How to wire WiFi thermostat to oil furnace?

Old 03-03-23, 12:39 PM
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How to wire WiFi thermostat to oil furnace?

Hi, I purchased a Honeywell RTH6580WF smart thermostat (see photo) only for heating control as a replacement, but our oil furnace is a Honeywell R8184G4009 (see photo). The oil furnace control has only 2 wires (see photo) going up to the old thermostat, but my new WiFi thermostat has several wire slots (see photo of the plate). Can anyone please help me figure out which wire slots on the plate of the new thermostat should the white and red wires from the furnace connects to? Also, where should my new 24v power supply connect to the slots? Interestingly, the G wire label on the plate is situated in between 2 slots - not sure what does this means. No wiring diagram please, sorry I'm not technically inclined to read.
Thank you and I hope you all have a great day!

Honeywell Home RTH6580WF.

Oil furnace control. 2 wires only white and red labeled TT going up to the thermostat.

Back of the WiFi thermostat. Notice that the G is in between the 2 slots. R and Rc has a jumper wire.
Old 03-04-23, 03:30 PM
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Welcome to the forums.

Sorry for the delay in responding.

The TT connections are for burner activation but the thermostat rarely connects to that point with an oil furnace. Does your furnace have a fan center with a relay and transformer module ?

If not then you may an older furnace that doesn't use a fan center to operate the blower
but uses a fan/limit switch to control the blower.

If you are certain your two thermostat wires do connect directly to the TT terminals....
then there is no C connection available there.

You also need three wires to take advantage of a C wire..... had one been available.
Old 03-14-23, 03:13 PM
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Assuming you are still working on this, it might be helpful if you post a pic of the wiring to your existing thermostat. Check your product documentation, your new thermostat might not require a C wire, although a C wire would be best.

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