Replacing Doorbell Transformer

Question

I currently bought a Ring Doorbell and am trying to locate my transformer that powers it since it is unable to activate my indoor chimes. I'm in a condo and do not have access to the attic but do to the crawlspace.

I have a forced air electric furnace by the front door that is closest to the power panel but I cannot locate a transformer in or around it. About midway through my living room, under the stairs, is where my water heater is located. There, I found a transformer attached to where the water heater's power is connected. This is about 20 or 30 feet from the front door.

I turned the water heater off and the electricity test tool would still beep by the low voltage wires out of the transformer. I then turned the breaker off for the doorbell and it stopped beeping.

My questions are:

Is this uncommon for a transformer to be located so far from the doorbell and thermostat?

Can a doorbell and thermostat share a transformer?

I'm not convinced there isn't a hidden transformer maybe in a wall but both my thermostat and doorbell only have a small hole allowing the wires to come out. My next steps might be to cut the drywall out a bit behind the doorbell, but any suggestions would be greatly appreciated!

Answer 1

The simple answer to your questions. Is it uncommon for the transformer to be mounted so far away from the door bell and thermostat. The location is not specified in code and many contractors locate them at or above the chime unit or in an water heater / furnace closet. So it is not unusual.

Can a door bell and thermostat share a transformer? Years ago it was not something I have seen pre 1980’s, As we get into the y2k era I have seen furnaces and door bells sharing transformers more often and there is nothing in code stopping this.

I would do what @jsotola suggested and pull one side of the transformer red or white it won’t matter see if the doorbell still works if not and it will after reconnecting you can be 100% sure that is the correct transformer.

Get a larger transformer same voltage but more VA to run the ring I thought I have read 30va was enough so if you have a 20 get a 50 or with 2 doorbells converted to ring 80 or 100va as long as the voltage is correct it will not hurt to go bigger or as big as you may foresee using.

Answer 2

Thats definitely a transformer, but probably not for you door bell. The wires from a transformer to the door bell button are commonly 18-22 gauge solid core wires. There's a red and a white wire in a brown protective sheathing. The transformer will be installed like the one in your photo and will be labeled that is stepped down from 115V AC to 15-34V AC.

The bell transformer is commonly installed close to the door, but also where ever a discrete power source is available (ie closets, cupboards and such).

Look for your chime device it may be built into the door chime enclosure.

Turn the breaker off for the transformer in photo #3. Check for AC voltage. If there's no power disconnect the (2) wires shown in the photo. Cap or tape each wire. Switch breaker back on. Ring the door bell. "Ding-Dong?" Not the transformer for the bell. "No sound?" That's the one.

Answer 3

There are some intercom systems that have one transformer serving multiple doorbells with a common central unit. The transformer can be quite far away. These are common in condos.

Only solution I know is to get a an electrical tracer and attach it to the wires coming out of your doorbell.

See this question for more details: How do I find the master unit for an intercom?

Answer 4

The picture clearly states it’s a Nutone 515-N transformer (read the letters on the transformer). So - yes, it’s the doorbell transformer. This is an old post, but I think encouraging people to read what’s written on an electrical device is a key step that was overlooked.