Quieting the Suburban furnace model NT-16SE, same as the NT-20SE

[Rustydog]

I know this thread is ancient. But I know many people have trouble with these units. I have fixed about a half dozen of these. Several of them just in the campsite as the problem popped up in conversation around the fire.
Its the electric motor bearings in 99% of the cases.
Of course you should take it to a qualified repair person and I am in no way suggesting one should do the repair.
I fully disassemble the unit to and pull the electric motor apart. Pop the rubber seals off the bearings with a pin-vise and pack with some new SRI or similar grease. Solved.
Yes there is a bit of dis-assembly. I can do the whole job now in about 30 minutes after some practice.
I have A LOT of experience with bearings and it really surprises me how much noise is amplified and resonates from the case when the bearings start getting low on lube.

[cpaharley2008]

Ergo,
The squeaky wheel gets the grease - Wikipedia, the free encyclopedia

[Joe Z]

It sure looks like switching over to an Atwood Everest 8012 II if your Suburban NT-12 E wears out..... Looks like a fairly simple swap but i would imagine the outside air intake and exhaust would be different and require a different hole cutout

[kdhanso]

Hi Scamper Jim and all,

I had saved your write up for future reference and today I got to use it. We just returned from a trip and with colder weather had several mornings where we used our Suburban heater. It vibrated and squealed until it warmed up and then sounded normal.

Now that we're home I took it apart following your details and was able to eliminate the noise. I also heard some sand and removed the back intake housing and found a mud dauber nest. I had installed the mesh covers over my vents but suspect this nest is from the time with the PO.

Thanks for the detailed write up. It works!

[Scamper Jim]

Hi Ken,

It is nice to hear of your experience with my description of the repair process. You are the first to provide feedback of their results even though there have been about 8,000 views of the thread since my original posting.

I figure: 1) some never got as far as my post at the end of the thread, 2) decided to put up with the noise, 3) installed a different heater, 4) were waiting for others such as yourself to do it and see if it is worth the effort, 4) had someone else do the work after seeing the steps and getting dizzy.

As you found out for yourself, it in not a major project as those furnaces were made so they can actually be worked on without having electrical and mechanical engineering degrees.

Just yesterday I returned from a 4-day trip to southwest Colorado area from Denver to Lake City, Pagosa Springs, Durango, Silverton, Ouray, etc. and back home The fall colors of the aspens in the high country were spectacular.

I found out something real interesting on the trip. I don’t know if it applies in others areas or states, but some of the national park campgrounds are still open and are free. No camp hosts, water or trash available, but free. These are regular campsites, not just dispersed camping. One of them is the Silver Thread campground about 20 miles north of Creed. I checked with the ranger station in Creed and sure enough, in fact it stays open year-round, closed only if due to heavy snow. Another campsite at Cimmaron, CO is still open and even has a camp host..

Ergo, it would seem that some of the best camping is after the cg’s officially close the weekend after Labor Day, and then check to see which ones are still open to catch the fall colors. Very little traffic during the week and you practically have the campground and roads to yourself. Be sure you have a good furnace in your camper when in the high country around 9,000 feet that time of year.

[vegas250rr]

question... I am new here so hello,

I just bought my camper and the furnace is not currently working... no noisy fan here, mine is apparently seized. So should the fan assembly spin freely with no power to it much like a ceiling fan? or is that my problem?

thanks for any helpful thoughts in advance

[Joe Z]

The fan may just be stuck from sitting so long not being used..... If you can reach it with a stick or something try to spin it to see if it will spin with no electric to it..... Also be sure you have power to the fan with a test light or multimeter

[vegas250rr]

I tried that, and I cannot get the fan to move... also when I apply power it just pops fuses

[Joe Z]

That's your problem..... the fan should spin free just like a house fan in the "Off"Position.
Just hearing you say it pops the fuse confirms my opinion..... It's a lot cheaper to get a fan for it instead of a whole new furnace..... take the fan out and try to work it free with WD-40 or get the model number and order a new fan.....
Just for a test when you get the fan out put a new fuse in and turn the furnace on for five seconds and the fuse should not blow.
use caution doing that test because you don't want the furnace to light (which takes about thirty seconds) without a fan in place..... just a quick test to show the fuse doesn't blow to confirm the problem

[Carol H]

Originally Posted by vegas250rr

question... I am new here so hello,

I just bought my camper and the furnace is not currently working... no noisy fan here, mine is apparently seized. So should the fan assembly spin freely with no power to it much like a ceiling fan? or is that my problem?

thanks for any helpful thoughts in advance

The service manual for your Furnace is located here.

[Joe Romas]

Jim
The most important part in your write up is the cracked exhaust tube. It can be literally a REAL KILLER!
I tackled my Suburban furnace after first buying our Casita 7 years ago and found the intake tube that on my furnace was spot welded to a plate that mounts on the outside of the trailer just under the chrome plated cover had broken loose and fell into the space in the cabinet behind the furnace. Good thing it was the INTAKE and not exhaust.
I suspect the flexing of the fiberglass bodies from the rough ride is the root cause of the tubes cracking.
My motor bearings were fine but there were many loose or missing screws causing a lot of racket.

Joe

[Scamper Jim]

Joe, that's good feedback on the intake pipe breaking also. There have got to be many more of those furncaes out there with cracked or broken pipes, not just our two.

For their own safety, before owners spend more time with cutsey mods, they should pull their furnace and check for any cracked pipes.

Jeremy,

The fan should indeed turn very freely. If you are not able to find a replacement motor, I have a 1983 Suburban "parts" furnace that I can sell the motor and fan off for a few dollars and shipping.

[Gene L]

Anybody following this topic it is being revived over on my forum with new mods http://www.casitaforum.com/invboard/.../page__st__120
Gene

[jaz89]

[QUOTE=DavidSo;274348]Ok, with the fan out you have this:
Attachment 40771

How easy did your combustion or squirrel fan come out. Mine doesn't budge but a little. Did you have problems or did it slid off easily after removing the hex nut?

[Scamper Jim]

If I remember correctly, those set screws were metric and required a long shank to get between the fins and down on the screw.

Mine came right off after the screw was removed. Maybe a little WD40 or rust buster for a couple of days and it will decide to give up and come loose.

Also, I don't remember if I mentioned it, but I tipped up the end of the furnace and pulled the rubber up away from the shaft on the end of the motor using a dental pick or the like. Then I dripped a couple drops of motor oil into it. Rotate the shaft and let it sit for a day or so, then repeat it again. I don't think there is a roller bearing on the motor, just a bronze oilite bushing. It can use all the oil you get in it and then wipe off the excess. Some will fling off when you run the motor, so just wipe it off before you reassemble the heater into the housing or else it will collect dust on the fins.

Mine has been running nice and quiet hearing only the fan, no squeaks, screeches, etc. when starting, running or stopping.

[Rgray]

Found a quick and easy way to quiet the heater. Installed earplugs at the source.