seven zone wiring problem Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[brian22]

I have a problem with a heating system wiring
The system has four time control units two Randal 103e and two Randal 102e the two 103e each control a five wire Honeywell two port motorised valve via a room thermostat
The two 102e each control a five wire motorised valve on a DHW system and also a five wire motorised valve on a heating zone via a cylinder thermostat and room thermostat respectively.
The pump and boiler are then supplied from the micro switch in each valve the live for the micro switch is taken from the clock feed to each valve.
The problem arises when one zone is switched on it will not let the heating zone valve close even when the clock is on the water only setting. All the hot water valves are operating normally.
Will I have to fit relays on the control wires from the micro switches to the pump and boiler so that they work individually.

[sparx]

from your description it should not require relays since the micro switches in each valve should prevent back feeds.
I would be looking for a wrong connection in a stat. also are all valves the same part number as some honeywell valves have internal links which although the core colours are the same the valves switching is different, if you have odd sized valve eg. most 22mm & one 28mm look there first.
Interesting set up, you're not in S.Kent I suppose? I would love to get me teeth into this one!!
regards SPARX