My old thermostat, Honeywell Pro 1000/2000 used 5 wires; 1 for power from the thermostat, 1 from fan relay, 1 from A/C relay, 1 from furnace relay, and common from other side of each relay. The White-rodgers F178 unit I purchased only appears to use 4 wires so I'm a litttle confused what to do with the common wire from the other side of each relay.

The Honeywell RTH2300 doesn't need a C-wire. See the documentation in the Installation & Setup section on the support page: https://www.honeywellhome.com/us/en/support/air/thermostats/programmable-thermostats/5-2-day-programmable-thermostat-w-change-reminder-rth2300b1038-e1/ . If your old thermostat had a C-wire, check the system board at the furnace. Make sure that the G-wire (usually green) at the thermostat is also connected to the system board's G-wire connection.

First check the obvious: what is the current position of the fan switch? It should be on auto. (That's the switch on the right.)

Is the temperature that the thermostat is reading match the real temperature in the room? Check with a thermometer. If the area near the thermostat is still above (cooling) or below (heating) the set temperature, the room circulation could be a factor. I know my home's thermostat keeps the A/C running for a while after a thermometer on the other side of the living room reaches the desired temperature in the evening when parts of the house are closed off.

If the thermostat temperature reading is correct, the signal may not be reaching the system board. You can check that all of the individual wires between the thermostat and the system control board are undamaged. I've seen those thin wires break when you take them off one thermostat and connect them to another.

Another possibility is that a relay isn't working. Contact Honeywell if the temperature sensor isn't giving the correct reading. Contact a heating and cooling repair person if the problem is with a relay or the system board.

I hope this helps.

Cindy Wells

R= power G= fan Y= cooling W= heat

In order to hook this up to the fan on your furnace, you will need to either have or install a Fan center @ the furnace. (Unless it is gas, and has a circuit board that will simplify the process) All this is, is a transformer, a relay, and a set (or two) of NO and NC contacts. You will need to run 3 wires from the thermostat back to the furnace, if you do not have them already. If you have a gas furnace with a circuit board then all you have to do is connect the three wires from the thermostat to the board. (R to R; W to W; G to G. If you are using an older furnace, or a oil fired appliance, power should go out of the transformer (secondary side) to the thermostat on R. It should then come off W and another wire off G back to the furnace. Connect to the appriately marked terminals on the fan center. Hope this helps

This is a Focus Pro 2 heat,2 cool thermostat. If you are connecting this to a single stage(1 heat) residential furnace then your connections are: At the thermostat the R and Rc therminals are internally connected so you can connect your R terminal wire from the furnace to the R terminal at the thermostat(this is your 24 volt supply for both heating and cooling. The W or W1 wire (heating) from your furnace you connect to the W1 terminal at the thermostat. The W2 wire from your furnace(if your furnace is a 2 stage furnace) you connect to the W2 terminal at the thermostat. The G wire from your furnace(indoor fan) you connect to the G terminal at the thermostat. The Y1 wire(cooling) from your furnace you connect to the Y1 terminal at the thermostat. The C wire(common or neutral) from the furnace you connect to the C terminal at the thermostat.

usually you should have 4 or 5 wires....if you have AC then this wire should be Y if not was it connected at all before?...Heating requires only R&W

need to make sure there is a jumper between RC and RH if the red wire is connected to the RC terminal the heat wont work you will need a jumper wire to tie the RC and RC together with the red wire.

Check to see if you have power at the furnace. You thermostat is powered by 24vac coming from the furnace. You should have power on the "R" terminal.

with the fan in the auto position, the fan only comes on during a demand for heat.  does it not come on during a demand for heat?