Buzzing Nordyne

[opie77]

I had my new furnace installed over the weekend. Works great! Doesn't seem to run as long as the old one. But one thing driving me nuts is how loud it is. When the main blower comes on it hums/buzzes pretty loud. Not like a bearing/bushing noise. If I push on the squirrel cage housing, some of the noise quiets down. Like there should be a gasket between the housing and furnace. I also noticed there are no rubber isolators between the motor mounting brackets and the housing.

Its a Nordyne M1MB 077A AW.

Anything I can do?


Thanks!!

[Robert]

Hi,

Call the installer or you'll void the warranty. Buzzing could be faulty transformer.


Not all the mounting systems have the rubber bushings.


I was about to inquire again about your question earlier concerning door and coil cabinet.


This is our busiest time of year and sometimes info gets lost in the shuffle with so many orders and two people handling it all.

Mark is in process of alleviating some of that.



Thanks,
Robert

[opie77]

Thanks for the fast reply.
I should have mentioned in the first post that it is a used furnace. I got it from a neighbor who had the furnace installed Aug 05 then May 07 moved and had the home torn down. Ive had the furnace since May 07.

I had it installed by a local MB repair place. So the only warranty I have is on the install only.

I know it isn't a buzzing transformer. If I press on the blower housing the buzz quiets somewhat. I checked the mounting of the blower motor and blower housing. The motor is tight, and spins freely. The housing is mounted to the furnace by 3 tabs and 1 screw. Seems like there would be a gasket/seal of some sort there.
I'm not sure if its the motor mounts or the housing to furnace that's buzzing/humming as it only does this when the blower is on. Maybe its normal. Its just this furnace is LOUD compared to my older Coleman.


I also received your PM about the coil cabinet. The guy who installed my furnace was able to locate the Nordyne box and door. It was a misunderstanding between him and I. I thought he said he wouldn't be able to get a box and door. He told me he wouldn't be able to get it in time for the original appointment.
But I do appreciate your promptness on that matter.


Thanks again!

[Robert]

Hi,


Blower should be mounted to housing with 3 legs and a screw holding each bracket leg.



You're very welcome, happy to help.



Thanks,
Robert

[opie77]

I figured out the motor was bad. Put a screwdriver to the case to listen, and sure enough it was humming/buzzing.

I replaced it with a Fasco D158 motor from my local furnace store. They said it was a direct replacement. I installed the motor, and now its so quiet you almost cant hear it running.

But for some reason, and maybe I never noticed it before, but when the furnace has ran through its cycle and shuts down, you can feel quite a bit of heat comming from the front of the furnace. Almost like it didnt run long enough after the heat cycle. If I turn on the fan only, it still blows heat from the vents without the flame being on. After a heating cycle finishes and the blower shuts down, I shot the blower motor with a tempgun. I get a reading of 130-140 degrees F.

Is this normal?

The replacement motor is a 3 speed like the one I replaced. I wired the blue/black/red/white the same way. So Im under the impression that it is spinning at the same speeds. The motor is rated for the same rpm as the original. The furnace was, and still is, wired to run at med-hi for heat and low for cool as per the circuit board. It does blow the same out the registersa throughout the house. I guess my main concern is if the furnace still being hot after the heat cycle normal?

[Tipstah]

I have the same furnace and the same problems but mine is brand new only 3 months old. I compained to the installer about how loud it was. When he finally came to look at it he said that the piece of noise insulation beside the blower moter had come loose so when it was running it sucked up against the motor. He is going to replace the motor this week I hope.

I too have noticed that the furnace is very warm after it cycles and had the gas company come out to see if it was safe, he seemed to think that there could be a lot of heat there because thats where the chiminey goes past. I dissagree as it seems to be the squirl cage that is hot after the cycle.
One other thing that I have noticed is our power (electricity) consumption has more than doubled since this furnace was installed as compared the the same time period as last year.
Thanks

[opie77]

Thanks for the info tipstah. My insulation is still secure. So that isn't my problem.

I called the place I bought the replacement motor from and told them about the motor temps. After running the house fan for about 10-15 minutes, you couldn't touch the motor. They had me bring it back for a replacement. Hour later, I have the new motor in and running. Again, just the house fan setting. 10-15 minutes. Motor is too hot to touch. This is also on the LOW setting of the motor. I didn't change any wiring going to the control board. Still runs on low for house fan/air and med or med/hi for heat.

I'm ready to start pulling my hair out over this.

[Tipstah]

I'm not positive the isulation was a problem with mine either I only go with what the installer said and if is is going to replace the motor under warranty I'm gona let him. lol
I am concerned about the heat that is left over after the cyle is complete though.

Tips

[opie77]

Well, I just put my old motor back in. Ran it for 15 minutes on the house fan. Shut it off, and its barely warm. Seems to blow harder too. Ran a heat cycle. Went from 68 to 72. Let it sit for 2-3 min after it shut off. Motor barely warm, no heat coming off from of furnace either.

SO I'm guessing I was sold the wrong motor. I don't know if this place is going to take this motor back to replace it with the right one, or if I'm going to eat it.

[Tipstah]

Sounds like you got it all fixed.
I hope when they put a new motor in mine I end up with all the same positive results. hope you get the refund.

BTW to the mods and admins, Great Site

[Robert]

Hi,

COOL = MED. HI

FAN ON (CONT.) = MED. HI


HEAT = LO



Change those speeds asap.


Thanks,
Robert

[opie77]

Woo Hoo!!

Took the new motor and old motor back to supply house. Told a 3rd guy what was going on. He kept saying it was a furnace problem. After explaining that the old motor worked fine and that it was noisy, he asked a 4Th guy.

Problem was the original motor had a capacitor. The new one didn't. It was under too much strain.

So a 3rd motor is installed. D150 instead of a D158.

20 minutes house fan run time, motor is 85 degrees. It even blows better.


Robert, I read over an install manual from Nordyne. Says on the M1 series 077 to run the heat on medium and depending on tonnage of the a/c either low medium,or high.

http://yaunco.com/pdfs/nordyne/Resident ... nstall.pdf

page 33

Unless its old info. I didn't change the wiring. It is wired for low fan-a/c and med/hi for heat.

[Robert]

Hi,

I had forgotten what your model number was.

Blue wire-Med. Hi = HEAT


Orange wire-Med Lo = COOL


Those can vary depending on a/c.


What tonnage is your a/c ?


Your furnace can have a shaded pole (no run cap) or a PSC (run cap assisted) motor up to 5 tons capacity.


Thanks,
Robert

[Robert]

Looked back over entire thread and seen where you have a 3 speed motor, not 4 speed which is what is shown in service manual for M1MB077 with a/c.


It would still be Blue wire/Med.Hi = HEAT


COOL would depend on tonnage.


Thanks,
Robert