Motorised Zone Valve Failure.

[f13ldy]

I have one of these:

http://www.avenuesupplies.co.uk/index.php?id=430&a...

Which I'm assuming has failed. My hot water is fine, but the central heating no longer clicks on.

On a brief inspection yesterday I pulled the lever over to manual and the heating clicks into life for 5 or so seconds before switching back off. Putting the lever permanently into manual has the same outcome.

So I guess it needs replacing. Is this going to be an electrician and plumbing job?

How much roughly to fit? I guess the system needs to be drained down, valve changed, electrician to wire up. 2 hours labour at the most?

[Bill]

You could just change the motor, it's marginally more complicated than changing a plug.

[Dogwatch]

I would have thought you could just change the electrics without disturbing the plumbing.

[RegMolehusband]

If it's anything like the similar looking Danfoss zone valve on our system that I've had to change 6 times in 10 years then it just detaches from the top of the valve. There's no plumbing involved just a few electrical connections (turn off the power supply!!).

[andy43]

From briefly looking at one of these in a plumbing place, it could be same as the Honeywell V4073.
When you hold the lever in manual, keep it there (might be a detent in the casing to keep the lever in manual/open?) and see if the heating continues for more than 5 secs - if it doesn't, it's a fault elsewhere.
eta yes you've tried that. Unlikely to be related to the valve/switch - it's either supplying power to the boiler or not. If you feel confident use an electrical screwdriver to check the power in/out of the valve - with the cover off you'll see a switch that 'makes' when the valve opens - that just sends power back to the boiler telling it to fire.
If that stays closed and live when the switch is switched, fault is elsewhere.

Edited by andy43 on Monday 3rd May 11:21

[Ferg]

Sounds like the motor.
Tower valves are rubbish.

[Ferg]

andy43 said:

When you hold the lever in manual, keep it there (might be a detent in the casing to keep the lever in manual/open?) and see if the heating continues for more than 5 secs - if it doesn't, it's a fault elsewhere.

That's not actually the case.
When the lever is pushed over to 'manual' and hooked there the valve cam isn't actually contacting the microswitch. If you 'thrash' the lever across, the flywheel action of the motor will allow the cam to continue across and fire the boiler, but it'll come back to the point at which it's hooked and leave the switch open.

[Eggman]

Remove the tin cover and get an assistant to turn the room thermostat up and down (with the heating turned on) whilst you watch the valve. You should see the motor operating a big cogwheel that works the valve.

Sounds like you may have another fault somewhere if the heating only runs for 5 seconds - possibly the room thermostat itself.

[Gingerbread Man]

You can buy new motors. Those Tower heads are the same fitment as the Honeywell heads. No need to touch the plumbing, just turn the boiler power off at the fuse switch spur - programmer should go out.

Change the head.

[sparkythecat]

Gingerbread Man said:

You can buy new motors. Those Tower heads are the same fitment as the Honeywell heads. No need to touch the plumbing, just turn the boiler power off at the fuse switch spur - programmer should go out.

Change the head.

Got a link to a supplier?

I'm in the same boat. Last time I'd a failure, I had to buy the complete valve just to get the motor....

[Ferg]

sparkythecat said:

Gingerbread Man said:

You can buy new motors. Those Tower heads are the same fitment as the Honeywell heads. No need to touch the plumbing, just turn the boiler power off at the fuse switch spur - programmer should go out.

Change the head.

Got a link to a supplier?

I'm in the same boat. Last time I'd a failure, I had to buy the complete valve just to get the motor....

I don't think I'd change a powerhead these days. There's not a vast difference in cost and the valve bodies are not without problems. Go into any plumbers merchant and you'll get a synchron motor off the shelf.

[f13ldy]

Managed to get a central heating engineer out today.

Replaced the motor only with a honeywell version.

[Ferg]

f13ldy said:

Managed to get a central heating engineer out today.

Replaced the motor only with a honeywell version.

That's quite a good move. Honeywell's motor is still made by Synchron, but it's to a higher specification than most.

[fatboy b]

My CH packed up last night for the same reason. A bit of percussive maintenance sorted it for now. I also cycled it a dozen times to hopefully free it up. It was fine this morning.