I want to replace a trailer thermostat that has 3 wires to a honeywell 4 wire thermostat . The problem is that the old wire has 3 wire (1w, 2r & 3 orange) the new one calls for 4 wires but wh
I want to replace a trailer thermostat that has 3 wires to a honeywell 4 wire thermostat . The problem is that the old wire has 3 wire (1w, 2r & 3 orange) the new one calls for 4 wires but when hooked up the ac does not come on
Heating & Cooling - Honeywell - Electronic Programmable Heat/Cool Thermostat - CT3300A100...
Answers & Comments
If there are both an Rc and Rh terminal, there should be a jumper across the two if there is only ONE transformer supplying power to both the furnace and the a/c. Without the jumper, there is no power on the cooling side of the thermostat.
Also, the Honeywell thermostat may require a fourth wire for the C terminal. Some thermostats 'rob' control power for their operation off of the R terminal wire and others must have the physical connection to the C terminal, and yet others have batteries for the programming portion and when they go dead, there is no heat or cool operation.