Propane heater blower fan motor

My wife called me this weekend while I was at work telling me our heater wasnt working and had a terrible noise when she would turn it on. So when I get home we flip it on and sure enough when the heater kicks on it sounds like something grinding or flapping real fast coming from under the cabinets or bath area. I have a feeling the fan motor has failed. Does this sound like im on the right track? I have been searching for threads on this and havent came up with much so far. How would I access the fan motor to see if this might be the problem? The RV is a 2012 heartland 3650RL

Thanks,

Brad
 

wingfoot

Well-known member
Have you got a screen over the exhaust to keep dirt-dabbers out? Sounds like you have dabbers that have built a mud-nest on the squirrel cage fan..common problem in our area..hence the exterior screen on the exhaust port on the exterior. You can take the cover off the outside and I believe you will be able to see the fan and see if you got any dabbers that have built nest...they love to build them on the fan blades..

Good luck
 

brianharrison

Well-known member
Typically there are two squirrel cage fans, driven off one motor - one is for combustion air (and Larry refers to above) and one for circulation air - either could be off balance, a broken piece on the cage, or the whole cage is misaligned and hitting the stationary cowlings inside the furnace.

Either way, you are going to have to crawl into the space where the furnace is located to troubleshoot - or call out a mobile RV tech. Access is usually through the basement wall.

Here is a quick link to HOM page Suburban furnace - exploded view in Figure 10 #38 is the combustion air cage, #52 is the circulation air cage.

Hope this helps,
Brian
 

Pizzadigger

Active Member
You should be able to access the blower motor from the outside. I had to replace the blower motor on my last TT and that's how I accessed that one. Bearings went bad and furnace squealed and screamed till I replaced the motor. Pretty easy to figure out and replace.



Hope this is helpful. Andy
 

jimtoo

Moderator
We have dirt dobbers in South Texas also.. I just did mine a couple of weeks ago.

On your Big Horn you should be able to remove the outside cover.. 4 screws, then pull straight out easy,, don't force it.. it has a tube inside another tube ,, then on the right side you should be able to see the small cage fan. It is kinda hard to see and you can turn it by your finger. You will see the dobber nest I'm sure. You can remove the 8 or 10 small screws in the plastic cover and the outside part will be loose. It will also let you see the fan better where you can clean the nest off with probably a small screwdriver and then use a shop vacuum to get the dirt out. I could not get my plastic cover completely out,,, but I managed to get the dobbers out. Took about 1 hour hauling the vac out and all.

Jim M
 

Lou_and_Bette

Well-known member
Well, I hope you are luckier than we were. I noticed some time back that when the furnace kicked on, the fan ran normally for about 10 minutes and then it sounded like a battery drill that was running down. In other words, it started running slower and slower until it sounded like it was barely running at all. You could hear "pops" every so often, I later found out that this was because it was re-firing every so often because I wasn't moving enough air to keep the sail switch open and the flame would go out, only to speed up enough to re-fire. I finally got a technician out, he check everything and it was decided that the fan motor needed to be replaced. That happened today and I am glad it was them and not me that attempted this process. In my rig, the furnace has to come out to be serviced and hence the difficulty. It took the two of them 30 minutes to get it out...one on the outside and the other going in through the cold air return grate under my kitchen cabinets. The motor took another 30 minutes to be replaced and then to return the furnace they had to reverse the process but had to loosen the drawer rails and stiles to be able to reseat it in the proper place. Another 45 minutes. In all, they were here about 2.5 hours. The good news is that my total bill was only $300 and now we have steady heat and the system only takes about 15 minutes to bring the temp up to desired level instead of the previous 30-45 minutes. So, hopefully the efficiency is increased and my propane usage will go down
 

cookie

Administrator
Staff member
Thanks for the update Lou. I was wondering what the outcome was going to be after you showed the rusty stuff that came out at the Iowa rally.

Peace
Dave
 

Lou_and_Bette

Well-known member
Cookie, actually when we got inside the unit there was no rust anywhere. I think water settled in the exhaust tube and that is where the rust collected. When the old motor was out, spinning the shaft didn't produce any grinding or other noises, just felt like the orbit was elliptical instead of round (if that makes sense). New one s working great.
 

brianharrison

Well-known member
Cookie, actually when we got inside the unit there was no rust anywhere. I think water settled in the exhaust tube and that is where the rust collected. When the old motor was out, spinning the shaft didn't produce any grinding or other noises, just felt like the orbit was elliptical instead of round (if that makes sense). New one s working great.

The "elliptical vs round" is an interesting description, but I can appreciate the intent - as the stator or winding of a motor goes "bad" there is a drag as the winding (and shaft) is rotated a full revolution - typically it is at opposite sides of the revolution - ie 3 and 9 o'clock positions) - presenting your described "elliptical effect".

From my knowledge, this can contribute to why the motor fails, - it takes significant more power to over come the rotational forces (elliptical drag points) possibly resulting in overheating and failure/shutdown if the motor has an internal thermal protection.

Again, interesting description.

Brian
 
Thank you for the answers. I am going to look into this tomorrow and hope to find the problem. I have noticed dobbers flying around looking for a winter home recently as well as lady bugs. I hope this is what the problem is. I can still feel hot air coming out of the vents when I was trying to locate the problem. today when dumping my tanks I removed the screws from the wall and was able to pull the wall free to look behind and what a mess! It looks like a bomb went off under that lol. I will have to be careful to not mess any of the wires up when crawling under there looking around. I had some poison under the front hatch and found 3 dead mice so hopefully its not a mouse nest or corps in there lol. Mobile rv repair techs in this area must be making a killing because I cant get any to come out for under $150 trip charge and $85 per hour. This is why im going to learn about rv heaters!
 

jimtoo

Moderator
Thank you for the answers. I am going to look into this tomorrow and hope to find the problem. I have noticed dobbers flying around looking for a winter home recently as well as lady bugs. I hope this is what the problem is. I can still feel hot air coming out of the vents when I was trying to locate the problem. today when dumping my tanks I removed the screws from the wall and was able to pull the wall free to look behind and what a mess! It looks like a bomb went off under that lol. I will have to be careful to not mess any of the wires up when crawling under there looking around. I had some poison under the front hatch and found 3 dead mice so hopefully its not a mouse nest or corps in there lol. Mobile rv repair techs in this area must be making a killing because I cant get any to come out for under $150 trip charge and $85 per hour. This is why im going to learn about rv heaters!

You should not need to crawl around inside at all. The fan is behind the panel on the outside of the unit.
 
"Fixed" Propane heater blower fan motor

Ok just wanted to say thanks for all of the replies. I fixed the heater. I was only able to slide the furnace about 7 inches out of the side of the RV due to the duct work hanging up behind the furnace. This was enough for me to see that I had a dead mouse inside the metal wheel that spins. Evidently since he was stuck in the grate of the wheel it was throwing it off balance as it spun. I did also see the start of a dirt dobber nest so I cleaned that out as well. I didnt have much fun pulling the mouse out lol but sure was happy it wasn't a bigger issue. Thanks again.
 

Phil Smith

Retired South Carolina Chapter Leader
Re: "Fixed" Propane heater blower fan motor

Guess he just couldn't keep up with the power wheel. lol
 
Re: "Fixed" Propane heater blower fan motor

I wonder if my efficiency will go down now that i have to use electric to turn it instead of the mouse power LoL. Merry Christmas.
 
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