I am in the market for a Ring doorbell and was googling on how to find a doorbell transformer. I believe I have found it, but it’s attached to the furnace switch.

The wires connected to the transformer are skinny and sticking out from the wall (a sign that this could be the doorbell transformer). But to be on the safe side I did the following tests: Remove one wire from the transformer and test the existing doorbell and the furnace - when I turned ON the furnace switch the furnace light still turns on but when I pressed the doorbell button the doorbell stayed silent. I put the wire back onto the transformer, and the doorbell was ringing again.

The transformer shows 5va-10v, so this is way underpowered. How do I replace this transformer with this setup? Or would the Ring bypass option work?

Doorbell(?) transformer attached to furnace switch

current transformer setup

  • 1
    How do I replace this transformer? Well, you take the old one off and put on the new one. The general design of the transformers hasn't changed so it should be a direct replacement. Did you have a more specific question on the replacement?
    – JPhi1618
    Commented Jul 15, 2019 at 14:15
  • I added a second picture to show the setup - where transformer sits on top of the furnace switch. I suppose just remove the screws on the switch and I should be able to remove the transforme
    – punsoca
    Commented Jul 15, 2019 at 14:22

1 Answer 1


Once you remove the cover of that box with the switch and everything else, you should see three wires coming into the top of the box from the transformer. These are usually white (neutral), black (hot), and green (ground). Take a picture of all the wire connections and make sure that everything gets connected the same when you wire in the new transformer. There will be additional wires in this box that are connected, and these connections all need to remain the same.

The transformer will most likely be physically attached to the top of the box with a conduit nut (inset of picture).

Doorbell transformer

These can be hard to remove and install in a small box, but the basic method is to place a flat headed screw driver on one of the raised portions of the nut and tap it with a mallet to spin the nut in the correct direction. The new transformer needs to be tight. Loose connections lead to loose or damaged wires, and that leads to bigger issues.

When you reattach the low voltage wires to the transformer (the red and white in your pictures), it doesn't matter which screws the wires go to because it is alternating current (there is not a positive side and negative side like with a DC power adapter).

Any "modern" doorbell transformer will be 16VAC, which is what the Ring wants. You are correct that this 10VAC transformer is not powerful enough, regardless of how you wire the Ring. Note that if you plan on using your current chime, a higher voltage transformer might not work. It could damage the chime (immediately, or in the long run). Plan on replacing or removing the chime as well.

  • Thank you! I’m not really a handy guy but this illustration definitely help. But speaking of the door chime - I read that the Ring chime (sold separately) can be used with Ring Pro - is there a way to bypass the mechanical door chime and use the Ring chime instead?
    – punsoca
    Commented Jul 15, 2019 at 15:05

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