two port valve is it broken?

[Viper Gas]

i have been called out to inspect and repair a heat only boiler with external controls such a cylinder thermostat and a two port valve. Although the boiler have live power the pump does not run becuase the grey wire on the two port valve is not supplying any power. I checked to see if the valve had power coming into it and it did and the moment i shorted out the valve ( ie made the grey wire live) the boiler fired up immediately.
if you see the attached photo am i right in assuming that the grey wire should be live if the valve is getting power on the main brown wire coming in.

basically how can i determine for sure that its the valve at fault?
gosh i hate the valves

cheers
guys

DD368

 

[Whn1]

They grey wire should be permanently live mate.

 

[Whn1]

Assuming its a honeywell oR similar, Follow it back and see if it's come loose somwhere.

 

[lame plumber]

not brilliant at valves but grey should be permanent live and orange switched live to boiler to make it work, so have a look at the wiring diagram for your s plan to see whats wrong and get your multi meter out. could be a faulty micro switch on the valve motor.

oi w1 write longer posts, then i'll get there first

 

[shaunsinky]

240 on the grey from your time clock (pl), 240 on the brown from room/cylinder stat(SW), motor opens and sends 240 down the orange to pump and boiler

 

[stoker122]

Grey = perm. Live
Brown = signal from stat
Orange = switch live to boiler

 

[shaunsinky]

i switch the power off, take the synchron out then look at the cogs on the motor. if your calling for heat and they are turning, replace the valve, if not its just the synchron itself

 

[plumber0808]

http://www.honeywelluk.com/documents/all/pdf/wiring guide issue 16.pdf

Can be quite handy. There's a fault finding part on there too.

 

[heliotrope]

It is not unknown that the orange has been wired permanant live and grey
to be switched.

This would usually be detected when testing the valve.

Whatever. Make sure the micro switch is making correctly.

 

[lame plumber]

do the honeywell course asap, youll find it useful

 

[Viper Gas]

This is how this is wired up....the orange is wired to a live , goes to the valve and then the grey should come out live to give boiler signal to fire up......the grey comes out of that little plastic microswitch on the valve ,should that become live if the valve is energised which it was on its brown wire....

It is not unknown that the orange has been wired permanant live and grey
to be switched.

This would usually be detected when testing the valve.

Whatever. Make sure the micro switch is making correctly.

 

[stoker122]

Do you know what type of valve it is?

 

[gassafe]

I normally just wire in a new 2 port head to see if that fixes it, it's always worth having a 3 port & 2 port on the van!

the valve is the most likely thing to fail I reckon, thermostats are normally pretty rare, check the programmer also tho!

 

[bewsh]

This is how this is wired up....the orange is wired to a live , goes to the valve and then the grey should come out live to give boiler signal to fire up......the grey comes out of that little plastic microswitch on the valve ,should that become live if the valve is energised which it was on its brown wire....

The wiring is wrong there... Orange shouldn't be wired to a live as orange is the switch live. Grey should go to a permanent live, brown is from the room stat/cylinder stat and then orange is switch live to boiler/pump

 

[shaunsinky]

did you get it fixed?