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Emergency Service

Hailey and Boise


Twin Falls



4 Heating System Noises You Shouldn’t Ignore

ignore-noise-cover-earsIt takes a few minutes for the fan of a furnace to finally start that familiar whir sound. That’s because it takes a few minutes for the furnace plenum to actually heat up after the burners light, and the fan does not start running until it is warm enough to deliver air to the vents in your home. Once you do hear that spinning, whirring blade and the rush of air through the vents, it’s a satisfying sound—unless it’s accompanied by an unfamiliar noise.

Other than the sounds you are familiar with as your furnace starts up, you should not expect to hear much else as the system runs. If you notice noises from the vents or the unit itself, it’s usually time to call in technicians. Here are 4 of them you cannot afford to ignore.

1. Loud Bang at Startup

We’re going to start with the noise that likely scares you the most, when you hear a loud banging noise coming from the furnace. If this happens consistently, rather than when the furnace first starts up, it could have to do with the air ducts or the sheet metal siding of the furnace expanding and contracting, the result of poor duct installation or improper furnace sizing.

If this happens only at furnace startup, though, you have reason for concern. This may be due to something as simple as a dirty furnace burner. However, that dirt allows gas to buildup, causing a sort of mini explosion when the burners finally do ignite! While it may not affect your home right now, this rattles the heat exchanger, which could eventually crack and leak poisonous carbon monoxide into a home.

2. Squealing

That squealing you hear from the furnace may be the result of a lack of lubrication or a blower fan belt that is wearing out. This means it’s an easy fix for most technicians, so why is it such a big deal? Because, if you let it go on for too long, the fan may stop working, stopping the furnace from running when you need it most! It’s better to repair the problem now than to wait for a system breakdown.

3. Low Rumble

If you hear a low rumbling noise, it’s probably loudest when you are right near the unit. It’s hard to say what the cause is without seeing and hearing the furnace ourselves. One common explanation, though, is that the pilot flame is too low. Check the flame to be sure it is blue rather than yellow or orange. Otherwise, a rumbling noise could be attributed to a dangerous carbon monoxide leak, depending on the unit, so shut off the system and call for help if you believe this may be the case.

4. Scraping

Finally, we don’t think a scraping sound—like metal on metal—should ever be ignored within a furnace. Most likely, the motor mount has come loose from its casing. In other words, it’s just what it sounds like: metal scraping on metal.

This might not seem like such a big deal right now. However, the damage that can result to the blower fan may be severe enough to require replacement, whereas it may only need quick repairs if scheduled right now!

Don’t delay! Get service for your heating in Kimberly, ID from the expert technicians at Evans Plumbing Inc.

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