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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22245
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I am wiring a replacement ac air handler transformer but colors

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I am wiring a replacement ac air handler transformer but colors seem backwards from original install. My original transformer had two prongs on one side labeled "LOAD" attached to a red and brown wire. The other side has 3 prongs and has a "230" to a black wire, "208" empty and "C" to a pair of yellow wires. My replacement has wires no prongs (totaline P201-3401). On the sticker it says


it seems like the blu/yel are opposite between the transformers where original seems to have been my HI V side with 3 prongs as two are labeled 230/208. My new one clearly labels blu/yel as secondary 24V. So which go to which when I install?



tie the 2 yellow wires to the transformer white

tie black wire to transformer orange

cap the transformer red and black wires separately and do not use.



24 - load


tie the red furnace wire to the blue transformer wire

tie the brown furnace wire to the yellow transformer wire.

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