Fixed one issue, got another!

[ch70]

OK, I posted last night about my boiler not starting. Was as expected, the fan had seized up. Had an engineer out this morning who took it out, lubed it up, spun it slowly with a drill and got it working again.

So now we have heat and water again, well sort of...

About 3 years ago we had our zone valve replaced, it's a Honeywell V4073A. It was done in the summer and we didn't really test it properly. Anyway, it seems that it has never worked properly. Our heating control is quite old, it's a switchmaster unit and basically has buttons to turn the heating on/timed/off and the water on/time/off.

If you set the heating or water to on it works OK. If you switch the heating AND water on, only the heating seems to work. The valve does appear to move when you switch between them but I'm wondering if there might be a wiring issue causing the valve to no open to the correct position when both are set to on.

Any ideas?

 

[D_Hailsham]

we had our zone valve replaced, it's a Honeywell V4073A.

The V4073A is a mid position valve, not a zone valve. Have you given the right number?

If you set the heating or water to on it works OK. If you switch the heating AND water on, only the heating seems to work. The valve does appear to move when you switch between them but I'm wondering if there might be a wiring issue causing the valve to no open to the correct position when both are set to on.

Assuming you have a mid position valve the wiring is like this:

 

[ch70]

oops, yes it's a mid position valve! Sorry about that

Will see if I can work out where the wires are all coming from!

 

[D_Hailsham]

Will see if I can work out where the wires are all coming from!

You may find it helpful to read Mid-position valve working and Diagnostics

 

[ch70]

Thanks for the info, will take a look. cheers.