Bathroom Fan smoked - again!

[EddieTheWire]

Anyone else have a problem (after problem after problem) with the bathroom ventilation fan in the Interstate?

I barely had our 2012 Lounge for 3 months and it quit - dealer said a diode needed replacing in the fan/motor. A diode for a DC motor with a switch? Okay, well...so now it works again.

Died again after a couple years, but still under warranty so the whole unit was replaced by the same dealer.

Now here we are just 2 months outside the 3-yr warranty and we smell the burnt wire smell of another dead fan.

Any suggestions on where to get a replacement fan (or maybe just the motor? or diode??)?

Do I need to scrape all the goop off the roof to remove/replace it from above, or can I do the whole deed from inside the bathroom?

thanks in advance...

[kennethowens]

Sounds like too much motor for the wire size
or bad ground connection at the motor location.
Low voltage...due to a current limiting cause...such
as a bad ground at the fan - will cause overheating
and failure. Look at the wire also...if insulation is slightly
melted...the motor is wanting more current(wire size &/or
source voltage) or it's a bad ground. Supply voltage
drops when the motor is turned on. If the supply voltage
drops >10% with motor running....ya may have source
issues.

Easiest thing for a dealer to do is shove a new part in the place
and write it up in warranty. Masking the source problem.

Low current flow looks & smells like overload.

May not help...but sticking a new motor into the same problem
didn't help either.

Symptom of problem is not the source of problem.

[Protagonist]

My bathroom fan lasted three and a half years before going kaput during the WBCCI International Rally at Farmington. I was at happy hour at the Vintage Airstream Club tent when a sandstorm blew in, so I wasn't in the van to shut off the fan and close the vent, and the fan motor gave up the ghost after it swallowed too much airborne dust. Didn't even blow a fuse, just after the sandstorm the motor wouldn't turn anymore. Had the dealer replace it while the van was at the dealer for other work.

[UKDUDE]

Originally Posted by Protagonist

My bathroom fan lasted three and a half years before going kaput during the WBCCI International Rally at Farmington. I was at happy hour at the Vintage Airstream Club tent when a sandstorm blew in, so I wasn't in the van to shut off the fan and close the vent, and the fan motor gave up the ghost after it swallowed too much airborne dust. Didn't even blow a fuse, just after the sandstorm the motor wouldn't turn anymore. Had the dealer replace it while the van was at the dealer for other work.

My bath fan has gone kaput too - after a thin sticky-backed sealing foam came unstuck and wrapped itself around the blades. Is this covered under the standard 3-year warranty? I don't have any paperwork for this in my kit of instructions and no model identification is visible.


Sent from my iPhone using Airstream Forums

[AtlantaCpl]

I found a unicorn. A service tech that not only knows Interstates back and forward but the work ethic to diagnose the real problem and address it. He works for RBM Mercedes dealer in Alpharetta Georgia which is an authorized repair facility.

Root cause - lousy workmanship at the airstream point of install. The wires for the fan run between the outside of the fan housing and the frame. Guaranteed you will find the insulation was damaged during install or vibration during trips and shorting, causing the diode or switch to burn out. 5 minutes to add electrical tape and carefully place the wires are causing hundreds of these to fail. God I hate capitalism sometimes.

Don't just fix the switch or diode, force the tech to show you how the wires are shielded from shorting against the frame or housing. In the case of mine, the damage to the insulation was very difficult to spot until the tech shined a light right on it. He predicted it was there and sure enough it was.

Brian

[BrianKrueger]

Originally Posted by AtlantaCpl

I found a unicorn. A service tech that not only knows Interstates back and forward but the work ethic to diagnose the real problem and address it. He works for RBM Mercedes dealer in Alpharetta Georgia which is an authorized repair facility.

Root cause - lousy workmanship at the airstream point of install. The wires for the fan run between the outside of the fan housing and the frame. Guaranteed you will find the insulation was damaged during install or vibration during trips and shorting, causing the diode or switch to burn out. 5 minutes to add electrical tape and carefully place the wires are causing hundreds of these to fail. God I hate capitalism sometimes.

Don't just fix the switch or diode, force the tech to show you how the wires are shielded from shorting against the frame or housing. In the case of mine, the damage to the insulation was very difficult to spot until the tech shined a light right on it. He predicted it was there and sure enough it was.

Brian

We went to the same dealer (RBM of Alpharetta, GA) and our nonworking fan was diagnosed as being completely kaput--and this with our rig being just over 1 year old. And, unfortunately in our case (since our rig was a manufacturer buyback due to a lemon law and therefore no longer under warranty per Airstream), it would be a $450 repair. We declined. Not worth $450 for a fan that would be seldom used. And, it appears, may end up just failing again in the near future.

[EddieTheWire]

btw, why is there a diode? DC flows one way only. Maybe they fear someone will wire the fan backwards and it will suck air INTO the bathroom instead of exhaust the air?

[Protagonist]

Originally Posted by EddieTheWire

btw, why is there a diode? DC flows one way only. Maybe they fear someone will wire the fan backwards and it will suck air INTO the bathroom instead of exhaust the air?

Actually, yes. The 12vDC motor itself is inherently reversible, but is being used for an exhaust-only application, so standard practice is to include a diode to ensure the fan attached to the motor is used as an extractor fan only. The same motor can be used in other industries for other applications besides just extractor fans, where the diode might be replaced by a three-way switch to allow forward/off/reverse.

[TCwheels]

Originally Posted by Protagonist

Actually, yes. The 12vDC motor itself is inherently reversible, but is being used for an exhaust-only application, so standard practice is to include a diode to ensure the fan attached to the motor is used as an extractor fan only. The same motor can be used in other industries for other applications besides just extractor fans, where the diode might be replaced by a three-way switch to allow forward/off/reverse.

This is shaded pole motor or "c" frame motor, correct? Costs between $5-$10 dollars from the manufacturer. How on earth can the repair cost $450, I wonder?

[TG Twinkie]

I doubt it is shaded pole. They are AC motors. Chances are good that it is a permanent magnet DC motor. Not sure what the diode is for. Other than to protect the fan from reverse polarity. Most DC permanent magnet motors use a Hall effect switching system instead of a commutator and brushes. The diode protects the circuit board would be my guess.

[AtlantaCpl]

My theory is the diode is there in case someone left the dome up while driving 70mph down the freeway. Whether the fan is on or off that could back flow current into the circuit. The inverter probably doesn't like a current coming in this fashion, and could make very unpredictable behavior or blow something out.

Brian

[gmillerok1]

Originally Posted by BrianKrueger

We went to the same dealer (RBM of Alpharetta, GA) and our nonworking fan was diagnosed as being completely kaput--and this with our rig being just over 1 year old. And, unfortunately in our case (since our rig was a manufacturer buyback due to a lemon law and therefore no longer under warranty per Airstream), it would be a $450 repair. We declined. Not worth $450 for a fan that would be seldom used. And, it appears, may end up just failing again in the near future.

If this is the same model you can buy a replacement motor from a dealer:

http://ventline.com/home
http://ventline.com/i/u/6148923/f/RV...Vent_11-11.pdf

http://www.etrailer.com/Accessories-...VD0218-00.html

or

http://www.etrailer.com/Accessories-...VD0218-00.html

or just simply replace the complete unit:

Amazon.com: Ventline VP-543 12V Smoke Van Roof Air Vent: Automotive

For the motor only replacement you are only out 20 bucks.

I would find a more honest dealer, buy the parts yourself, and have it replaced. Actually, I would simply replace it myself. It is not that difficult. Here is a good tutorial:

https://boldandadventurous.com/how-t...our-airstream/

[jgeurin]

Well, I had the same issue come up. The diode is apparently fried. I just removed it. I plan to be careful about closing the vent on the highway, and just living without it.

[Paprika]

Just speaking from general knowledge:

1. It's a DC permanent magnet motor, so as long as it was wired correctly at installation, reverse polarity will never be an issue.

2. Similarly, if the fan is wired correctly at installation, it can never run backward even without a diode.

3. The Ventline fan has no circuit board to protect.

4. Back flow DC current (due to fan acting as generator) could not damage the inverter, because the inverter's output is connected to 120 VAC, not 12 VDC. In other words, DC cannot flow into the inverter's output terminals.

Aside from that, if the fan is switched off, no power can get through to the rest of the coach. The switch is an open circuit.

5. A diode causes a 0.6V voltage drop. Removing the diode will let the fan run a little faster and more efficiently.

If this happened to me (and it may someday), I'd simply jumper around that unnecessary diode. Just my two cents' worth... :-)

[Pahaska]

I have a muffin fan all ready to install in place of the original fan. It will be quiet and will not roll the TV like the crude original fan.

I simply knocked the corners off a 5" muffin fan to fit in a 6" circle and built up the sides of the fan with foam to a round shape. I'll put some heavy-duty mounting tape on the two flat plates that the original fan was mounted on and press the new fan into place. It will be a tight enough fit in there that it should stay nicely in place.

I'll probably put it in next week.

[Hein]

Maxxair has a nice vent that might be better:

https://www.airxcel.com/rv/maxxair/p...s/maxxfan-dome

We will have them in stock soon.

All the best,
Hein
DIYvan
541 490 5098

[Pahaska]

I had been putting off installing the modified muffin fan I posted about above. Since I can work on the AI and stay sequestered, I am catching up on a lot of chores.

I decided that the MaxxAir fan linked in the post immediately above looked like a better option than the muffin fan. The fan was delivered yesterday and I installed it today.

I like the built-in light in the fan. I installed the bottom trim so that the pushbutton for the light was angled toward the door so that it is easy to punch the light on when entering at night.

It took me a lot of trips up the folding ladder to cut away all of the sealants around the old fan. The rung spacing on that ladder is very large and that makes going up and down a real chore at my age. I probably made 15 trips up and down that ladder.

Airstream had installed a raised base with a rubber gasket so that installing the new fan was very easy. The new fan is very quiet and the built-in light is great. This is what Airstream should install.

[Pahaska]

The best feature of the MaxxFan dome is that it has a centrifugal fan that naturally exhausts out the 360-degree slot that is opened when the lid If pushed up.

The fan I removed had (before the blades disintegrated) a propeller-type fan that blew upwards against the lid. You couldn't design a poorer airflow. I'm sure that is why the fan had to sound like a plane taking off in order to move much air. The new fan is very quiet.

The remains of the original blade crumbled in my hands when I removed it. Absolutely no UV tolerance.

[2Dreamin]

Pahaska

I am looking at the brochure on AirXcel for the MaxxAir Dome Vent, it says it is for a 1" roof and that extensions are available up to 6". Did you replace the entire fan assembly (new flange). Was there any extensions included when you received the fan?

[Pahaska]

Originally Posted by 2Dreamin

Pahaska

I am looking at the brochure on AirXcel for the MaxxAir Dome Vent, it says it is for a 1" roof and that extensions are available up to 6". Did you replace the entire fan assembly (new flange). Was there any extensions included when you received the fan?

My Dome Vent came with the extension. I am very pleased with it. It is super quiet and does not tear up the TV when running. My only gripe is that the ceiling in the loo is not flat and light leaks from around the top edge. One of these days, I'll get around to putting a gasket around the top and stop that.