Which Wire Color Is Cool On Signal For A Thermostat

Ever follow the thermostat manufacturer's instructions whenever irresolute the thermostat. Always plough the power off at the air handler and the condenser and make certain at that place is no voltage at the transformer before proceeding.

Furthermore, the thermostat wire colors beneath are the most likely colors used for most installations; however, your thermostat wire colors may be different than what the indication is here. There is no official standard for thermostat wire colors. Additionally, thermostat wiring colors are not standardized. However, these are the most wiring methods used based on my years of experience in the HVAC field, where I successfully wired a lot of thermostats and as recommended by manufacturers and common sense for thermostat wiring colors code.

For instructions on how to wire a thermostat, please run across how to wire a thermostat page. Refer dorsum to this folio for thermostat wire colors.

Thermostat Wiring Colors Code - High Performance HVAC Thermostat Last Designations

Before proceeding, nosotros highly advise that y'all plough the power off at the circuit breaker. Furthermore, the power for both the condenser and the air handler/furnace. Y'all may cause a expressionless curt in the control excursion. Additionally, that could potentially cost y'all a service call for troubleshooting and repair.

Thermostat Wire Colors Code | HVAC Control

Thermostat Wiring and Wire Colour Nautical chart – Thermostat Wiring Colors Code
Tstat Terminal Designation	Color of Wire and Termination
R – The R terminal is the power. Information technology is a red wire and comes from the transformer commonly located in the air handler for split systems, simply you may find the transformer in the condensing unit of measurement. For this reason, kill the power at the condenser and the air handler before irresolute or working on the wiring at the t-stat. Lastly, if y'all take a parcel unit, then the transformer is in the package unit.	Red Wire for the R terminal - *Yous should exist aware that this may have inverse, especially if the person who wired the thermostat didn't utilize conventional color coding.
RC – The RC concluding is designated for the power for cooling. Some HVAC systems employ 2 transformers. A transformer for cooling and a transformer for heating. In this instance, the power from the transformer in the air workout organization would go to the thermostat terminal. Furthermore, it should be noted that a jumper can be installed betwixt RC and RH for a heating and cooling system equipped with a single transformer.	Red Wire for RC terminal. *Although be aware that this may accept changed, peculiarly if the person who wired the thermostat didn't use conventional colour coding.
RH – The RH last is designated for the power for heating. See RC above for an explanation. It should be noted that a jumper can be installed between RC and RH. Finally, this is merely for heating and cooling systems equipped with a unmarried transformer.	Ruddy Wire for RH concluding. *Although exist aware that this may have changed, especially if the person who wired the thermostat didn't employ conventional color coding.
Y – This is the terminal for cooling or air conditioning and goes to the compressor relay. Typically a thermostat wire pull is made to the air handler on split systems. This wire is so spliced for the separate wire pull which is made to the condenser. Furthermore, some manufacturers put a terminal board strip well-nigh the control board in the air handler. Therefore, a splice is non needed.	Xanthous Wire for Y Terminal. *Although be aware that this may take changed, especially if the person who wired the thermostat didn't use conventional color coding.
Y2 – This is the final for cooling 2d stage if your system is then equipped. Finally, many systems just accept a single compressor but if yous accept two compressors (or a ii stage compressor) which should only operate off of i thermostat then you need the Y2 thermostat final for 2nd stage cooling.	*The near common colour I've seen used for this final and wire designation is light blue, simply this varies and is entirely up to the installer what color to use. Furthermore, for the thermostat, wiring colors code for this last (if equipped) consult with the installer. Finally, if that is not possible, then trace the wire out to the source.
Due west – This is the last for heating. This wire should go directly to the heating source whether it be a gas or oil furnace, electric furnace, or boiler or auxiliary heating for a oestrus pump.	White Wire for W Concluding. *Y'all should be aware that this may take changed, specially if the person who wired the thermostat didn't employ conventional color coding.
W2 – This is the concluding used for second stage estrus. There are gas furnaces with low fire and high fire and some depend on control from a two-stage heating thermostat with a W2 terminal. Estrus Pumps use staging for auxiliary heat and need a W2 terminal.	*The most common color I've seen used for this terminal and wire designation is a brown wire, but this varies and is entirely up to the installer what colour to utilize. Furthermore, for the thermostat, wiring colors lawmaking for this final (if equipped) consult with the installer or trace the wire out to the source.
G – This is the final used for the fan relay to energize the indoor blower fan. Furthermore, on a divide system the blower fan is in the air handler. A package unit of measurement the blower fan is in the outdoor package unit.	Greenish Wire for Thou Concluding. The fan wire. Furthermore, *be enlightened that this may have changed, particularly if the person who wired the thermostat didn't use conventional color coding.
C – This is the terminal which originates from the transformer and is necessary to consummate the 24 volts power circuit in the thermostat but only if the thermostat consumes electricity for power. Finally, many digital thermostats require 24 volts for ability, so the mutual wire is necessary.	C stands for common, and at that place is no universal color used for this terminal, although black is the well-nigh common colour I've seen. For the thermostat, wiring colors code for this final (if equipped) consult with the installer. Finally, if that is non possible, then trace the wire out to the source.
O or B – These terminals are for heat pumps and the B t-stat last is used on for Rheem or Ruud and whatsoever manufacturer that energizes the reversing valve in heating way for the heat pump. Furthermore, other manufacturers of heat pumps utilise the reversing valve for cooling. The O thermostat final is for this purpose. This wire goes to the outside heat pump condenser, for reversing valve control. Finally, this is for rut pump thermostats.	Orange Wire for O and Nighttime Bluish Wire for B, depending on the installer of the heat pump and the manufacturer. If you have a Trane, Carrier, Goodman, Lennox, Ducane, Heil, Fedders, Amana, Janitrol, or whatsoever other manufacturer other than Rheem or Ruud, yous will exist utilizing the orangish wire for reversing valve. Lastly, Rheem and Ruud will usually use the bluish wire for the reversing valve.
East – This terminal is for rut pumps and stands for Emergency Heating. Furthermore, if for whatever reason the rut pump condenser fails and information technology is necessary to run the heat there is an option on oestrus pump thermostats for emergency heating. The E last activates the redundancy heat source.	E – There is no universal color used for this terminal designation, only this should be wired straight to the heating relay or the E terminal on a concluding stripboard in the air handler or package unit if you accept a heat pump package unit.
X or Aux – This terminal is for back-up on a rut pump and allows for auxiliary heating from the dorsum-upward heat source usually located in the air handler.	X or Aux – There is no universal color used for this terminal designation. However, this should exist wired direct to the heating relay or the Aux terminal on a final stripboard. Information technology is terminated in the air handler or package unit if you have a heat pump packet unit.
S1 & S2 or (Outdoor ane and Outdoor two) – Some tstats have this terminal. Furthermore, these are for an outdoor temperature sensor. Special shielded wire is used for this run and completely dissever from the other thermostat wires. Finally, some manufacturers volition show this the T terminals on their thermostat.	Using shielded wire prevents electromagnetic forces generated from other wires from interfering with the signal within the shielded wire. A remote temperature sensor is a solid-state device. Furthermore, the betoken needed to go an accurate temperature is sensitive to electromagnetic forces from another wire within the structure. Finally, this blazon of wire is different from the typical thermostat wire and a separate wire birthday.

Thermostat Wiring Colors Lawmaking | HVAC Command - Tabular array of wire colors along with explanations and exceptions. Standard Wiring Colors - or Standard Wire Colour per Industry Norms

Wiring Color Chart for Air Conditioners and Oestrus Pumps

typical wire colors

Tracing a Wire to the Source

Terminal Strip in an Air Conditioner Air Handler If you lot find the colors are non matching to the convention described hither, you can always trace to the source. Furthermore, merely if you are confident in your skills. Replacing an old thermostat with a new thermostat tin can be daunting and so brand certain to follow all thermostat wiring instructions. Lastly, follow the instructions on our How To Wire a Thermostat page for many swell tips such as: Take a picture of the old thermostat wiring before you lot unwire it.

Furthermore, the wire colors on the transformer will be different than the thermostat wires. If you lot do non know what you are doing, then please call a professional. Importantly, there are a few reasons for this:

First, as mentioned, there is high voltage in the equipment and tin can be hazardous to your health.
Lastly, if you wire it wrong or accidentally touch the incorrect wires together, you lot can blow the transformer.

Furthermore, either reason can exist harmful.

Additional Resource

Also, check our thermostat category for other detailed articles on thermostats. Additionally, it includes other detailed pages about the thermostat wiring color lawmaking.