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Exhaust fan?

PostPosted: Mon Mar 08, 2010 7:26 am
by timlsalem
Has anybody put their exhaust fan any place else besides the roof? I was thinking of putting it, on my weekender, in the front on the top slope before the roof. I hope that made sence. I figured it to be 26" x 56".






KIA'S--MIA'S--POW'S--DAV'S--are what our freedom cost us

PostPosted: Mon Mar 08, 2010 9:11 am
by john
On my first build I mounted a bathroom vent fan under the camper to avoid any holes in the roof. When we use the tear with shore power, the vent works fine.

It doesn't work without shore power, though. And we can't fall back on natural ventilation .

Re: Exhaust fan?

PostPosted: Mon Mar 08, 2010 9:59 am
by Miriam C.
timlsalem wrote:Has anybody put their exhaust fan any place else besides the roof? I was thinking of putting it, on my weekender, in the front on the top slope before the roof. I hope that made sense. I figured it to be 26" x 56".

KIA'S--MIA'S--POW'S--DAV'S--are what our freedom cost us


I would hesitate to put an opening on a slope as the rain coming down may get in the vent. They are leak resistant when the top is closed but water running down on it can push over the edge..........

PostPosted: Mon Mar 08, 2010 10:37 am
by bobhenry
Auntie M is correct However you could install a rain diverter on the uphill side and divert the down hill flow around the fan.

In the tear I simply open a window in the door and suspend the O2kool fan in front of the window pointed in or out.

If I were to rethink that build I would have made a vent box with the o2kool fan mounted inside and a couple vent tubes running down hill to the outside. ( Think of your car heater)

By changing the hot and ground to the fan you can reverse the flow of the fan. The exhaust mode is not as strong since the blade pitch is designed to blow but it will exhaust.

PostPosted: Tue Mar 09, 2010 10:17 pm
by RichAFix
Great question.

I have been doing a little research on this exact thing for the past 2 days. My thought is since I have about a 3" "tunnel" built between the cabin and the kitchen I am thinking of using a 120 cfm reversible (okay, haven't figured out how to reverse the fan yet) computer fan that can either draw or blow air from the floor of the kitchen through a 3" tube, behind all the cabinets to a small vent (similar to the vent on your car dashboard) on the top of the cabinets in the interior of the sleeping area. My thought is that the air under the trailer would be cooler that I could draw in cooler air or if the sleeping area is getting a little humid/stuffy I could draw the air out (and at the same time force it in from the side windows). Since the vent on the interior would be about an inch from the roof it should draw the hot air out. I am not sure about the "cfm" though, doing the calculation of a standard bathroom fan I am good with a 80 cfm fan but I am concerned as the "fantastic fan" low setting is about 475 cfm. The noise level on the fan I found is in the 43 db level, not sure if that is too loud either.

Not trying to hijack your thread, just trying to toss out one of the thoughts rattling around my brain. I would be interested to hear others thoughts.

PostPosted: Wed Mar 10, 2010 4:15 pm
by Capt. Home Slice
Good topic. I'm interested if anyone has mounted a roof style vent with or without a fan on a verticle wall.

PostPosted: Wed Mar 10, 2010 7:44 pm
by sagebrush
A 12 volt computer fan is reversible by simply switching polarity of leads. Also sucking air out lowers humidity better than blowing in. Something to do with pressure differential. Unless you want a gale force wind don't get too large of a fan as the volume of a 4x8 TD is only about 100 cu/ft. Will

PostPosted: Wed Mar 10, 2010 8:29 pm
by MceeD
I will being using two 120mm computer fans for the exhaust in my TD.

They are native 12v are reversible as mentioned and there are a ton of speed controllers available for them since they are a computer thing :)

Image

I chose to build a tunnel down the side to keep out rain and such. I will only have fans on one side and will build a tunnel on the other side for intake, with a filter to keep out bugs and such.

Here is a couple fans, I will be using the 130 CFM since I will have a speed controller and we sleep with the window open even in winter :-)

80cfm and 32.91dba
http://www.newegg.com/Product/Product.aspx?Item=N82E16835185053

130.6cfm and 45.9dba
http://www.newegg.com/Product/Product.aspx?Item=N82E16835185054

PostPosted: Wed Mar 10, 2010 11:02 pm
by dreadcptflint
MceeD,

I couldn't figure out what you did with the inside of your vents. Do you have some pictures that you could post from the inside? Are you able to seal it from the inside or do you just have the fans in place?

ehhaust fans

PostPosted: Wed Mar 24, 2010 5:21 pm
by Jack manning
Not to horn in, but I have an ac unit in my tear and I use a 10" muffin fan ( the kind used in electrical panels)mounted in the side wall to vent the heated air from the condenser. It consumes .23 amp and moves 640 cfm.I have pic's in my galley. Hoped this helps
Jack manning

Re: ehhaust fans

PostPosted: Wed Mar 24, 2010 6:32 pm
by chorizon
Jack manning wrote:Not to horn in, but I have an ac unit in my tear and I use a 10" muffin fan ( the kind used in electrical panels)mounted in the side wall to vent the heated air from the condenser. It consumes .23 amp and moves 640 cfm.I have pic's in my galley. Hoped this helps
Jack manning


I'm a little embarassed to say this, but I bought a 10" tubaxial fan for a machine the other day and the cheapest I could find it for was $215. I assume you paid nowhere near that considering a Fantastic-Fan is half that. Where did you find your fan?

exhaust fan

PostPosted: Thu Mar 25, 2010 7:44 am
by Jack manning
ww grainger has a wide assortment of neat little axial fans,I believe I paid around $60.00. This was a couple two years ago.
Jack

PostPosted: Thu Mar 25, 2010 2:43 pm
by Bilko1448
Not sure if this helps anyone but look here> https://www.surpluscenter.com/sort.asp? ... yword=EBFA They have a bunch of different sizes and in ac and dc.

PostPosted: Thu Mar 25, 2010 4:23 pm
by RichAFix
Not to horn in, but I have an ac unit in my tear and I use a 10" muffin fan ( the kind used in electrical panels)mounted in the side wall to vent the heated air from the condenser. It consumes .23 amp and moves 640 cfm.I have pic's in my galley. Hoped this helps


Aren't these little "muffin" fans kind of loud? I am looking for peoples experience with what kind of fan is the quietest. Is a squirrel cage blower a little quieter? Thoughts?

exhaust fan

PostPosted: Thu Mar 25, 2010 4:56 pm
by Jack manning
It would depend on where and how it's mounted. Mine is in a compatrment that is isolated from the main cabin, it make noise outside but is not heard over the ac unit inside.