Need help on wiring dual zone Heat Thermostat

11 years ago

I just purchased a house with dual zone heat but whenever the 2nd floor calls for heat, the 1st floor fan kicks off also. I think something is wrong with the wiring. I've upload the pics that shows the 1st and 2nd floor wiring from the Honeywell Chronotherm III thermostat. What I see might be wrong is the 2nd floor R and Rc are wired together. Is that right? Am I missing something. The 1st floor has an extra blue wire. the white and yellow also in different place too. A breifing of my heating system. It a single gas water unit that heats the water and send hot water throughout the house, it has 2 separate blower that when it calls heat it will blow. Thanks in advance for any assistances.

Frankie

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Comments (3)

mike_home
11 years ago
The R and Rc terminals are tied together if the system has only one transform. In some system there are two transformers for heating and cooling. The R would be heating and Rc would be cooling.

The W and Y connections seem to be reversed on the 1st floor thermostat. It seems someone intentionally changed the wiring. What happens if the 1st floor calls for heat?
frankie_l
Original Author
11 years ago
The 1st floor is fine when it calls for heat, the 2nd floor's fan doesn't kick in. It's the 2nd fl when it calls for heat, the 1st fl fan kicks in and sometime blows cold air making the 1st fl even colder until it calls for heat. Something has to be wrong with the R and Rc. Just can't figure it out. Since the 1st floor R and Rc has separate wiring, why shouldn't the 2nd fl too? If so, what wire should be connected?
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harlemhvacguy
11 years ago
Its really hard to diagnose wiring problems without seeing where the wires from stats are going to. With first floor t-stat off does 2nd floor heat when turned on? It looks to me that 2nd floor Y and W are swapped but whithout knowing what they are hooked to it is anybody's guess.