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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I installed a Carrier Cor WiFi Thermostat today and followed

Customer Question

I installed a Carrier Cor WiFi Thermostat today and followed the exact same wiring as the previous HoneywellThermostat that was connected to my Carrier Furnace and AC Units. I have a two zone system so I installed two of the COR thermostats. Set my cooling point to 74 for at night and my heat point to 68. The thermostat when into cooling mode when the house reached 75 after a while. It showed cooling on the thermo and the app but only heat was coming out and the house shot up to 84. Had to turn off the system and open windows to cool house. What did I do wrong?
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, is your system a heat pump with gas or electric furnace back up heat, or does the unit that sits outside run only in the summer when cooling is required.

I ask that because some thermostats have to be programmed for heat pump operation, and if not programmed, will heat when calling for cooling etc.

Tell me if that is what it seems to be doing or not, and if you want me to spend a few hours coaching you on all this or not.

We can go from there.

Customer: replied 1 year ago.
I have carrier two stage electric Furnace in the attic and two carrier AC units outside. My wires on the original thermostats was as follows: Rh jumped to RC with main red wire in RH, Y, C, W, G, W2. I photographed them and them connected it to the COR smart thermostat except instead of plugging the R wire into Rh I plugged it into Rc. The system detected all of the wires and it seemed like installation was all good.
Customer: replied 1 year ago.
My system is zoned for upstairs and downstairs too. with two thermostats. I have replace both honeywell with Carrier CORs
Expert:  Phil replied 1 year ago.

Thanks, ***** ***** a straight forward type of system and wiring set up, the problem is most likely related to the zone controls... so far however, the wiring errors if any are not obvious.

Is there a jumper between Rc and Rh... if so that is how it should be.

I need the full model number of the COR thermostats, just 'COR' is not enough. Meantime look at the programming instructions, you may have selected 'heat pump' as the system type instead of 'conventional system'

If I miss you tonight I will pick your response up in the morning.

Customer: replied 1 year ago.
COR model is TP-WEM01 and I was told that the unit is internally jumped so no need to put a jumper between Rc and Rh on the new COR Thermostat.
Expert:  Phil replied 1 year ago.

Thanks, ***** *****'t see any potential problems with the way you wired the thermostats.... can you give me the brand and model number of the zone controller these connect to? Or a photo of the thermostat connections to the zone controller.

Use the paper clip icon at the right end of the tool bar to attach the photo's please.

We can go from there.

Customer: replied 1 year ago.
I wired it according to conventional as I copied my old wiring. Here is the Old thermo wiring
Customer: replied 1 year ago.
Here is how I wired my new one:
Customer: replied 1 year ago.
Calling it a night for now. Can resume in the morning. Thanks.
Expert:  Phil replied 1 year ago.

Thanks, ***** *****'t see a problem with your thermostat wiring, there is must likely some conflict at the zone control box, get me those pictures I will look them over tomorrow please.

Locate the zone control box by finding the thermostat wire connections in the furnace and following that wire back to its source.

See you in the am or whenever you get back.

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