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My profession is a ductwork installer, also I’m installing new equipment such as furnaces, humidifiers, air filters air conditionings and so on. Sometimes I’m doing system balancing, noise reduction in ductwork, and a minor furnace repair. So, I don’t have very good knowledge in furnaces servicing and all aspects of their noise reductions. It is why I decided to create this page. If you found this page on the web don’t go any further: I did all the research for this topic for you! I’m hoping if you find a description of your problem here you can stay on my website and check out what I’m offering to you.
List of noises:
Buzzing noise
Clicking noise
Grinding noise
Humming noise
Moaning noise
Noisy furnace
Random noise
Rattling noise
Rumbling noise
Squealing noise
Swoosh noise
Train like noise
Vibration noise
Whining noise
So here we go:
Furnace squeals
Squealing sounds from a forced-air furnace generally occur when the belt that connects the motor to the fan slips. If the blower is making a grinding noise, shut off the unit and call a furnace repair technician, the motor's bearings are probably shot.
In most cases, the belt is improperly aligned or worn and needs replacement. Follow the instructions in your owner's manual (if you don't have one, contact the manufacturer and ask for one).
This job involves removing the access panel, loosening a couple of bolts that hold the blower motor at the proper tension, and realigning or adjusting the belt. In many cases, it's a good idea to remove it and buy a replacement at the hardware store.
When reinstalling the belt, be careful not to over-tighten it this can wear out the motor bearings.
Furnace rattles
If the furnace makes rattling noises when it runs, be sure the cover panels are screwed on tight. If they aren't, tighten them.
Question
We live in a new house (built 2005) with up and downstairs furnaces. In the
last month, after the heater shuts off, we can hear a fairly loud buzzing
through our wall in our bedroom. I noticed the same noise in the living room
wall (same side of the house). I turned the thermostat to "off" and the buzzing
sound went away. Any clues?
Answer
A buzzing noise from a furnace is fairly common and is usually taken care of by tightening the mounting of the transformer. The unusual thing that you describe is that setting the thermostat to the OFF position stops the noise. Since nothing typically happens on any furnace until the thermostat calls for heat, it is unusual that setting the thermostat to OFF would do anything at all.
When you hear the humming noise, remove the cover to the burner compartment of your furnace. Try listening to hear which control or component is making the noise. If you find something that is humming you can usually get rid of the noise by tightening the mounting screws. In some extreme cases I have had to put a small piece of cardboard or plastic under the item and remount it.
If you don't hear anything in the burner compartment, you will need to remove the panel to the blower compartment. When you do this a door switch will open and cut off power to the furnace and stop the noise. Press the switch back down and listen for the noise. If you are able to figure out where it is coming from try tightening the mounting.
Needless to say, before you remove a control and try to remount it, be sure to turn off the power to the furnace.
Question
I recently had a Goodman high efficiency furnace (Model #GMV90703BXA) installed to replace my old furnace in a 25 year old 1900 sqft. Split level house. It is installed in the laundry room on the lower floor of the house. When it is on there is a loud whining noise on the upper floor above where the furnace is. When standing beside the furnace it sounds normal. I had the installer back in to check it and after doing nothing but look at the furnace for a few minutes, told me that it sounded normal. He didn't even go upstairs where the noise is. This is keeping my family awake at night so any suggestions would be really appreciated. Thanks.
Answer
Not good. I would turn off the furnace & turn on the blower only. This is high speed. Still hear the noise? Yes. Take off the lower panel on the furnace, trip the power switch to run the blower & see if the noise stops. If so, it may be air noise from a leak around the furnace base. When the panel is reinstalled & the blower running, go upstairs & listen to see if the noise gradually subsides as the blower slows down when the blower is turned off. If so, it is an air leak somewhere. If that doesn’t locate the noise I would turn the blower off, turn on the heat & check the combustion air blower motor inside the top panel for noise. If still have the noise it may be in the plenum on top of the furnace which would have been modified for the new furnace. Is it sealed well? Another check would be the return air grille for air noise, or even something in the return air plenum. I think you have an air leak that is projecting the noise up & thru the furnace. Look around carefully for leaks. Nothing inside the furnace should be able to create such a noise. Good luck.
Question
My furnace is approximately 3-5 yrs old (from what the seller told me) and it started making a clicking noise when it was ready to shut down after running a cycle. It runs the full cycle, the blower shuts off then the clicking starts. With the clicking you can also hear it make the swoosh noise it makes when the burner initially ignites, only it comes in several intervals with the clicking. you can kind of see little bursts of flames when it does this several times in a row then it shuts down completely.
Answer
Sounds like you have a clicking gas valve that is leaking gas. Causes could be tricky to find. First, I would check the low voltage wiring for loose terminals. Start at the gas valve & work backwards thru the air pressure switch & on to the circuit board. Next I would remove the hose from the combustion air motor to the air pressure switch, blow thru it to clean it. Then check the switch for obstructions. Next, start the combustion air motor & check for air blowing out the opening for the hose. Now, reassemble & retest the furnace. Next, if not OK, check the wiring at the thermostat for loose wiring terminals.
Question
Hello Dale. I have a Rheum electric heating and cooling system. A couple days ago, it started making a low rumbling noise. I have very little knowledge of these things, so I started looking for the obvious. First, I checked the outside unit. It sounded normal. The furnace is where the noise seems to be loudest (although it can be heard faintly through the vents, especially the intake, one floor directly above the unit). I started by taking off the panel that covers the compartment which houses the blower. As soon as I did, the rumbling stopped. As soon as I replaced the cover, the noise began again. I experience this whether the thermostat is set on heat, AC, or fan. I haven't really had time to sit around and wait but it seems that the system wants to run longer than usual before shutting off. Any Ideas? Thank you in advance for any help you might be able to offer.
Answer
In response to your question, you may want to check and see if your motor has oil ports if so you may want to try putting a few drops of oil in them if not you might call a service company and have them check the Amp draw of the blower hope this helps you some have a great summer!
Question
I have a high efficiency Rued furnace that was installed in our home when it was built in 1993. In the last couple of the furnace has started to make a noise about 30 seconds before the blower kicks on. It is loudest in the morning when everything is cool after the heat has been reduced for the night. The furnace will start the fire in the combustion chamber and build the heat. About 30 seconds before the blower kicks on there is a rattle noise that can be heard through out the whole house and in the quiet mornings is quite loud. The rattle sounds like a vibrating water pipe if that helps. I've tried standing by the furnace and can't isolate where the noise is coming from. I would appreciate any ideas that you might have.
Answer
It sounds like a problem with the heat exchanger. It may have developed a crack and as the exchanger heats up, it will make sometimes a sound as you describe, or a loud bang when it expands. It needs to be checked ASAP as carbon monoxide could enter the ductwork if there is a crack. I also always recommend a good detector for carbon monoxide with any fuel burning device.
Question
Hi, I have a Hail Gas Furnace with a self igniter. Everything runs good except for a clicking noise that won't stop, it sounds like it's the igniter. When I turn of the gas and unplug the spark plug wire, there is a low humming noise that sounds like it's coming from the control module. I'm thinking there is a problem with the Honeywell control module. What do you think? Thanks.
Answer
Check the flame sensor and make sure its clean. if it still clicks i would think about changing the sensor.
Question
It has been several months now that my gas heating furnace kept making some noise. This noise is random. Whenever this noise occurs, there is no air blowing from the vent on the floor. This noise last the same duration as when it was working fine. My guess is that whenever this noise occurs, the fan in the furnace does not turn.
The furnace brand is Carrier.
Any help will be much appreciated.
Answer
I would first check the blower to see if it was tight and that you couldn't move it to the point where the blower might contact the sides of the housing. At the same time, checks to see that the motor mounting bolts are tight.
Question
Heating season just starting here in Minnesota and when the blower runs there is a new noise the furnace hasn't had in prior years - a mild moaning or groaning noise of a type which makes me think the motor is in the early stages of an eventual failure. I get nervous at the thought of having an emergency service call three months from now when it is 10 below zero. So, here are my questions:
First, is there anything I can investigate further or try myself in hopes of reducing the likelihood of a potential repair call this winter?
Second, if the motor does go or should be replaced now, is this something I could do myself?
Third, this furnace is more than 25 years old. It has proved reliable through that time with minimal service costs, mostly cleaning. Given the age and probable low efficiency of the furnace, is it more cost-effective to replace it? Money is tight right now so that is a factor in balancing the limp along vs. replaces equation. On the other hand, it is an old house and a cold climate and heating per month is high so there clearly could be a substantial payback to greater efficiency.
Answer
Sounds like worn motor bearings. Grasping the motor shaft and moving it up and down (perpendicular to the motor) you should not feel any play. Side to side movement is normal. If all it takes is a new motor to keep it rolling you shouldn't be in for more than $100-$150 if you do it yourself.
Question
My Hydro flame furnace works and heats just great but it has started squealing and sounds like the house is coming down! Is there anything that needs grease? Any ideas? Thank you.
The bushings in the motor are "dry" To go dry they have to be worn out. The bushing material has lube in it. For the bushings to squeal it means the portion of the bushing with the lube in it is worn through. If it is still working you could access the motor and lube the bushings. This is only a temporary fix. I think that once you have excavated and disassembled all the way to the motor you will just replace it. No matter what furnace you have it's a pain. Good Luck
My furnace blower recently started making a loud, low, steady train like noise every time it comes on. It is not a higher pitched squeak, but more like an engine. It is moving air and the cage is spinning. My furnace is supposed to be a perm lubricated motor.
Answer
I am guessing that your blower is a direct drive blower, meaning that the blower wheel is attached directly to the motor shaft. The way you described the noise leads me to believe that the motor bearings are bad. This is the most common reason for noise coming from the blower compartment. About the only remedy to this is to replace the motor. You say that you motor is permanently oiled, that is just a way of saying that it can not be oiled and not being oiled is what causes them to wear out. I don't know what kind of furnace you have but in my area is it is a standard furnace and a regular sized motor and a normal installation the price range for the complete job would be somewhere around $230.00. If you had access to buying the motor and a capacitor you would get by for around about $125 to $150. Post if you need more Information. Hope this helps.
One last thought, with the furnace unplugged feel all around in the blower wheel to make sure that something has not been sucked into the blower wheel and it might be rubbing on something. Use a flashlight and look very good.
Question
Reducing furnace noise?
I'm trying to cut down on the sound coming off our home furnace. I already have the furnace room walls insulated with rock wool, which I find insufficient. Short of adding more wall sound insulation, is there anything that I can add directly on to the furnace unit itself to block the noise?
Answer
It depends on what about the furnace unit is making the noise.
Typically it is the fan motor, or associated moving parts.
Sometimes it is the housing vibrating from the spinning of the blower fan. It may be the plenum or metal (or other) box that the air blows through to get to the ductwork.
Let’s look at all reasons it can make noise and eliminate things
First, the fan. If the furnace/ac kicks on and there is a rattling or grinding or whining or other noise that accelerates as the fan picks up speed, the bearings in the fan blades or motor are going bad. This is not good / expensive to fix maybe.
IF the noise is worse when the fan is at full speed and stays constant while the unit is blowing air it could be that the belt is loose or if no belt the linkage from motor to blower fan is loose or worn out. This may be fixable with a little tinkering but not for someone not mechanically inclined. The mounting for the motor or fan blower may be loose, try to tighten the screws or bolts that hold them down.
If the noise starts slowly after the fan is at full speed it could be that there is resistance in the plenum or ductwork/air ducts/vents. This usually isn't that noisy, but it can be bad.
You should go throughout the house in each room and make sure that the ducts are clear and vents are all open to the full. Usually there are fins that direct the flow to a certain direction these should be open wide, also behind them may be a flow restrictor fins. These are used typically with a lever that opens or close the flow off completely to 'zone control' the room. These should be open wide as can be too for the testing. Should be so the air ducts and vents in each room are open wide and blowing air full when the unit is operating. Be thorough as you search for vents in all rooms, you may miss a vent or two in odd rooms, behind furniture or in larger rooms. If any air vents are open wide and don't blow air with good force (should be similar from vent to vent and from room to room, decreasing slightly the farther from the furnace unit you get) then the ducts (tubes) are blocked somehow. If they are in the attic, they may have been crushed by the cable guy or the Christmas ornaments box you shoved up there. Or maybe you have squirrels building nests within them or something (similar in the basement depending where the ductwork runs.)
If they are smashed, reshape as best you can and see if that gets the air going again. (Careful not to tear them open or cause leaks in the duct itself) If too much air is restricted from coming through the ducts it can make the unit noisier. If the ducts leak into the attic or basement you lose heat/cool into that space instead of the room and could cause water damage from condensation. Seal leaks with duct tape or replace the duct.
Same goes for the return air intake(s) usually there is one at the furnace unit on the door to the unit or an adjacent wall. The filter usually goes there. The filter should be clean and fit properly for the opening so all air goes through it not around the edges. Other return air ducts can be placed throughout the house in larger homes so check that the same as the air ducts and clear any blockages. Sometime when the unit is installed, the unit is too powerful for the size of ductwork existing and this can backpressure the unit causing excessive noise and resultant loss of efficiency of the entire unit. It is working too hard to force air through it. This is hard to calculate, a bigger plenum and more ductwork is required.
Other major noise may be the plenum, duct work, vents or surrounding wallboard or the floor where the unit sits may be loose and making vibration noise that can be dampened by securing it properly/better... if it is rattling or humming it may be the plenum or duct work. Tap on the plenum and ducts to see how loose they are and if so, try to screw rivet or tape the parts that are noisy so they can't flex so much. This may dampen the sound a bit.
Make sure that the floor under the unit is solid and doesn't have any weakness at all.
Sometimes there is water damage from condensation or poorly braced for the weight of the unit or other reasons that weakens the joists or flooring and that can really make it noisy but not be obvious. Unfortunately, this may be an expensive or extensive job to fix but maybe worth the trouble if the floor is damaged enough to break under the unit.
This should eliminate most of the noise of the unit that can be fixed. Sometimes you just have a noisy unit. In that case, there are other things to do to help quiet the environment of your living space.
If the furnace is in a wall that adjoins the bedroom or living areas, you might try to place larger pieces of furniture in front of the area where it is. Like putting your big dresser on that wall right where the furnace is located. Maybe hang a tapestry on that wall as well will help quiet it some.
Move the bed or your sitting chair to the other side of the room from the furnace.
Another more extensive fix can be to double up the drywall board around where the furnace is to quiet it down. This seems radical, but it will reduce a noisy unit significantly if done properly. (Last resort stuff)
In short, Eliminate any vibration noise, air flow restriction noise, or structural weakening, use sound barriers in the rooms or consider replacing the furnace altogether.
OK. There are no more good answers on the web. Of course you can register on some forums and try it there. But before you go please check out the other pages on my website! Participate in the Quiz! Watch video clips on You Tube! Have fun! Let me know what you are thinking about my website! But if you have some kind of different problem with a noisy furnace, and you were able to resolve it some place else please let me know and I will publish it on this page. Help me to help others!
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