boiler not firing on HW setting

[pcrepairman]

Hello all, I wonder if anyone can help with my HW problem, CH is working fine but I have no HW, the relay on the programmer clicks and red light comes on when set to HW but boiler does not fire up, the system is quite old and all the componants seem to be honeywell, there is a thermostat on the cylinder and what I think is a 2 way valve on a pipe at the side of the cylinder, If I put the CH on and manually open the valve with the little lever underneath and click it into place leaving it open then the water in the cylinder will get hot, this will only work with the CH on and will not work if only the HW is on.

Thanks for any help in advance.

 

[Slugbabydotcom]

what I think is a 2 way valve on a pipe at the side of the cylinder

It's a zone valve and is probably faulty.

Make sure the power gets to it when you call for hot water and that the neutral wire is connected properly... ie. no neutral fault. Then either replace the head of the valve, or the full valve as required.

Normally you only need to replace the full valve if:-
1. the spindle on the brass body is hard to move
2. the valve body is leaking
3. the head is no longer available or is not replaceable

 

[pcrepairman]

Thanks for the response, I think you have solved it for me, when i turn on the HW nothing happens at the Zone valve, I will check the voltage getting to it and check the microswitch i found in there also.

Thanks again.

 

[Slugbabydotcom]

If you like playing about with stuff like that you will probably find that its the synchron motor inside which has gone. You can buy these separately and save some dosh. However if I had the same set-up and mine went I would just renew the full head as I dont trust the 'cap' type connectors you find inside.
Glad to be of assistance