If your doorbell is relentlessly buzzing or humming, the button may be stuck in the contact position. If this continues for very long, the electromagnet will burn out and the bell unit won’t work even if current is being delivered to it through the button.
You will need to immediately disconnect the button from the wires and repair or replace the button. Otherwise the bell unit will wear out and you will have to replace it. For instructions on disassembling a doorbell button, see below. To understand the components inside a doorbell, please see the diagram at How Doorbells Work.
If the bell doesn’t ring, but the transformer hums when the button is pushed:
1Check the bell. Be sure the wires are connected to the terminals in the bell unit. If necessary, clean the contacts with fine sandpaper or electrical contact cleaner.
2Check the piston. It may be worn and jammed inside its sleeve or gummed up if someone has tried to oil it in the past (something you should not do). If this is the case, replace the electromagnetic/piston component or the entire bell unit.
3Check the wiring. Look for any breaks in the doorbell wiring. If you find one (or more), strip the insulation from the wire ends and splice them with a short piece of matching wire, using properly sized wire nuts.
If, when you push the doorbell button, you do not hear a bell, a hum, or even a click, it often means that electricity is not being delivered through the system.
1Check for a tripped circuit breaker.
2Check for a burned-out transformer. Turn off the power to the circuit before working on the transformer. See How to Check a Doorbell Transformer.
3Be sure all wires are connected securely at transformer, bell, and button.
4Remove and check the button. Because the button is the primary moving part of the system, this tends to be the most likely component to fail. To do this, remove the button’s attachment screws and gently pull the button out.
Be sure the two wires are connected securely to the screw terminals. Then touch a screwdriver blade across both terminals (or remove the two wires and touch them together).
If the bell sounds, you are in luck; this is a very easy, inexpensive repair. Remove the wires, and clean corrosion from the button’s contacts and wire ends with fine sandpaper or electrical contact cleaner.
5Reconnect the wires. If the button still does not work, just remove and replace the button (available at hardware stores).
This button test will work if the power circuit is functional. If the button is faulty AND there is an additional problem, it won’t. If the simple button test fails to ring the bell, you can make sure the button is faulty by doing a continuity test with an ohmmeter (set on ohms).
Hold one of the meter’s probes on each of the button’s contacts, and then push and release the button. The meter’s needle should bounce up when the button is pushed and drop flat when it is released. If it doesn’t, the button should be replaced.
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