Fan Only Thermostat Wiring

Most people dont use the fan only mode so while youd give up control over the fan in the system youd gain constant power to the smart thermostat.

Greentech bladeless oscillating fan qr9. Fan works only if thermostat set to fan on. This qa were posted originally at fan on auto man thermostat switch faqs. I have an older furnace with only 2 wires at the thermostat white and red.

These thermostats will have 3 terminals usually marked r w and g. This additional terminal is labeled g in the thermostat. I only want this option to help circulate air in my house.

No issues at all with my system works as should. I do not have central air so the cool mode is useless. Everything on or everything off.

This wire may be red without an h attached in some cases. Wiring the fan only option is not difficult as long as the. But thermostats can also be used for home air circulation and filtration with the fan only setting helping to save on your energy bills.

I want to be able to turn it on fan mode only. You may read our guide on 2 wire thermostats which also covers 2 wire single pole thermostats for line voltage systems. While its important to know these industry standards your wiring may be different.

Again referring to the honeywell thermostat ct31a1003 wiring diagram you can see it requires only two wires r and w. The rh wire connects to the heating system. Configure the thermostat following the manufacturers settings.

It doesnt control cooling and because its a mechanical thermostat it doesnt need power for internal functions so it has no c wire. After reading about it online i wanted to try running the furnace in fan only mode to see if it would recirculate some of the air from my 2 window ac units. Connect the thermostat to the baseplate.

The blue wire on the thermostat is the common or c wire. Thermostat is new honeywell basic model not smart. Where g terminal is to connect fan of the furnace.

Thermostats provide a variety of options to control the temperature and comfort level of your home. Why the blower fan runs only in the man on switch but wont run on auto. This is very common in older systems in order to get separate fan control you would need at least three wires but at the other end of the cable the furnace would also need to be wired for this option.

Fan wont work when thermostat set to fan auto. Use this guide as a reference only. I do not have an ac unit attached.

Youll also have to change the wire at the furnace from g to c. So my thermostat has two switches system with cooloffheat and fan with onauto. Heat only thermostats are also known as 2 wire thermostats.