Furnace Intake Noise

[T and J]

Can anyone suggest any way to quiet the noise from the furnace cold air intake ? So far I have lined the compartment with acoustic tile, that helped but still noisy. I am tempted to close the intake grille below the refrig' and pull the air from inside the kitchen compartments, then cut an intake grille in the far end by the door! Any suggestions? Thanks.

[Montana_2730]

Great question, I have done a few mods myself. I do not think you want to change to bring air from under the kitchen cabinets. The return air grill and thermostat are mutually inclusive. The furnace is just loud when it is on. So my feeling was if I can get the thing to make the air temperature stabilize faster in the Monty, the less time it will be running. On of the first things I did was to take the furnace out and seal beneath it. I did not take any pictures of the area, but I can tell you it was a poor quality installation. Pretty much Keystone people take a circular saw and cut an opening into the duct beneath the floor. My hole in the floor and the furnace opening from Suburban were almost two inches off from each other. The cheap gasket Keystone came up with did not even make a seal between furnace and floor so therefore a lot of air was leaking out.

Keystone only wraps a few single plys of aluminum foil tape to seal gap between floor and inside surfaces of ducting. The tape wasn't even doing its job. So I ran a few screws to tighten the metal duct up to the bottom of floor, and then put three layers of a super foil duct tape around opening. Next was to make a new gasket which I did by buying some foil backed fiberglass insulation and taping it down over the opening. Now the furnace blows all the air down in the the duct and not out under the floor or in the converter compartment. I also tape all the removable 4 inch duct takeoff covers tight which are not used on furnace.

One area of noise you cannot stop unless you change the motor is the sound and vibration the furnace makes when on. The motor/squirrel cage runs very fast and has a high pitch. It also vibrates the floor in the whole trailer. If Suburban could use a slower motor it would help with the sounds and vibrations.

[jsnip42]

Travelingman, how hard was it to remove the furnace? I have what sounds like a leaf in my fan making a annoying noise. I thought it would be easy to pull the grill off and get the leaf. But it appears you have to remove the whole heater to get to the fan. While i'm in there I think i'll do some of the things you did to better seal the heater. Thanks for the idea's.

[Montana_2785]

I also like the ideas presented here. I haven't yet complained about the furnace, I have much larger fish to fry at this point. But I would like to address some of the noise at some point in the future...

Eric

[sreigle]

Travelingman, I'd be interested in hearing what improvements in noise, heating ability, etc., you've noticed since making these changes.

Also, ours does not vibrate the floor. That makes me think something is not right with yours.

Our furnace is relatively noisy, but I figure that's because we're in a small space and the furnace unit is five to twelve feet away, depending on which seat you're in. I know in our stick home when I was close to the furnace in the basement it was quite loud there, too. So all we can do is do what we can to insulate the noise, knowing that in a small space some noise will be unavoidable. So, I'm interested in hearing how effective you think your changes were.

Thanks.

[BillyRay]

makes you wonder of the quality in the items you can't see!

[Montana_2730]

Let me answer question concerning ease of removal of furnace. I can only speak for my 2955. Unplug battery and any other power. Remove the air return grill below the frig. Remove inboard cover from furnace. Remove two screws from bottom of furnace holding it to floor. Remove wire nuts from thermostat wiring. Cut off the cheap wire splices to furnace at the splice (replace later with wire nuts). Remove 2 inch duct outlet an set aside. Protect wood at air grill with masking tape so when you drag furnace out it does not scratch the faux finish. Time to remove 10 minutes pull hard because you have to over come the duct the vent to outside air. Review the quality gasket and hole cut in your floor. Fix accordingly. Below re-installing furnace I removed the outside duct so I did not have to fight lining up the furnace and it. Re-install will take 30 minutes after you get everything sealed up to your liking. Disregard sticker on furnace saying do not remove except if you are a trained mechanic. Reason is, IF THEY HAD DONE IT RIGHT THE FIRST TIME I WOULD HAVE TO BE DONGING IT NOW!!!!! Tie up and clean up the normal things you find with the factory wiring before re-installation.

Total cost to fix:

$2.00 worth of self-tapping screws
$9.00 roll of foil back insulation - Home Depot
$13.00 roll of two inch wide heating duct tape - Home Depot
$15.00 mud dobber screen for outside vent - Camping world
1 hour labor total

There are no air leaks, however, fan noise is still a problem.

[Snowbirds]

I just wish my furnace in our 05 2955 would make a noise. It only worked about a week after we came to Florida in December and hasn't worked since. I've talked to Dometic, Keystone and Surburban, tried their fixes to no avail. Just going to wait till we get back home in April to have it fixed. I don't want to haul it 100 miles round trip to a dealer. Luckily we've gotten by with a small elec heater. That's the only trouble we've had to date. We absolutely love it.

[Montana_2730]

Have you tried replacing the 15 AMP fuse on upper circuit breaker panel. Or make sure the igniter switch which you cannot see is turned on. This switch faces the wall and you would have to remove unit to see it. Two small wires from remote unit enter heated compartment from oven side. Check to see if wire nuts are loose.

[BillyRay]

did you try it on both gas and electric?