Replacing Bryant TSTATBBBAC01-B with Honeywell RTH230 programmable thermostat.. I have a question about wiring

Question

The Bryant has six wires, 1 of them is for power, my new one takes batteries...

The six Bryant wires are:
White
Orange
Green
Cyan
Yellow
Red

There are 5 ports on my new thermostat:
Rh
Rc
White
Yellow
Green

The white, yellow, green are easy, but I cannot figure out where the following wires go on my new thermostat: Orange, Red, Cyan.. one of them must be for power, which I don't need. Another question... Could I electrical tape the wire for the power, since I wont need it, what which one is the power wire?

Answer 1

The batter y is usually just so the thermostat won't have to be reprogrammed after a poower outage, it still needs power to run.

R – The R terminal is the power for the thermostat. This comes from the transformer usually located in the air handler for split systems but you may find the transformer in the condensing unit. For this reason, it is a good idea to kill the power at the condenser and the air handler before changing or working on the wiring at the thermostat. If you have a package unit then the transformer is in the package unit.


Red for the R terminal. *Although be aware that this may have changed especially if the person who wired the thermostat didn’t use conventional color coding.

RC – The RC terminal is designated for the power for cooling. Some HVAC systems use two transformers. A transformer for cooling and a transformer for heating. In this case the power from the transformer in the air conditioning system would go to the thermostat terminal. It should be noted that a jumper can be installed between RC and RH for a heating and cooling system equipped with a single transformer.


Red for RC terminal. *Although be aware that this may have changed especially if the person who wired the thermostat didn’t use conventional color coding. Most installers use the color coding as noted but be aware that some do not use the thermostat color coding.

RH – The RH terminal 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 for a heating and cooling system equipped with a single transformer.


Red for RH terminal. *Although be aware that this may have changed especially if the person who wired the thermostat didn’t use conventional color coding. Most installers use the color coding as noted but be aware that some do not use the thermostat 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 and then this wire is spliced for the separate wire pull which is made to the condenser. Some manufacturers put a terminal board strip near the control board in the air handler so a splice is not needed.


Yellow for Y Terminal. *Although be aware that this may have changed especially if the person who wired the thermostat didn’t use conventional color coding. Most installers use the color coding as noted but be aware that some do not use the thermostat color coding.

Y2 – This is the thermostat terminal for cooling second stage if your system is so equipped. Many systems only have a single compressor but if you have two compressors which should only operate off of one thermostat then you need the Y2 thermostat terminal for second stage cooling.


*The most common color I’ve seen used for this terminal and wire designation is light blue but this varies and is completely up to the installer what color to use. Most installers use the color coding as noted but be aware that some do not use the thermostat color coding.

W – This is the thermostat terminal for heating. This wire should go directly to the heating source whether it be a gas or oil furnace, electric furnace, or boiler,


White for W Terminal. *Although be aware that this may have changed especially if the person who wired the thermostat didn’t use conventional color coding. Most installers use the color coding as noted but be aware that some do not use the thermostat color coding.

Answer 2

Bryant Thermostat Wiring