I'm trying to debug why one of my doorbells isn't working, but to keep things simple, today I'm just trying to understand the reasoning and implications of what I see at the electrical box.
Background: The house has two doorbells; one original location (1967) and one added with an expansion (1980s?). When I moved into the house in 2019 I installed a Ring Doorbell Pro at the Expansion door; it worked; I was happy. The other doorbell does not work, although there is electricity in the wires at the doorbell (wires spark / read 12-20V with a multimeter).
Looking at the electrical box I see two transformers attached to the side. They appear to be wired in parallel? The silver transformer is marked 16V and the other isn't clear. There is only one wire pair (red/white) leaving the transformers and going off into the house. (Click for larger version)
So my questions are as follows:
- What is the effect of this wiring setup? Higher current?
- Why would two doorbell transformers be wired together like this? Cheaper than buying a bigger one when the expansion was added?