My (aged) CH system doesn't work properly despite despite having had everything except the boiler (which works just fine) replaced at various times. The electronic Honeywell timer/control panel, the CH two port valve, and the pump all seem to function as they should. But....
There is a room thermostat (very basic Honeywell manual dial) which I am beginning to suspect is wired up wrongly. It is set at 21°. When the heating has been off all night and then the timer calls for heat in the morning, everything works fine. When the house reaches temperature, the heating goes off - again, as it should. The problem is that then the heating doesn't come on again by itself, however cold it gets. The only thing that works is to turn the room thermostat right down - say to 10° - and leave it for at least half an hour. Then turning it back up to 21° will usually result in the boiler firing up and everything working normally until the house reaches temperature once more. Then, rinse and repeat...
I've uploaded a photo showing how it's wired (and another showing the wiring diagram inside it.
I've also uploaded a photo I found via Google of someone else's similar thermostat where the yellow and blue wires are transposed.
I want to know if this is likely to be my problem, and whether or not I'm safe to change them around myself?
It should be said that countless tradespeople have looked at our system and scratched their heads (hence my reluctance to throw more money at it). My worry is that the other bits of the system may also be wired 'unconventionally', and I obviously don't want to make an expensive (or worse!) mistake...
Can anyone help?
There is a room thermostat (very basic Honeywell manual dial) which I am beginning to suspect is wired up wrongly. It is set at 21°. When the heating has been off all night and then the timer calls for heat in the morning, everything works fine. When the house reaches temperature, the heating goes off - again, as it should. The problem is that then the heating doesn't come on again by itself, however cold it gets. The only thing that works is to turn the room thermostat right down - say to 10° - and leave it for at least half an hour. Then turning it back up to 21° will usually result in the boiler firing up and everything working normally until the house reaches temperature once more. Then, rinse and repeat...
I've uploaded a photo showing how it's wired (and another showing the wiring diagram inside it.
I've also uploaded a photo I found via Google of someone else's similar thermostat where the yellow and blue wires are transposed.
I want to know if this is likely to be my problem, and whether or not I'm safe to change them around myself?
It should be said that countless tradespeople have looked at our system and scratched their heads (hence my reluctance to throw more money at it). My worry is that the other bits of the system may also be wired 'unconventionally', and I obviously don't want to make an expensive (or worse!) mistake...
Can anyone help?