Will the thermostat work with an older Williams furnace?

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1

Hello. I have an older Williams furnace in my new place. Can I use my Wyze thermostat with it? The model # is 465FX-R NAT.

Thanks in advance.

2

What does the wiring look like at the thermostat location?

Bat signal for resident pro: @speadie

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3

Yes, however as this is a millivolt furnace, you will need a C transformer and an Normally open isolation relay.

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4

I’ll have to pull the cover off and have a look. Can I post photos here?

5

Oh my…This might be above my head.

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it’s not too difficult. I’ve linked the items you would need. For the isolation transformer, pin 1 would need to be connected to W1 on the wyze and pin 3 to C on the wyze. Pin 4 would be connected to W1 on the furnace and pin 2 would be connected to C on the furnace. The wires from the C transformer would be connected to Rc and C on the thermostat, no need to worry about which ones go where.

Isolation transformer might not be necessary, but some people have reported erratic behavior on milivolt systems without one.

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