Replaced Motorised Valve motor but valve still not working

[wrightyintheafternoon]

Hi

I noticed I wasn't getting hot water, so manually opened the motorised valve so would get flow when CH was on until I could get a new motor.

I have a Honeywell metal motorised valve and replaced the syncronous motor with a universal Drayton motor. It fitted fine, but has not solved the problem.

I have a Drayton cylinder stat, and used to be able to hear the valve operate as I upped the temperature on the cyclinder stat, but this is not happening, so I am assuming that replacing the motor did not fix the problem.

Any thoughts on what might have happened.

How to I check the cyclinder stat is working, its an old mechanical unit and clicks OK when operated manually. I think there are two wires from the stat, that goes to a choc bloc in a terminal box that connects with the motorised valve.

 

[Garfeild]

The valve itself may have siezed or stuck,if you remove the complete actuator,assuming its a removable one,you should be able to operate the valve with your fingers,it may have a new motor,but if the valve is stiff,it may not be able to open it.

 

[D_Hailsham]

I have a Drayton cylinder stat, and used to be able to hear the valve operate as I upped the temperature on the cylinder stat, but this is not happening, so I am assuming that replacing the motor did not fix the problem.

I take it you have two valves, one for heating the other for hot water - like this.

View media item 11762
If you can't hear the motor, the cylinder thermostat is not supplying voltage to the motor. Get hold of a multimeter and check that there is 240v between brown and blue valve wires when the stat is turned to max. If no voltage, check that 240v is getting into the cylinder stat. If that is OK the cylinder stat is faulty.

 

[Tipper]

Sometimes, well almost always actually, changing the motor doesn't cure the problem because it is often the gears and/or auxiliary switch in the head that fails and not just the motor.

A new motorhead complete should fix it assuming you don't have any wiring problems too.

I learnt the hard way to always recommend a new 'motorhead' if asked because it guarantees a reliable repair whereas fiddling about with the motor and its tiny wiring doesn't. Cheap it may be, reliable it ain't.

 

[wrightyintheafternoon]

I have a Drayton cylinder stat, and used to be able to hear the valve operate as I upped the temperature on the cylinder stat, but this is not happening, so I am assuming that replacing the motor did not fix the problem.

I take it you have two valves, one for heating the other for hot water - like this.

View media item 11762
If you can't hear the motor, the cylinder thermostat is not supplying voltage to the motor. Get hold of a multimeter and check that there is 240v between brown and blue valve wires when the stat is turned to max. If no voltage, check that 240v is getting into the cylinder stat. If that is OK the cylinder stat is faulty.

To confirm, System is S Type with 2 motorised valves. CH Side working OK

Did a voltage check and I am not getting 240v across the Brown and Blue. Then turned off the power supply to boiler circuit and did continuity check across same wires to check thermosat switching. That worked OK.

Bit of a loss now as to why this has happened.

Circuit has not been changed, boiler is Glow worm 18 HXI using their integral programmer and options board, Boiler was fitted about 12 Months ago. Boiler was serviced about 2-3 weeks ago. CH side of circuit is working fine. Can't under stand why there is no voltage to the hot water circuit.

 

[griggs]

[quote="wrightyintheafternoon";p="1455813]

To confirm, System is S Type with 2 motorised valves. CH Side working OK

Did a voltage check and I am not getting 240v across the Brown and Blue. Then turned off the power supply to boiler circuit and did continuity check across same wires to check thermosat switching. That worked OK.

Bit of a loss now as to why this has happened.

Circuit has not been changed, boiler is Glow worm 18 HXI using their integral programmer and options board, Boiler was fitted about 12 Months ago. Boiler was serviced about 2-3 weeks ago. CH side of circuit is working fine. Can't under stand why there is no voltage to the hot water circuit.[/quote]

I take it there was a hot water demand from the programmer and cylinder is not full of hot water

 

[wrightyintheafternoon]

[quote="wrightyintheafternoon";p="1455813]

To confirm, System is S Type with 2 motorised valves. CH Side working OK

Did a voltage check and I am not getting 240v across the Brown and Blue. Then turned off the power supply to boiler circuit and did continuity check across same wires to check thermosat switching. That worked OK.

Bit of a loss now as to why this has happened.

Circuit has not been changed, boiler is Glow worm 18 HXI using their integral programmer and options board, Boiler was fitted about 12 Months ago. Boiler was serviced about 2-3 weeks ago. CH side of circuit is working fine. Can't under stand why there is no voltage to the hot water circuit.

I take it there was a hot water demand from the programmer and cylinder is not full of hot water[/quote]

Yes system programmer is in constant mode and cyclider stat turned up.

 

[griggs]

It sounds like the cyl stat.

Depending on how yours has been wired the valve should be:-

>Grn / Yell Earth
>Blue Neutral
>Grey Perm Live
>Brown Call from Cyl stat
>Orangle S/L to boiler


On your cyl stat, test that you have 240V on the common

 

[wrightyintheafternoon]

It sounds like the cyl stat.

Depending on how yours has been wired the valve should be:-

>Grn / Yell Earth
>Blue Neutral
>Grey Perm Live
>Brown Call from Cyl stat
>Orangle S/L to boiler


On your cyl stat, test that you have 240V on the common

I put a meter across Brown and Blue and did not get a 240V, but Cylinder stat switches across brown and blue when testing continuity

 

[griggs]

You need to confirm that you are getting a call from the programmer to the cyl stat by seeing if you have 240V on the cyl stat common.

What cyl stat do you have? How is it wired?

 

[wrightyintheafternoon]

You need to confirm that you are getting a call from the programmer to the cyl stat by seeing if you have 240V on the cyl stat common.

What cyl stat do you have? How is it wired?

Drayton 3 wire brown/blue/ground

Wire to junction box with brown connected to Motorized Valve
Brown and Blue connected to Red Live Feed from Mains. There are other feeds on valve, but not sure what they do.

 

[griggs]

If you trace the flex from the cyl stat back to the wiring center and remove the lid from the wiring center.

Be careful as there is mains voltage.

I will guess that

>the brown wire from the cyl stat will connect to the call from the prog.
>the blue wire from the cyl stat will connect to the brown of the m/v

There will also be a terminal where all the neutrals are joined together.

If this is correct. With the programmer calling for hot water, in the wiring center test between the neutral terminal and the cyl stat brown wire terminal for 240V