Furnaces are meant to be quiet. Aside from a background hum, once they’ve been switched on, you should hardly hear anything at all. Unfortunately, over time, furnaces may become noisy. A furnace making a clicking noise is particularly problematic because it indicates the unit has a serious problem. While only an HVAC technician can diagnose the issue, here are the most likely causes.
Loud Circuit Board
In a furnace, the circuit control board is the relay station, passing messages from one component to another. Switches flip on and off throughout the heating cycle to keep warm air flowing through your home. In most units, these switches flip on and off quietly, but in some, they’re clearly audible. Replacing the circuit board will solve the problem, though it may not be worth the expense if the rest of the unit is running smoothly.
Worn Out Bearings
Ball bearings reduce rotational friction in furnace fans. However, absorbing this pressure can wear them down over time. When this happens, the fan assembly will start to click as it slowly becomes unstable. Furnaces can operate with worn bearings for a while, but if they aren’t replaced, the fan will eventually fail.
Dirty or Damaged Fan
Furnaces contain two fans: a blower and an inducer. The first sends warm air into your home. The second sends smoke up your chimney. If dust builds up on either one, it can throw them off kilter. Chipped or broken fan blades do the same thing, resulting in a clicking noise as they spin.
If you own a gas stove, you know it clicks before igniting the burners. The same thing happens in your furnace. The igniter clicks as it sparks. However, if the igniter isn’t working properly, it may continue sparking even after it’s lit the burners, either because its electrical components have worn out or it has a bad connection with the flame detector.
Bad Flame Detector
The flame detector, also known as the thermocouple, shuts off the igniter after the burners have been lit. However, if it’s dirty or malfunctioning it may not register the flames or signal the igniter. Unless it’s cleaned or replaced, the igniter will keep sparking until it wears out.
Broken Gas Valve
Gas valves are a crucial choke point in your furnace. Without fuel, the burners won’t ignite to supply heat. Worse, if they don’t ignite, the flame detector won’t shut off the igniter, causing it to spark endlessly until the whole unit is powered down.
Faulty Pilot Light
Older furnaces use a pilot light instead of an ignition switch. As gas flows into the unit, it hits the light and ignites the burners. But when the pilot is dirty or the mix of gas and air isn’t right, it won’t produce a strong enough flame. As a result, the furnace will automatically shut off and restart, a safety precaution designed to prevent gas leaks. This constant cycling creates a lot of noise and requires immediate attention from an HVAC technician.
Circulating air doesn’t exert much pressure on your ventilation system, but if your ducts aren’t tightly secured, it can cause a problem. Loose ducts rattle and click. A noisy furnace is troublesome, but the sound tends to be localized. Noisy ducts, on the other hand, can be heard all over the house.
Protecting Your Heating System
A furnace making a clicking noise won’t be covered by home insurance. Damaged fans, faulty igniters, and worn-out bearings are the result of wear and tear, not an accident or disaster. In these cases, it’s the homeowner who’s responsible for the bill, not their insurance company.
Repairing a furnace can cost hundreds, if not thousands of dollars, so make sure you’re protected with a HomesentialTM warranty. We’re here for you when your heating system wears out. Our service team schedules the technician and pays for the repair or replacement of all covered parts. There are no deductibles or service fees. Just a low monthly premium ‒ less than what you pay each day for a cup of coffee. Bundle your coverage for even greater savings. Sign up today!