WUYELIN 24V 40VA Control Transformer, Primary 120/208/240V, Secondary 24V, Isolation Transformer, Foot Mount for HVAC Furnace, Multi Tap, CE Certified, 1.66A, 50/60Hz

Well documented and fully functional.

Works as described

Pretty good quality, easy installation and good price

UPDATE 6/5/25: I noticed that the seller has used these diagrams to provide input wiring instructions in their product photos. I will assume that they have updated their paper instructions as well. Therefore I am upgrading this to a 5 star product. -------------------------- Several reviewers have posted about these transformers blowing up / catching fire / burning out after a short period of use. Since the wiring instructions that came with the product were equally as helpful as the product photos, I am sharing what I have learned after instantly blowing up this transformer and having it catch fire. Initially I wired this transformer as follows: White-Neutral, Black-120v, Orange-120v. I immediately discovered that I was wrong. I was able to communicate with the seller using diagrams and they said that this transformer is designed to only use a Neutral on White and a single Hot on either Black or Red or Orange, depending on the voltage of the Hot wire. See photos noted "according to seller" TBH I don't think the seller is entirely correct because although 220V Hot legs are standard for residential power in Europe and China, I am unaware of any single-Hot 208V power system anywhere in the world. You get 208V from two 120V Hot legs that are 120 degrees out of phase from each other. Theoretically you should be able to power this transformer at 240V or 208V in the USA without a Neutral by using two out-of-phase Hot wires, with one of the Hots going to the White wire on the transformer (see photos noted "UNTESTED"). However, your best option is to just wire the transformer for 120V whenever possible. As for the product, minus 2 stars for poor wiring instructions and plus one star for excellent customer service. The build quality looks and feels good. If they update their product photos and paper instructions with clear and simple wiring diagrams for supplying each voltage in the USA then I will give it 5 stars. Regardless, I would definitely buy from this seller again.

No problem with this transformer. Replaced the one in my heat pump air handler. The original had been humming for years and finally died. The wire colors are different from standard as is the case with most china transformers. The voltage info needed to hook it up is clearly printed on the label. The printed paper diagram was generic and useless for my purposes . Item shipped fairly quick so no problems there.