S plan,

[stani]

Just rewired a c/h zone and hot water zone into an S plan, due to an excess of wiring from old systems, and the pump running 24/7.
however, client has said rads got hot on hot water only,may be crap in c/h valve not allowing it to fully shut, but just wondering if I need to add the c-/h closed wire to the system, S plan doesn't normally require this but I have seen it somewhere.
It is a Glowworm ultimate 100 ff with internal pump overrun, a 22 mm Honeywell 4043 for h/ w and a 28 mm 2 port for heating, ( sorry cant remember number) Honeywell cylinder stat and no c/h stat. So at the moment it is linked out.


does anyone know when the. C/h close wire would be used.

 

[mountainman]

Only on the older style 'power on', 'power off' valves.

Spring return valves are just 'power on to open', 'power off to close'

 

[Leo21]

Could it be a badly piped common return flowing down the heating?

 

[stani]

No, think it more like muck not allowing valve to fully close,will find out more tomorrow, and let forum know,