Technical Advice - Door Chime Power and Connections

Door bells run on stepped down voltage. Somewhere in the doorbell wiring system is a transformer that takes 110v input and reduces it to something ranging from 8v to 24v. Simple two-note chimes typically run on voltage somewhere between 8 and 16 volts. Multi-note chimes generally run on 16 or 24 volts. Some chimes have the voltage requirement stamped or printed on the chassis.  For motorized multi-note the power requirement will appear on the motor spec plate.

For best results and safest operation match your transformer to that voltage.  By my trail and error tests I conclude you can vary the chime volume to some degree by using a transformer or greater or lesser power, but I recommend no more than +/- 8volts variation from the intended voltage. Chimes that have an integrated clock that taps power off the door bell circuit should be run only at the recommended voltage in the interest of clock accuracy.

Under no circumstances should a doorbell be “tested” with 110votls as the test will be short and smoky.

When problems arise, many seem to question the transformer first-- perhaps as a matter of wishful thinking. Other problems are probably more likely. The very most likely problem is something in the chime itself. Or a door bell button might be worn out. The house wiring for the system might be compromised. The connections to the chimes might be wrong. When in doubt, about wholesomeness of the house circuit, I recommend doing an offline test of the chime. This requires building a test station consisting of a transformer and door bell button, wired like a miniature version of the house circuit. It may seem like a lot of work, but could save hundreds in avoiding hiring an electrician to chase down phantom problems. If you can positively isolate the problem to the house circuit, you may want to replace the door bell buttons and maybe the transformer before hiring professional help.

Something that you absolutely must consider when installing or upgrading to a multi-note chime is that a 3-wire circuit is required. The standard two wire circuit that provides momentary power to a simple 2-note "ding-dong" chime will not work for the more complex motorized chimes.  The reason is plain: a multi-note chime needs power while the chime runs its sequence, so a constant hot wire is needed to provide that power. If you want to upgrade from a simple 2-note chime to a motorized 3, 4, 8, whatever-note chime, upgrading your house doorbell wiring will be required. And just to keep things as complicated as possible, if your house has a simple 2 -note chime, but is wired for front and back doors, you will see three wires coming out of the wall, but those three wires are not adequate to run a motorized chime because those wire provide just momentary power from the two doorbell buttons.

BTW, if someone before you (obviously not you because you would know better) installed a motorized chime on a simple 2-wire circuit, the symptom would be that the chime would run only while the doorbell button is pressed and held, providing momentary power. It would stop the moment the doorbell button is released. Simple, right?

Here is the text from 1949 NuTone Jefferson installation instructions:

If possible use present bell wiring. This eliminates the necessity of installing all new wires from the door pushbuttons to transformer and chime. However, if you do use your present wiring it will be necessary to connect one more wire from the transformer location to the chime location. Before installing this new wire, replace your present weak bell transformer with the 24 volt NuTone Transformer packed with this chime.

Attach this new wire to the same transformer terminal to which the door pushbuttons are connected (see wiring diagram). This new wire conducts the 24 volt current to the Telechron motor in the chime mechanism. This motor is set into operation each time the front door button is pressed and turns until the eight note chime sequence is completed.

One unusual feature that I have observed is that Edwards multi-note chimes can not tolerate lighted doorbell buttons. It seems that the trickle of power that flows through a lighted button is enough to keep the disrtibutor motor from shutting of, so it will run continuuosuly. The solution is easy - just don't use a lighted button with an Edwards multi-note chime.

I frequently get email from people who say they have a bad transformer, or maybe bad wiring, or a bad chime but just not sure where the problem is... and can I help them figure it out? It's almost impossible for me to diagnose a chime or house wiring by remote control. Here's my advice for anyone who wants to debug their own. Like any multi-variable system, whether its an algebraic equation or fixing your car, the variables need to be solved for one at a time. My own chime test station consists of a miniature of a house door bell circuit, with 110v into a transformer of correct voltage, door bell buttons and appropriate wires. With this set up I can see all the parts, I can identify each one for sure, and I know that all are wholesome. If you make a set up like this, you can at least isolate the problem to your chime, or outside your chime, plus you can determine the correct connection scheme by quick trial and error if necessary.