If I have wired up a room thermostat incorrectly (and this is quite possible!), would this have an adverse affect on the programmer/timer? Both items are Honeywell and, unfortunately, due to their ages I do not know the model numbers. By adverse affect, what I mean is, could an incorrectly wire room thermostat stop the programmer/timer from switching on/off the central heating at the set times? The room thermostat when turned down, does turn off the boiler, and likewise, when turned up, does turn on the boiler. Is the wiring from the programmer/timer some how connected to the room thermostat?