W (white) controls the auxiliary heating elements. Y (yellow) controls the compressor on the cooling system. G (green) controls the fan. C (blue or black) provides a return path to the transformer.
Where does the blue wire go on a Honeywell thermostat?
The Blue or C Wire
C wires or varying colors apply to every thermostat, but blue C wires belong to thermostats attached to a heat pump. Blue wires are for heat pumps. This wire connects to terminal B on your thermostat.
What do the different color wires mean on a thermostat?
This is the most typical thermostat wiring style, and it applies to systems that regulate both heat and air conditioning. The wires are typically arranged as follows: red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common (although the common wire may be a different color).
What is B on a Honeywell thermostat?
The O/B terminal is for heat pump systems and is used for the reversing valve. When the “O” option/position is selected the reversing valve defaults to the heating mode. If the “B” option/position is selected the reversing valve defaults to the cooling mode.
What are the wires on a thermostat?
Thermostat Wiring Tips
The W wire is connected to your heating system. The Y wire is yellow and connects to your air conditioning compressor.The G wire is green and connects to the fan.Rc and Rh: The red wire(s) are the power source for your thermostat.
Why is there a jumper between R and RC?
Effectively there isn’t a second RH wire, although there is an RH terminal. However, the heating still needs to be controlled, so a wire known as a jumper is connected between the RC and the RH terminals so that power gets to the heating control part of the thermostat.
What are the 5 thermostat wires?
5 Wire Thermostat Wiring (Any HVAC Device – Air Conditioners, Heat Pumps, Furnaces, etc.)
Red wire for power (24V).White wire for heating (connected to W or W1 terminal).Green wire for fans.Blue or yellow wire for cooling (connected to Y).Black wire for “C” or “Common” wire.
What is the G wire?
G-wire – Fan, usually green. Y-wire – Cooling, usually yellow. W-wire – Heat, usually white.
Why does my thermostat only have 3 wires?
If you have a heat-only system, you may notice that your thermostat has three wires—R, G, and W. In this scenario, the Power Extender Kit (PEK) is not compatible. There are three options available to create a C wire and make the ecobee compatible.
What is G wire on thermostat?
G: The G terminal controls the fan relay and is responsible for turning the blower fan on and off automatically or manually via the thermostat.
What happens if you wire a thermostat wrong?
Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.
What are S1 and S2 wires on thermostat?
S, S1, S2: These wires run directly outside and provide outdoor temperature information to the thermostat.
What is the Y2 wire on a thermostat?
Y2 is the thermostat wire for second stage of cooling. Y wire is for the first compressor (air conditioner units) and Y2 wire is for the second compressors (air conditioner unit). Y2 wires apply only if you have two air conditioner compressor units running from one AC thermostat.
