Furnace Noise 3

List of Noises 9:

High-pitched squeal
Squeaky sound
Growling/grinding sound
Humming noise

If you have a Keeprite N9MP1 single stage 90 AFUE furnace and the draft inducer has been making a high-pitched squeal then you may need to replace it:

The installation is very easy. If you have the technical ability to change your cars spark-plugs; you can do this too. Once the shipment arrived you'll find the following materials in the box:

1) motor and casing (since I bought the entire assembly)
2) 4 long threaded screws (to replace the current ones)
3) new power wire connector (to replace the current one)
4) rubber fitting with 2 clamps (which connects the inducer exhaust port to pipe of the flute)
5) o-ring style **adhesive** gasket (interfaces the draft housing to the back black plate)
6) instructional guide

Read the directions a few times before installing; then follow the instructions step by step. The only tool you need is a flat head screw driver - but no specialty tools are required.

Here is a couple items that came up during the install that the directions don't actually make mention of:

1) The gasket is a sticker-type. I guess this would be pretty obvious to some, but you do indeed need to peel the 'wax-paper' off before mounting the gasket
2) Make sure the spout coming off of the new rubber fitting is angled downwards, probably a 35 or 45 degrees angle. This enables any water to drip down the spout off the fitting, down the rubber hose and into your drain
3) Clean off the remains of the old gasket from the back plate before putting on the new one. You want the new gasket to have a good seal. Use some type of solution to remove the left-over glue from the previous gasket.


I have uploaded a picture of the old inducer before I removed it, and after. I also labeled the parts that came with the new package.

If you are noticing a really bad squeaky sound coming from the furnace and it usually happens right away when it kicks on, and then goes away after it has run for a while (but sometimes it will start at arbitrary times) then the squeaking you get there is actually the blower body vibrating on the bolts that held it in. Put a hand on it, it'd stop. A little oil around the screws & it stopped. Comes back about every three years or so; pull dust off, oil again.

If your furnace is making a loud growling/grinding sound when turned on .The sound is louder on high. and when you run the heater on low, it makes the sound off and on then it no longer makes the sound after awhile then you have a fan blade hitting something inside the unit, or the motor is going bad. That's the only moving parts to the unit unless it has a sweeping mode, moves from side to side. If it doesn't have that, then it's your fan motor or blade. You probably need to replace the motor or the whole unit, as they are fairly inexpressive.

If you are having a humming noise, similar to the hum you hear near an electric transformer box, coming from an idle heat pump's1987 York air handler. Then to your knowledge nothing is wrong when you get humming from a transformer unless it is unusually loud. They all hum. Now if it changes to a hum to a rattle, then change the transformer.
Sometimes the noise is not the transformer but the mounting is loose and just amplifies the noise. Sometimes they get louder just before burning out... but not always.

Is it time to replace your furnace? Fill out a Repair or Replace Report Card

List of Noises 10

• Boom/banging noise
• Growl noise
• Clicking noise

If your 1992 Lennox Elite G26 series furnace when it turns on and ignites the gas it makes a boom/banging noise then pull the burners and clean the crossover slots with a file or thin screwdriver and flush them with hot water.
There were a small number of these furnaces that the heat exchanger cracked by the right burner as the burner manifold was a bit off center from the factory. Very few but that can cause a burner misalignment. The heat exchanger and manifold had a warranty. Also you can check the manifold gas pressure or meter clock it to make sure it is not over fired. You need a experienced tech to adjust the gas pressure as there is a special procedure due to it being a modulating valve.

If you are noticed that your furnace was rather noisy - when it would first start up, it had sort of a growl to it, and there would be a clunk at which point it would quiet down to a reasonable hum, then shortly after it would light, and the blower would follow, then the inducer motor is the source of the noise. It has two speeds, and the clunk is something getting hung up when it is switching speeds, in this case the inducer motor should be replaced.

However, it must be done right, otherwise furnace wouldn't run at all. It may, however, make an electrical-sounding hum. It could be that when the repair person made a gasket for the motor out of silicone, he put on a bit too much, which oozed inside inducer. As the silicone started to set up, it glued the fan to the housing, so it couldn't move. The housing on the motor at this point could be very hot because the motor had overheated and shut off automatically.

In order to fix it the repair person may scrape out the silicone that was sticking things together, although some remained on the blades of the fan. After he put everything back together and the furnace worked once more, you can noticed that it seemed pretty noisy on startup, although not like the old inducer - this is more of a vibration than a growl, also you can actually feel the vibration in the floor of the room above the furnace. It all happens because the silicone left on the blades has made it unbalanced, and that is why there are so much vibration. So at this point you should ask for a new motor to be installed.

If you have a Nordyne M1M furnace that has an issue with the gas valve.. When the gas valve clicks on it clicks off 3 times in a row every time it starts. The furnace stays on and heats up like it should but the gas valve clicks on and off 3 times in a row and then stays open and everything is fine after that. Then it could be an inducer motor. It’s might be corroded and stuck so you can clean it, and order a new one.