Portland · Since 1979

What Those Weird Noises From Your Furnace Mean

Usually, your furnace makes a nice, comforting hum when it works. However, it’s been making some weird noises lately. Here’s what they might mean.

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Posted in Prevention & Preparation

Your furnace has started to make weird noises, and you don’t know what they mean. You may wonder if it’s nothing to worry about or something that needs attention right away. Here are some noises your furnace can make and what they might mean.

Clunks, Rumbles and Rattles

When you hear these kinds of noises, it usually means that something has come loose inside your furnace. It can also mean that the heat exchanger has cracked. The first problem is an easy fix for your HVAC professional. If the second problem is causing the racket, you need a new furnace.

Clicking Sounds

There might be a brief clicking sound when the furnace first comes on, but it shouldn’t continue. If it does, it indicates a faulty thermocouple, a faulty gas valve or dirty burners. There could also be something wrong with the ignition control board.

Buzzing Noises

You may hear a split-second buzz when your furnace ramps up its blower motor. If the buzzing lasts longer than this, you should have your HVAC professional take a look at your furnace. It might mean that there’s something wrong with the furnace’s electrical system. This is something that an electrician should address as soon as possible.

Knocking Sounds

Sometimes a brief knocking sound is harmless. It can mean that the furnace is warming up or cooling down. On the other hand, knocking can mean that something’s amiss. Things that cause knocking include debris inside the furnace, a filthy air filter or something in the furnace that’s come loose. Knocking can also be caused by inadequate insulation or a problem with the ductwork that connects to your furnace.

Whistling

When you hear your furnace whistling, the culprit is most likely a dirty air filter. The dirt and dust that’s accumulated in the filter is choking off the appliance’s airflow. This is why it’s important to clean or change air filters regularly. Another reason for whistling is a leak in the air duct. A simple-to-fix problem that causes whistling is a vent that doesn’t close all the way.

Squealing and Grinding

These sounds indicate a problem with one of your furnace’s motors. It develops when the bearings have worn out, and metal components start to grind against each other.

Call Us if Your Furnace Is Making Strange Noises

Strange noises from your furnace need to be evaluated, for they may be the result of an easily fixable problem or something very serious. For furnace repair or furnace replacement, call on our HVAC professionals at Sky Heating, AC, Plumbing & Electrical in Tualatin, OR.

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