Honeywell V4073A valve clicking

[bertiemallards]

hi all just replaced a honeywell V4073A 3 port motorised valve, and cant seem to get it to fire the boiler when the room stat calls.
The mechanical cogs drive the arm forward but fail to make the switch cut in to fire the boiler. If i use a screwdriver to touch the switch the boiler fires.
This is the same issue as i had with the v4073A i replaced, so cant be a fault with the acutal valve?

any suggestions?

thanks

 

[seco services]

is the valve going right over to ch only poisition or only mid way ?

 

[picasso]

Did you change the complete valve or just the head ?

 

[bertiemallards]

Just replaced the head, If i remove the head so that its not in contact with the mechanical valve, it still does the same

 

[seco services]

would say you have a wiring issue.

more likely the grey wire is dead when ch only called for.
as said is it going over all the way ?

 

[bertiemallards]

By 'all the way', do you mean the mechanical arm swinging from the right to the left?

 

[seco services]

the mech arm means nothing that is only an arm to put the valve in mid position for filling draining purposes.

check the grey wire has 230v

 

[bertiemallards]

No doesnt seem to have any power there

 

[seco services]

when the heating is called for only the grey wire will become live from either the hw off position at the programmer or hw on at programmer cyl stat satisfied.
in the grey terminal will be another 2 wires 1 from programmer hw off
and 1 from cylinder stat satisfied.

the grey needs to be live to pull the valve to ch only otherwise it will sit in mid position hw/ch.

so check what one is not giving 230v programmer or cyl stat.