Bathroom fan mod

[wyleyrabbit]

I am constantly annoyed at how loud the bathroom fan is in our Bighorn. The other fans are great, but that crappy little fan in the bathroom is ridiculous. I shouldn't be able to hear it from the recliners in the back of the rig.

I admit that I'm one of those "silence is golden" kinda guys, and I'm particularly sensitive to fan noise. Perhaps this is because of all my years dealing with computers (sometimes loud) and servers (always ridiculously loud). I have gone to great lengths to ensure my main computer that I sit at for sometimes 10 to 12 hours a day is as silent as possible. Heck, I even blogged about this here: http://chrisyuzik.posterous.com/silence-is-beyond-golden

Now, back to our Bighorn. That blasted little fan drives me crazy, notwithstanding the admittedly short trip that must be. Computers have 12V DC fans that can move a lot of air without making much (if any) noise. One can pick up a 12cm case fan that can move 40 to 70 CFM almost silently, and 14cm fans can move even more air just as quietly. Furthermore, computer fans probably do this with far less power consumption, which might be important when boondocking.

I asked our dealer about this, hoping that perhaps the fan was defective and could be swapped out for a better one. Apparently, this is just the way the fan is.

I suppose this mod, which is still in the planning stages, will require the removal of not only the existing fan, but also the big gray metal box that contains the switch. Then the new fan (or fans) would be installed along with a simple switch.

Has anyone done anything similar? Any thoughts or advice?

Cheers,
Chris

 

[mrcomer]

Hey Chris,
Neat idea of yours. I ended up replacing my junky fan with another Fantastic fan like what I have over the kitchen area. Still a bit noisey but much nicer that what was there before.

Please take some pictures and post them when you have finished your mod.

Good luck,
mark

 

[Riverman]

Hey Chris
We also had one of the extremely noisy / annoying type bathroom fans in our last unit.
Had we kept the trailer, the plan was to excavate it and replace it with a "Fantastic Fan". We had a fantastic fan in the bedroom which was significantly quieter and moved lots more air volume.

 

[caissiel]

Most good quality fans are 120Volts.
But its a 12volt fan and the wiring to the fan is only 12volt,
Wow I did not realized how many 12volt options there are.

 

[Riverman]

Most good quality fans are 120Volts.
But its a 12volt fan and the wiring to the fan is only 12volt,

Laurent - were you by chance an electrician in days gone by??
BTW...Fantastic Fans come as 12V

 

[wyleyrabbit]

Most good quality fans are 120Volts.
But its a 12volt fan and the wiring to the fan is only 12volt,

Computer fans are all 12V DC.

 

[caissiel]

I was in engineering for 15 years and then in management for the remaining 20 years, supervised all trades, and designed many industrial equipment. My motto was always fix it better then it was running before.
Saw all the improvement in the electrical, instrumentation and computer technologies.
Mechanical never changed much, just the tools for preventive maintenance improved a lot.
The Bearing manufacturers always told me that bearings never fail, the environment around the bearing cause the failures.

 

[RoadJunkie]

Does the "noise" originate from the 12vdc motor (bearings, non concentric or unbalanced shaft, etc.) or from the air-moving fan assembly (unbalanced blades, cavitation, etc.)?

 

[wyleyrabbit]

My assumption is that the noise is generated by:

• vibration from the fan propeller and tiny little spindle
• the small diameter fan propeller spinning really fast, hoping to move air
• may also be the design of the blades

I suppose if there were an easy way of really dampening the noise from the bathroom fan, I'd consider doing that first.

I found a video review on a 14cm fan from a company named "Noctua". Not sure if this would fit in the available space between the edge and the roof vent crank. I'll have to do some measuring and see. The fan kit also comes with power adapters that have resistors inline to allow running it at lower RPM.

Details can be had here: http://www.noctua.at/main.php?show=productview&products_id=33&lng=en&set=1

Looks like at full 12V DC power moves about 65 CFM with only 20 dBA of noise; that's far quieter than someone whispering. Furthermore, it has an MTBF of > 150,000 hours or about 17 years of continuous usage.

The review is here:
http://www.youtube.com/watch?v=nmltrRw7YXk&feature=player_embedded

The local computer shop also sells a different brand called Scythe (model #SM1425SL12H) for a few dollars less that says it moves 92 CFM at only 36 dBA. A noise volume of 36 dBa is somewhere between the volume of a quiet library and a quiet room. I can deal with that!

I haven't put a sound pressure meter on the current bathroom fan (yet!), but my guess is that it's somewhere between 60 and 70 dBa.

Chris

 

[RoadJunkie]

Nice review on the Nactua, the young man is a natural at product overview. One element he touched on was the mounting option that isolates the fan and reduces transmitted vibration noises. I suspect this is a huge factor in the noise generated from the stock fan.

If you figure out how to mount such a beast take some pics and keep us posted.

 

[caissiel]

When I was in to purchase a bathroom exhaust fan for the house, there were at least 4 or 5 that I could try that were assembled in the store display. I surely tried them all and choose the quiet one, the noise of the fan were in proportion with the lower prices. There must be more expensive fan with silent bearings on the motor available.

 

[wyleyrabbit]

Ya know, I asked my dealer that very same question, and unless I want to drop a bag with a big "$$$" written on the side for a Fantastic Fan, they couldn't help me.

Big R&D spent by some of the computer fan companies. We'll see.

 

[porthole]

Fantastic fan. Solved a couple of things for me.

Quiet, variable speed, thermostat if wanted and the main benefit - a rain sensor.

 

[wyleyrabbit]

Hmmm. We have vent covers over all of our fans, so even the two rain sensors we have don't do much for us.

I have no idea how much air the existing fan can move, but I've gotta do something.

 

[porthole]

When I was in Elkhart picking up the trailer I went for a ride one day. I turned the AC off (I was at the service center) and turned on all three fans as it was a warm day.

Of course during my running around a thunder storm blew through.

Two fans closed their lids and the bathroom fan let the floor get wet.

So the next time out I picked up a Fantastic fan for the bathroom.

Are you using vent covers on the fantastic fans? I thought it was recommended not to.

 

[wyleyrabbit]

Maxxair makes special vent covers designed specifically for the fantastic fans. Our dealer not only recommended these but threw them in on the deal, although I had to install them. So yes, we have covers over all of our fans.

 

[caissiel]

I had vent covers on all my vent in the last trailer. Took them all off, because they were cutting the light and were cutting of air circulation. I never travel with the vents open because it sucks exhaust fumes from the truck.

 

[TXBobcat]

When I bought my trailer I had them replace the cheap fan in the toilet room. It is different than the one in the kitchen. It will move air either in or out. The Kitchen Fantastic fan will only move air out. I have MaxAir vents over my fans. The ones over the fantastic fans are made especially for them. I put the vents over the fans because wind beats them up a lot and I don't want rain to come in when they are closed.

When traveling in the summer I might leave a vent open and a window in the back of the trailer to keep an air flow through to keep it cooler.

I know the fan company does not recommend covering the fans, but if you don't I think the covers are very easily damaged by wind when driving or when staying in a campground.

BC

 

[jmgratz]

We have had a MaxAir vent cover (made for the Fantastic Fan) on ours for several years without issues. That way we can use it even in the rain.

 

[caissiel]

In 17 years and 3 trailers I have changed 1 vent cover, so that is not a concern for me. Never saw any rain come in when closed.
We hardly use the A/c neither so we do open the vent a lot, the fan hardly is on also. Love our kitchen fantastic automatic temperature fan though. still debating about the bedroom vent, might just put in a fantastic fan there to and no A/C.
The old trailer had 2 doors and ventilation was great in the hot weather. This one will need the fantastic fan too replace the 2nd door.