Both furnaces on my 1990 32' DP Regency work great ...plenty of output in this recent 40 degree weather.

My rear furnace has a "squeel" that emits from the housing while in operation.

At first I thought it might be a bearing, but now it sounds more like a "metal to metal", continuous "cricket chirping" noise, like 2 pieces of metal resonating and vibrating [rubbing] together.

...I can't seem to locate the source of this vile noise.

Any Suggestions???

Squirrel-cage fans have close tolerances to their shrouds for efficiency....worn bearings/bushings can allow them to touch. As things warm up, metal expansion could make it more noticeable.

Spinning by hand at low rpm may not reveal anything, but under load with torque & centrifugal force, fan contact with the shroud could be taking place. Any unreasonable side play in motor shaft would be a tell-tale sign.....

Been there, done that with both my furnaces.
Replaced one, & had a new motor installed in the other.

They squealed on startup. It sometimes went away on one, and subsided to chirping on the other. Both got worse over time. When the first one refused to light any more, I pulled it out, decided I didn't want to mess with it. and bought a new one. The second one began vibrating so badly we couldn't use it.

The service tech said the motors have plain bearings with no provision for adding lubrication. Over time, the original lube dries out, & they begin to squall.

In my experience, once it starts, it gets worse not better.

The later model furnaces have a slightly larger housing that makes them quieter, but not a whole lot.

The new furnace was $562.00 including shipping. Motor replacement was $213.00 parts & labor. I removed & replaced both furnaces myself. Don't know what the cost would have been if I let the shop do it @ $65.00 per hour.

Your explaination makes sense.

I haven't dug-in and taken the unit apart just yet ...looks complicated to me, as everything is packed into such a small space.

I will check for side-play in the motor shaft and hopefully, be daring enough to take things apart to further search for the problem ...Thanks for the info!

Replying to Olroy...

This basically describes the problem. Was initially just an occassional "chirp" or "squeel, but now seems to be continuous.

Does it make sense to replace just the motor or is the better suggestion to replace the entire furnace???

There's lots of wires, & if you don't have a schematic I suggest you make one or label the wires as you dismantle it, so they all get back where they belong. Lots of sheet metal screws to gash your hands too.

I'm at the stage in life where such projects are no longer challenges, merely big pains in the posterior.

BTW, when I was a kid growing up in Edina 60 years ago, Shakopee was way out in the boondocks with a reputation as Sin City. Last time I was through in the 1990s, it was just another part of the big Mpls. metropolis.

You got your last post in while I was preparing my last reply.

As to repair, or replace, I'd say it depends on your pocket book. About the only thing to go wrong besides the motor, is the black box control & the ignition system. I don't know what the control would cost, or what's involved in trouble shooting. I do know there's very little room to access any of that stuff, & it ain't no fun when it's cold.

Your rig is the same age as mine with all that implies. With a new furnace at least you get some kind of warranty, & the knowledge that everything is fresh and new. If you're camping in the MN winter, or even in a 40 degree autumn, a new furnace might generate peace of mind.

Olroy, don't let anyone kid you, Shakopee is still a **** hole, wouldn't be caught dead there..

HA HA, just like the rest of the western suburbs they are becoming the Beverly Hills of Minneapolis. It's a very nice city on the river....

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Watch-it Dave! You're a heck-of-allot closer to the **** than I am!

Just kidding!

I know what you mean ...Shakopee is becoming Bloomington overnight. I still live in the old part of town ...kinda locked into a quiet little corner. After 35 years of living here, I'm still tolerating the rapid growth.

I will look into replacement parts and see how hard it will be to replace the motor. Will be putting the coach to bed for the winter within the next few weeks, so this repair may go on the back-burner, as there are many other things that could take priority.

CASH is ALWAYS an issue!

quote:

Originally posted by olroy:
Been there, done that with both my furnaces.
The service tech said the motors have plain bearings with no provision for adding lubrication. Over time, the original lube dries out, & they begin to squall.

In my experience, once it starts, it gets worse not better.

Yup. I had a squaller, too. Used a drop of a mixture of synthetic aviation oil and molybdenum powder mixture. I believe it was Molykote A.

Try shooting in a little Dri Slide first. That will tell you if lubrication is the answer. It penetrates really well and leaves a residue of moly powder. The carrier oil in Dri Slide will go away, but some of the moly powder will remain. That alone might get you through the winter. If it does not, choose between reapplying or mixing up a brew. I used Anderol(that was way before Mobil 1 was on the market, and before I had access to triple nickle)synthetic oil because that was what was available, but another synthetic like Mobil 1 should also do. Synthetic oil has a flatter temperature/viscosity curve and stays in a hot situation longer than dino oil.

We had good results with MolyKote G rapid Plus Spray on valves and actuators on jet hot sections. Never tried it on an RV heater, though. It is a petroleum base carrier, but it is good to 450 C. A bearing house like Kaman should have it.

I am sorry to say that I have no recent experience on heaters, as we removed our furnaces for safety reasons.

Super Lube has a synthetic oil in a pin-point oiler, which should work temporarily.

In any event, if one is just trying to get oil into the bearing, mount the motor vertically, put a couple of drops, and run the motor for ten minutes, or if disassembled, a couple of drops into the bearing itself. reassemble and run for at least ten minutes.

When the motor stops and the bearing cools, some of the oil will retreat into the bearing poores.

Most sleeve bearings are -"permanently-lubricated" (there's an oxymoron). The bearing itself is a porous sintered bearing (made of particles bonded together). The bearing is then impregnated with oil. When the shaft rotates, the slight friction heats the bearing, expands the oil and the bearing particles, and forces the oil out onto the bearing surface. When the motor stops, the bearing cools, and the oil shrinks back into the pores.

If you can get the end-cap off, or the bearing out, you can approximate the impregnation process by heating the bearing in a bath of oil (10W or 5W-XX synthetic preferred) and allowing it to cool. I had an old saucepan that I'd soak the bearing in, bring the temp up to about 250F (if you don't have a thermometer, a double boiler can be used - that'll safely get the temp up to around 200F), leave it there for 10 minutes (watch it the entire time if you're not using a double boiler) then let it cool. Coat the shaft with the oil when reassembling.

I've used this technique many times on things from precision motors up to truck starters. It's not as good as the OEM lube of the bearings, but it'll work surprisingly well.

My forward furnace quit a week or so ago. No fan movement, and it used to squeal some times before. In looking at it, I was surprised to find the gas valve open while the blower was not turning. Could be lots more than a stuck blower. Anyway, I will remove it and look it over this winter after I stop RVing. What I found out is a replacement for this is now available in a multi-speed - multi-btu version for not much more than $50 or so more than the standard unit. It starts high, then switches to low on future cycles. Sounds like it may be worth the investment. Any suggestions on how to remove the furnace?

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89 Barth Regal 32
Runs like a Deere
New Hampshire

Mine were riveted in. I drilled out the rivets, straightened the tabs between the furnace & the cover, stripped off the cover, disconnected the propane line (first making sure the gas was off at the tank, after which I turned on a range burner momentarily to evacuate the line before disconnecting the furnace).

Then I went inside to access the furnaces - 1 under the couch, the other under a bed. There were 2 screws holding each furnace to the floor, plus the wiring and ductwork. The ducts are taped & screwed to galvanized flanges that are removed/installed in the furnace body by twisting them (easier said than done).

I recommend leaving the cut wires long enough so you can splice them easily when you return/replace the furnace (learned that the hard way).

Once everything's loose, the hardest part is keeping the gas line out of the way removing & replacing the furnace, then reconnecting the gas line. That's a flared fitting, and they don't go together if you don't have them perfectly aligned, not an easy task when you disturbed the alignment removing the beast, and only have a finger's width of space to reassemble them.

R & R is a straightforward operation. If you have a good shop with a big workbench you can tear into the machine itself. I replaced one furnace camped on a friend's lot in Yuma. The other one I pulled at home, but a few years ago we downsized from a 28' x 30' garage/shop to a 10' x 12' shed. I don't have room to pull trannys, replace engines, or even overhaul RV furnaces any more.

While the furnaces were out, I taped a piece of Visqueen over the opening to keep the birds & bugs out.

Anything I've forgotten you'll have to learn as I did - the hard way.

Lots of information shared on this topic today and I hope that others are benefitting from this.

I'm a Paramedic and not a Mechanic, so it's a good thing that it will be winter and hopefully I can take my time in troubleshooting this problem ...fixing people appears to be a heck-of-allot easier.

This was my first post today after purchasing my coach off of eBay in early July. I've been reading your posts and learning a ton of information.

Expect to see allot of questions coming from this guy, as I am diesel-illiterate. I come from a short 4 year ownership of a 1977 GMC, so I really look forward to learning allot from you guys.

Thanks Allot!

Robin McCullough
[10 minutes south of Dave Bowers]

Well Robin,

I think we talked once or twice and we haven't got together. You know just in the last year picked up a couple Barth guys and gals here in the MinneApple area. One guy who works with my wife at the Strib bought a 30 foot Breakaway about a year ago.

For all you's folks from elsewhere should know that we are having Indian Summer here and I think it easily hit 70 today. But I think I will be winterizing next week.

Dave Bowers
(10 miles north of Robin McCullough)

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