MaxxAir Fan problems and solutions

[dstefan]

I posted this over on the Ovrlnd Thread, but thought I’d tag it here since so many of us have these fans

Anybody with the Maxxair fan having malfunctions? Evidently a lot do based on my research of my problems, though a cursory search can’t find reports on EP, so thought I’d post my experience in case your’s craps out.

Apparently the fan motor isn’t brushless and uses carbon fiber brushes which shed carbon dust leading to irritating squeaking noises and binding.

My 4.5 yr old fan started squealing in the middle of the night two years ago (I almost always run it all night on low to exhaust condensation). I managed to get rid of it several times by repeatedly reversing the fan direction while running it on high for 5 mins or so. It would run OK for 6 mos or so and I’d have to repeat.

Then it started flashing the green light on our last trip, stop working, and chirp repeatedly until I cut the power. I could reset it by cutting the power and then turning it on and running it from lowest setting to #3. Going to 4 or 5 would immediately start the green light of death and beeping again.

Sometimes the control board is a problem and apparently those malfunctions have to do with corrosion (for older ones) and/or seeing too much voltage when charging and maybe with Lithium batteries and unregulated voltage. Apparently older fans were limited to a max of 13.5v input and also didn’t have a waterproofing, so called conformal, coating on the control boards.

Maxxair CS was really helpful — diagnosed a bad fan motor based on the working up to speed 3 behavior. Told me that newer motors have been redesigned slightly to deal with the problems. Also said the control boards have had the conformal coating for quite awhile now and can handle up to 15v input.

They also said that running a new fan/fan motor on high for 24 hours seats the bearings and helps eliminate the squealing. So with a new rig/fan, this might be worth doing right away.

I just installed the new motor this morning and every thing works great. The control board (which I didn’t replace) looks like new despite once or twice getting some minor rain splashed in and exhausting a lot of moisture (we heat preprepared food and boil water inside under the fan).

The motor is actually fairly easy to remove and install from inside the camper — there’s tons of YouTube videos showing how. Also a bad board is pretty simple to replace too. I could tell my old fan motor was binding up — it was noticeably harder to spin by hand than the new one. I’m going to take it apart later to see if it’s recoverable for a backup.

So if you’re having problems or do in the future, the fix is pretty easy.

 

[Darwin]

If you get it figured out please let me know. I've gone through 4, and all have died. I even tried spraying the circuit board like some have recommended. The first two last 6 months. I then got complete fan replacement x2 and those lasted about the same amount of time. The guy on the phone was also pretty argumentative. It took 8 months for the replacement fans to arrive.

I would recommend if you don't get it figured out to start thinking about other options. I can't express how much I hate these fans. They are noisy, reduce insulation value, allow a lot of sound in, add heat inside when it's hot out and look like they haven't been updated in 30 years.

 

[Roam.Wild]

Ours is about 3 years old at this point and runs basically 24/7 about 8 months out of the year. Besides monthly cleaning never had an issue.

 

[Hegear]

Any idea of when was considered the newer motor design?

Got mine in 22, no matter how many times I clean and run in reverse it starts squeaking again within a few days.

 

[kmcintyre]

If you get it figured out please let me know. I've gone through 4, and all have died. I even tried spraying the circuit board like some have recommended. The first two last 6 months. I then got complete fan replacement x2 and those lasted about the same amount of time. The guy on the phone was also pretty argumentative. It took 8 months for the replacement fans to arrive.

I would recommend if you don't get it figured out to start thinking about other options. I can't express how much I hate these fans. They are noisy, reduce insulation value, allow a lot of sound in, add heat inside when it's hot out and look like they haven't been updated in 30 years.

I've found my maxxfan to be a lot better than the old fantastic fan (bought by dometic I think). Dometic customer service was terrible and tried to blame me for cracked casings/mounting flange, etc. The one thing I liked about the fantastic fan was that if you opened it up manually, the rain sensor still worked. On the maxxfan (my version) you have to use the power to turn it on, etc. to get the rain sensor function and it's a lot harder to manually adjust the vent up/down to the position you want it.

 

[dstefan]

If you get it figured out please let me know.

All I know is I ran my new motor 24 hours on high like they said to seat the bearings and it wasn’t squeaking, but won’t be using it in the wild until July, so I’ll report back

Any idea of when was considered the newer motor design?

MaxxAir CS Rep couldn’t give me a date, but said the new motor I was getting (from eTrailer) would have been the slightly improved version, but she really didn’t know what they did. The motor looked exactly like the old one outside, so who knows. It was made in Dec ’24.

FWIW — I took the old fan apart to see what’s up. Lots of debris in it and could see where the brushes were worn and maybe a mark where it wobbled at some point and brushed the magnet on the side. I got it back together and it rotated the same as before by hand — relatively draggy — so it seems to me the bearings are gummed up. They use sealed, greased bearings, that I doubt got any debris in them, but they’re cheap Chinese, so maybe worn badly, which might explain the fact it was drawing too much current and shutting down, if I tried running the fan over speed 3. Here’s what it looks like inside.







You can see all the debris in the 1st pic before I cleaned it out. The 2nd and 3rd pics show how the brushes are badly worn. I may try replacing the bearings with some better ones I have hanging around to see if I could resurrect this just out of curiosity. I doubt it’s worth it as a backup, but if it would spin as easily as the new one did, it might confirm the bearings were the issue, though not sure what that info does for me . . . It might mean that MaxxAir’s instructions to run 24 hrs on highto seat new bearings make some sense?

 

[Darwin]

I've found my maxxfan to be a lot better than the old fantastic fan (bought by dometic I think). Dometic customer service was terrible and tried to blame me for cracked casings/mounting flange, etc. The one thing I liked about the fantastic fan was that if you opened it up manually, the rain sensor still worked. On the maxxfan (my version) you have to use the power to turn it on, etc. to get the rain sensor function and it's a lot harder to manually adjust the vent up/down to the position you want it.

I agree with you about Dometic 100%. I tried to get parts for a skylight but it was a no go, however hopefully that has changed.

I guess my main issue with both the Fantastic fan and Maxx air fan is that those are basically the only 2 options. I don't think they have been significantly upgraded in 30 years. I also sometimes have a hard time being able to tell if it's exhausting or intaking air it just seems to swirl around in the fan body. For me, I was unhappy with the fans even when they worked, too many negatives.

 

[carterd]

Nomadic appears to be offering an alternative in both a 14" and 15.75" versions. https://nomadicsupply.com/nomadicar...NprRUt6kGiyaFAcj2BHCgys6rg1hvWLhoCYe4QAvD_BwE

 

[montechie]

I've been pretty happy with my Maxxfan in my OVRLND, it creates good airflow for us, enough on the outtake to feel a breeze from our six windows. However, after 2ish years I got a chirp of death. Not sure what happened, but on a trip it started running for 3-4s and then just chirping. It's plugged into a portable lithium battery that I've been using for most of the 2 years.

I finally got around to replacing the control board and added a voltage regulator yesterday. Works like a charm so far, just in time for Montana to switch from 80s to winter storm alerts this late June. It was an easy replacement, I had to cut the power lines, so you'll need a couple new connectors, everything else was plug-in-play. I used VHB to attach the regulator in the fan housing.

For those (like me) who haven't messed with these much and their fan was already installed, you can find the model number on the inside by removing the fan cover.

 

[dstefan]

Nomadic appears to be offering an alternative in both a 14" and 15.75" versions. https://nomadicsupply.com/nomadicar...NprRUt6kGiyaFAcj2BHCgys6rg1hvWLhoCYe4QAvD_BwE

These look like much better designed and spec’d fans. I especially like the brushless motor, which should avoid the motor based issues with the Maxx fans. While the website linked shows them as not available till Aug, I saw that VanToys has them in stock.

I don’t know about the company that makes them, NomadicArk, and couldn’t find any web/forum comments on the fans, though it seems like the company has been around.

Anybody familar with the company or these fans? Are they better known in Van world? I sure would like to have an alternative. . .

 

[dstefan]

Yeah, it’s not good at all. To be clear, the reversing idea came from me, not MaxxAire — out of desperation in the middle of the night when the squealing started I just tried running it back and forth at various speeds and it cured the noise for quite a while. I repeated that a couple times over a couple years. In the end it wasn’t noise that made me replace it, it was that it wouldn’t run over speed 3 without shutting down.

I’m guessing the drag on the motor from the bearings was overloading the circuit board?

Contrast the Maxxfan motor with the NomadicArk fan linked above, ‘course who knows if this is cheap Chinesium too:

 

[Willsfree]

I've been pretty happy with my Maxxfan in my OVRLND, it creates good airflow for us, enough on the outtake to feel a breeze from our six windows. However, after 2ish years I got a chirp of death. Not sure what happened, but on a trip it started running for 3-4s and then just chirping. It's plugged into a portable lithium battery that I've been using for most of the 2 years.

I finally got around to replacing the control board and added a voltage regulator yesterday. Works like a charm so far, just in time for Montana to switch from 80s to winter storm alerts this late June. It was an easy replacement, I had to cut the power lines, so you'll need a couple new connectors, everything else was plug-in-play. I used VHB to attach the regulator in the fan housing.

For those (like me) who haven't messed with these much and their fan was already installed, you can find the model number on the inside by removing the fan cover.

Could you post a link for the volt regulator? My fan shuts off for too high of voltage.

 

[montechie]

Could you post a link for the volt regulator? My fan shuts off for too high of voltage.

Here's the regulator and board I used, there maybe cheaper ones out there.

 

[Fadeagray]

I’ve been using two Maxxaire fans in my habitat full time for six years. Both fan motors have needed to be cleaned once or twice a year due to the dreaded squeak. Recently I found replacement bearings on Amazon. So far they are working well. They are also inexpensive so I will replace them each time I clean the motors.

One note concerning assembly of the motor after cleaning. Bearing preload is important. Too tight and the fan squeaks again.Too loose and the fan growls. I found that tightening the motor screws snugly then backing off just a bit works very well.

Pics below:

 

[dstefan]

I’ve been using two Maxxaire fans in my habitat full time for six years. Both fan motors have needed to be cleaned once or twice a year due to the dreaded squeak. Recently I found replacement bearings on Amazon. So far they are working well. They are also inexpensive so I will replace them each time I clean the motors.

One note concerning assembly of the motor after cleaning. Bearing preload is important. Too tight and the fan squeaks again.Too loose and the fan growls. I found that tightening the motor screws snugly then backing off just a bit works very well.

Pics below:

Thanks — that’s very helpful. I’ve been wondering about whether a rebuild could be functional. Maybe you could say a bit more about the cleaning and re-assembly procedure you find works best? I had real trouble getting my old fan back together. I still need to try it on a 12v source to see if it works at all.

Also, are those bearings sealed on both sides or open on one side as shown in the Amazon picture. I have a ton of old high end, serviceable bearings that would work well, but are unshielded on one side. Been wondering if they’d work with the open side in the cups and not exposed to the debris in-side.

Great info!