Good afternoon all,
for a particular application I am looking for a combined central heating digital timer-controller/thermostat unit (wall-mounted), preferably mains-powered although I would consider one of those handy roving battery-powered ones if necessary...
My question relates to the wiring of the output switch. Traditionally a central heating controller has a SPDT switch providing both a "CH on" and "CH off" signal, and the pole of the switch is usually wired to live, to provide the mains supply to the zone valve, and so on.
However, I need to find a unit specifically in which the pole of the switch (and it must be SPDT, SPST) is not hard-wired to Live, such that I can wire it to something else.
Does anyone who has fitted such a unit recently know if it is usual for the manufacturers to hard-wire the switch pole to Live? Obviously for the battery-powered ones this isn't an issue but for the mains-powered controllers there is the possibility that the live power for the unit and the switch pole are connected internally, which scuppers my plans.
thanks,
Michael