# Honeywell WiFi THermostat - S1 / S2 wires??



## steve-19 (Oct 26, 2010)

I have a heat pump and a furnace. I have R, Y, W, G, C and O wires... I also have S1 and S2 wires (sensor wires I assume?)

The new thermostat does not specify if/where I plug in the S1 and S2 wires. 

I plugged O into O/W and W into Aux/W2










Here's the old thermostat wiring ^^



















Here's the new wiring ^ ... S1 and S2 are not hooked up. Should I just cap them?


----------



## gregzoll (Dec 25, 2006)

Yeah, just cap them. Which Honeywell thermostat do you have? What make & model was your old thermostat?


----------



## beenthere (Oct 11, 2008)

Is the new thermostat dual fuel rated? Does it have a wireless outdoor temp sensor? If not, it will bring on both your heat pump and furnace when it gets colder outside. Which can harm your heat pump.


----------



## steve-19 (Oct 26, 2010)

I tucked them into the wall..

RTH9580WF is the new thermostat.

The old one was Carrier tstatccphp01

I ended up tucking them into the wall.

The new thermostat downloads the current temperature and humidity from the internet. I am not sure if it is dual fuel rated. 

I do have another question that popped up after I installed it. 

I have a heat pump and an electric furnace. I moved in two years ago and the heat pump never functioned with the old thermostat, I've used it for central air only. 

When I turned my heat on with the old thermostat, only the furnace ran.

When I setup the new WiFi thermostat, i had to select Forced Air or Heat Pump. I set it up with Forced Air and then it asked it it was one stage or two stage... It said to select one stage if only one "W" wire was used, but I used two (counting the heat pump wire), so I selected two stage. The heat pump still doesn't power on utilizing this method. I then set it up as a heat pump and all it did was just kick the furnace on, the heat pump did not run. I am thinking that it is not even hooked up. I think I should call an HVAC guy out to let me know how everything is setup... but any comments or suggestions would be appreciated until I do.


----------



## hvactech126 (Nov 11, 2010)

Electric furnace: please tell us the model number of the outdoor unit and brand. Have you verified the thermostat wiring at the furnace (AHU = air handling unit) and at the HP? That is the first place that I would start. Check to see if some idiot installer put a outdoor thermostat in the HP that prevents it from coming on below a certain outdoor temp.


----------



## steve-19 (Oct 26, 2010)

hvactech126 said:


> Electric furnace: please tell us the model number of the outdoor unit and brand. Have you verified the thermostat wiring at the furnace (AHU = air handling unit) and at the HP? That is the first place that I would start. Check to see if some idiot installer put a outdoor thermostat in the HP that prevents it from coming on below a certain outdoor temp.




I attached a few pictures of my heat pump and furnace. I took the small panel at the top of the furnace off, but there seemed to be some insulation with sticky stuff on it, so I didn't mess with it. Should I take the top or bottom panel off to get to the electrical.

The outdoor unit is a carrier, the model # is on the first pic.


----------



## hvactech126 (Nov 11, 2010)

Top panel is electrical (kill power to the ahu before opening). Also check the low voltage connections in the HP


----------

