CT101 doesn't turn on blower with heat, only cool

Other Devices & Integrations Climate Control & Temperature Sensors
#1

Hi all. Have had a radio thermostat CT101 installed since earlier this year. It’s sync’d to my vera, and I can control it and monitor it just fine.

However, freezing temps are starting today in the Northeast and I’m afraid I don’t have a photo of how the wiring looked prior to swapping it out this past summer; only what it looks like now. I’d imagine that I would have placed the wires exactly where they were before on the dumb thermostat. Also, I don’t have a common wire, so the blue line that you see isn’t a common.

The blower at the air handler turned on when I had the air conditioner on this year. However, this is my first time attempting heating as it will be below freezing tonight, and the blower won’t turn on when I turn on the heat. I can force the fan on so that the blower runs and it works fine, but it just won’t work on auto. I’ve included a photo below.

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Any ideas? I’ve since joined RC and RH with a jumper wire thinking that was it, but to no avail. Would like to get this working as i’d rather avoid having to keep the fan on 24/7 and instead, only run automatically. The Vera app also doesn’t allow you to force the fan setting, so it defaults the purpose of installing a smart thermostat since I have to manually walk to the thermostat to turn on the heat.

Thank you so very much for any advice anyone may have.

#2

What kind of system do you have? Is this a heat pump without aux heat?

#3

Thanks Tinman. It’s a forced hot air system, gas furnace with disparate zones via hot water circulators in the basement. The one above is for my upstairs attic space, which has its own air handler and blower. The ductwork is utilized for both heating and cooling. The taco pump in the basement forces water up to the attic air handler through a heating coil which circulates hot water. The blower could then blow across the coils of hot water, thereby introducing hot air into the rooms.

The problem here is that the blower doesn’t turn on unless I force the fan setting to on, it won’t run on ‘auto’.

#4

So when heat is needed the thermostat is turning on the gas furnace and the pump which circulates the hot water but the fan isn’t being turned on? If that’s the case then it’s probably not a wiring problem. It may be something to do with how the thermostat is configured. You cold try changing the HVAC setup in the thermostat. Your best bet is to try to get some support from radiothermostat.com. I would think that if you describe your system and the problem you have, they could suggest the correct setup.

#5

Agreed. You may have it configured for the wrong type of heating system. It sounds like it is in “boiler” mode (radiators) and you need forced air controls.

Alternately, you may need to splice the pump and blower controls into the same control wire.