Wiring from a 20-yr-old thermostat


Old 09-20-20, 11:09 PM
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Wiring from a 20-yr-old thermostat

I am in need of replacing few 20-yr-old thermostats at home. Unfortunately those wiring, albeit being the right number matching many available ones on the market, I am not able to identify the functions of the wiring and match them to the coding on the present ones (Y, G, C, W, R, O/B.....) It would be great if some of you out there can make some sense out of the photos I attached here and provide some advise. Many thanks!

Old 09-21-20, 09:56 AM
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Welcome to the forums from Asia.

You need to put non-US in your user bio.

I don't recognize that thermostat but it looks to be a high voltage model. That would indicate it connects to a P-tac (self contained) system and wouldn't be compatible with a standard 24v thermostat.

Is there a model number on that thermostat ?

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