24V 40VA Control Transformer， Primary 120, 208, 240V Secondary 24V Isolation Transformers，24V Transformer with Foot Mount for HVAC Furnace Multi Tap

This died in our Weil Mclain steam boiler after 20+ years. Perfect replacement, no problems. I'm an EE so replacing a transformer was a pretty simple operation.

Works great. I prefer the transformers with studs directly on them, but these work no problem and was fast to get.

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.

Good functioning product, bought this transformer for a project I was working on. I did not expect a high quality long lasting transformer but this item exceeded my expectations.