Boss Therm 2 port valve

[andyandy2]

Pump seems to be working ok, i've checked it, hot water is working as normal when on on its own, when heating is switched on it works normally for a few minutes, just as rads start to get warm and then something seems to switch it off, after 5 or ten mins it will fire up again and run for another few minutes, which is why i wondered about thermostats,

 

[jackthom]

When the CH next packs in and orange is no longer LIVE can you check the voltage on the brown lead to the valve?

If that's LIVE and orange isn't the CH valve is faulty.

 

[andyandy2]

The heating has just gone off while i've been watching the motor, pump stops running valve closes, loose power to orange wire, but brown wire remains live,
So is this the microswitch thats at fault rather than the motor ?
It doesn't appear the heads can be changed on these valves otherwise i'd change them over to confirm,

Thanks for all your help guys
Thanks for the wiring diagram kev, useful for future reference, and i might fit a room stat

 

[jackthom]

if you can see the valve is definitely closing when brown is live it's more likely the motor in the valve that's giving up.

Just make absolutely sure the blue neutral connection to the valve is solid before throwing it away.

 

[andyandy2]

I don't understand the switching on and off business, running for a few mins etc, its as if its being switched on /off, (it couldn't be anything to do with the programmer could it )

 

[jackthom]

The programmer supplies the live to the brown wire and that in turn should hold the valve open whenever the heating is on.

If you place the multimeter across the valve brown and blue wires and get mains voltage between them, the programmer is doing its job.

 

[andyandy2]

Ok thanks jack for all your help, i'm sure you could think of much better things to do on a Sunday afternoon, much appreciated, so it looks like a new valve or motor is needed, and my initial thoughts (guess lol) wasn't far out

 

[andyandy2]

Just an after thought, if the valve was jammed open should the heating then work ? Although if the orange wire loses its feed then the pump would need another feed

 

[jackthom]

It's possible that holding this valve wide open could operate the microswitch and get the boiler going, but from what you've said earlier I doubt it.

The only really safe way to get a bit of temporary heating in the house might be to jam open the CH valve and then use enough hot water to keep the boiler fired up.

 

[andyandy2]

I've jammed the valve mechanism fully open, the lever doesn't seem to take it to its full travel (maybe its worn ) with 2 screwdrivers, and the rads are getting nice and hot looks like new valve needed tomorrow, (looks like i might have to drain system don't think the head will come off)

Thanks again for all the help

 

[jackthom]

Excellent. You might do well to replace it with the Honeywell version.

V4043H 1056.

The dimensions are in the product brochure PDF and I'd be surprised if it didn't fit in the same gap.

http://www.uk-plumbing.com/honeywell-2-port-zone-valve-v4043h-1056-22mm-p-1410.html