Q&A / 

Doorbells & Door Chimes

Kathy, my wife, just doesn't like doorbells, door chimes and especially the buttons. As a result, we have beautiful solid brass door knockers on our front and side entrances. When those bad boys are "activated," they can be heard down the street!

Last week, we missed a UPS delivery because we don't have a doorbell or button adjacent to the door that leads from the house into the garage. I had coated the front and side porches with a wood sealant and the UPS driver had no other choice but to use the garage entrance. He is not the only person to use this back entry. Often people mistake our garage door opener buttons for door chimes. To make a long story short, I'm installing a lighted button at the garage door that will operate an old fashioned doorbell. The Carter house is climbing out of the dark ages!

Simple Devices

Door chimes are very simple electrical devices. They operate on low voltage (commonly 16 volts) and the electrical current is direct current (DC). Regular household high voltage wiring is alternating current (AC).

Direct current devices obtain their power from transformers that push electrons out from one terminal screw and pull them back into the transformer at the other terminal screw. In other words, a DC transformer is nothing more than a small electrical pump - it pumps out electrons instead of water. When you install a simple switch and a doorbell between the two terminals, you create a loop. The electricity flows out of the transformer past the switch, into the bell and then back to the transformer. As the electrons pass through the bell, they "tickle" it and make it vibrate or ring. More sophisticated door chimes do the traditional "Ding - Dong" or play a four or eight note tune.

The Loop

To solve pesky door chime wiring problems, you need to always keep in mind the loop wiring diagram in your head. If you understand how the electrons are supposed to flow, you can almost always quickly identify where a problem exists in your doorbell/door chime wiring loop.

If you don't own a simple volt meter, I suggest you go to Radio Shack and buy a medium priced digital or old fashioned VU meter volt meter. This is absolutely necessary if you want to locate a doorbell problem.

Check Connections

If your current doorbell/door chime doesn't work, the problem will very likely be a loose connection, a broken doorbell/chime, or a burned up transformer. I always like to check the transformer first to see if it is generating power. This is where you need the voltmeter. If you touch the two leads of the voltmeter to the two screws on the transformer, you should see the voltmeter register power. If it doesn't the transformer is bad and/or the high voltage power feeding the transformer is off. If you have 16 volts or near that let's move on.

The door buttons are the second place to look for trouble. I always remove the cover and detach the wires from the button. If you touch the two ends of the bare doorbell wires together it very possibly will activate the doorbell/door chime. If you see a brief spark and no noise from the chime, it usually means that there is a problem at the bell/chime. Don't continue to touch the wires together as you can burn up the transformer!

To test to see if the door chime is the problem, I suggest you purchase the least expensive doorbell or buzzer. Go to the current door chime location and hook up the buzzer or bell to the existing wiring. If you hook up the wire from your existing chime that is attached to the screw that says "Trans" and then you attach the other wire to the buzzer that is connected to the screw that says "Front", you should hear a BUZZZZ when you push the front door button. This assumes that you have power at the transformer and the button works.

Old Wiring

If you have an old house - say 50 years or older - there is a possibility that the low voltage doorbell wire has older cloth insulation. This insulation can deteriorate and cause shorts to develop. If you check out the transformer, button, and bell/chime and all seem to work, you could have bad wire.


The transformer for your door chime system should be adjacent to your electric panel. In fact, they are allowed to be connect directly to the side of the panel through a regular 1/2 inch knockout.

Transformers are affected by heat. Never install them in an attic or other area where they will be subjected to high temperatures. If you are installing a new chime, ALWAYS install a new properly sized transformer. They are inexpensive!

Column B209


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