuator to hand, ready to install, for when it fails. It then gives you the chance to see if the failed item can be repaired.

I have had far more issues with valve actuators, than with any other part of my heating system.

 

[fouxdafafa]

The heads/actuators are usually removable, held to the valve by a couple of bolts. They are also usually available as a separate replacement part, to the actual valve. Look up the actuator make and model on ebay. Its always worth having a spare actuator to hand, ready to install, for when it fails. It then gives you the chance to see if the failed item can be repaired.

I have had far more issues with valve actuators, than with any other part of my heating system.

Thanks, but mine's the old style Drayton acl that doesn't have a removable actuator (well not easily) - not like the new style snap-on ones. Drayton tell me that installing the new style actuator instead means draining the system, so I assume that means replacing the actual valve part as well. Did I understand you correctly?

 

[Harry Bloomfield]

Thanks, but mine's the old style Drayton acl that doesn't have a removable actuator (well not easily) - not like the new style snap-on ones. Drayton tell me that installing the new style actuator instead means draining the system, so I assume that means replacing the actual valve part as well. Did I understand you correctly?

Yes! That's a shame..