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bobalou · 06-20-2022

I have a 3 wire Honeywell thermostat that connects to a equipment interface module which connects to the circuit board on my AC/Furnace. There is no humidifier or dehumidifier. Looks like I’ll have to run a new 7 wire to make this work. Any help with...

bobalou · 06-22-2022

Wires are still attached to the interface and functional thermostat. I live in Georgia where temps have been very hot and my attic is around 110 degrees. So I'm delaying this until fall when it's cooler, plus I don't want to have A/C problems with th...

bobalou · 06-21-2022

Hi Thaler, my HVAC is a Trane XV 80. No humidifier or dehumidifier. Wish nest would put out diagrams for install. It’s not like Honeywell 3 wire thermostats routed to an equipment interface module thermostats are the newbies on the block!

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Honeywell TH9421C1004 Thermostat wired to Honeywell THM5421C Equip Interface Module

Re: Honeywell TH9421C1004 Thermostat wired to Honeywell THM5421C Equip Interface Module

Re: Honeywell TH9421C1004 Thermostat wired to Honeywell THM5421C Equip Interface Module