Orton DIY - Maxxair Fan Install

[Graphite Dave]

I chose the Maxxair 6200K fan for two reasons. It was designed so it can be open while driving and it can be open in the rain. I did several things that I thought would improve the installation. I made a 3/4" plywood backing plate picture frame to install inside to reinforce the opening and I made 1/8" x 1" aluminum plates to distribute the load at the bolt heads. The RV places said the plastic frame will crack at the bolt holes so I added the aluminum strips. I also did not want to use the SS sheet metal screws supplied and instead used through bolts with an elastic stop nut.

Procedure:
1. Made a 14" x 14" plywood template with a 5/16" hole in the center and four 1/8" holes in the four corners. The 1/8" holes were 7/16" in from edge of pattern. I used a 7/8" dia. electrical knockout to get nice rounded corners in the 14" hole.
2. Drilled a 1/8" hole through the roof where I wanted center of opening. Enlarged that to 5/16". Bolted plywood template to the roof. Rotated template as required to make opening square with the Sprinter cross ribs. Tightened center bolt. Used duct tape to hold template in place.
3. Drilled four 1/8" holes in corners using template holes as guide. Removed template.
4. Enlarged four corner holes in roof to 3/8" for knockout stud. Punched the four corner holes.
5. Drew a line tangent to 7/8" dia. holes to mark saw path. Cut between each corner hole with jigsaw from inside the van. Wish I had some clear goggles to keep metal out of my eyes.
Cut 3 sides of opening and then added duct tape on top and under roof on the three cut sides to keep 14" sq. plate from falling when I made the last cut. Removed any Mercedes sound deadening material that was in the way.
6. Put plastic fan ring into opening and held it centered with duct tape.
7. Went back on top and drilled the four corner bolt holes. Bolted ring down at the four corners. Drilled remaining holes by using the plastic holes in the ring as a guide.
8. Removed ring and cleaned up and painted edges.
9. Added butyl tape under flange and added aluminum strips over plastic flanges. So sandwich was 1/8" alum.,plastic fan flange,Sprinter roof, 3/4" plywood backing plate.
10. Trimmed off extruded butyl tape that was pushed out and then caulked the edges and the top of the bolt heads.

 

[Oldfartt]

Hi Dave,

Excellent rightup.
I have the same fan but have yet to receive the van! Maybe it will arrive soon. I will copy your install and use the extra alloy plates too. Do you intend to paint the alloy plates?

Cheers

Ross

 

[Graphite Dave]

Will not paint the anodized aluminum. I have had anodized 80/20 on the bed flanges of my 2003 Dodge Dakota for 8 years and they look fine. If you bought a 144" WB van the magic number from centerline of second rib from back is 10 1/2" (centerline of second rib to centeline of 14" opening). The plywood frame will be against the flange of the second rib from the back and plastic fan ring will just miss center corrugation toward back. Attached is a PDF drawing of what I did. Should make it easy for you.

 

[Oldfartt]

Ok thanks for the info. I did not realize that the flanges were anodized. That should be fine. Mine is an extra long (170) but I can still use the information. Gee I wish I had your cad package.

Cheers

Ross

 

[Graphite Dave]

Cad package: go to generalcadd.com and download free software so you can try it out. Free trial package is complete except you can not save drawings. If you like it buy it for $599.00. Nice easy to use program that is less costly and much easier to use than Autocad.

 

[Geek]

thanks for this Dave

I'm hoping to get a chance to install mine tomorrow.

 

[mattwiz]

Dave,
Thanks for all your write ups, they have been very helpful. I have a question...
I have a 170wb and wanted to put my fan toward the back where it would be over the bed, however that would require me to cut thru one of the ribs in the roof. When you did your install you had to flatten one of your ribs, right? Is this a bad idea to mount it here? How did you flatten your rib out? I was thinking of using a vice up there and squeezing it down. Thoughts?
Thanks. Matt

 

[Thanasis]

Dave,
Thanks for all your write ups, they have been very helpful. I have a question...
I have a 170wb and wanted to put my fan toward the back where it would be over the bed, however that would require me to cut thru one of the ribs in the roof. When you did your install you had to flatten one of your ribs, right? Is this a bad idea to mount it here? How did you flatten your rib out? I was thinking of using a vice up there and squeezing it down. Thoughts?
Thanks. Matt

I think you can find a method for installing a fan toward the back here:
http://www.steynfamily.com/ultimate_windsurfing_van_02.htm


Thanasis

 

[Graphite Dave]

Need to be sure we are talking about the same thing. I did not touch a rib that supports the roof. The ribs are perpendicular to the length of the van and protrude down into van under the roof. I did flatten the end of the center stiffening corrugation (one of 7) that is parallel to the length of the van. I had to do that because I did not follow my own drawings. As I recall it was only about 1/2" at the end of the corrugation. I did not flatten a full height corrugation. Just the end of it. I do not think I would try to flatten a full height rib. The other 3 sides of my opening were flat. The steel is very soft and easy to flatten with a hammer from above and a steel block held under the steel. Be sure to prime and paint the damage. I assume you do not have a flat spot without corrugations in the area you want to put it. Maybe someone else has installed a fan where a corrugation is located and could enlighten us on how they did it. FYI I just leave the Maxxair partially open all the time. With the hole in the floor open I do not need to use the fan because I get the chimney effect of hot air rising.

 

[atulin]

Dave,
Thanks for all your write ups, they have been very helpful. I have a question...
I have a 170wb and wanted to put my fan toward the back where it would be over the bed, however that would require me to cut thru one of the ribs in the roof. When you did your install you had to flatten one of your ribs, right? Is this a bad idea to mount it here? How did you flatten your rib out? I was thinking of using a vice up there and squeezing it down. Thoughts?
Thanks. Matt

I think this a 170 vs 144 issue difference.

I'm trying to decide how to put the maxxair in the back of my 170 right now. Flattening out the ribs on the roof seems possible but it would still not be completely flat. There is an area near the back that looks like it would allow the fan to site flat on the roof without flattening any ribs but I would need to cut out a section of the roof support. I'm thinking about doing that and taking thin wall square steel tube and making a square that would bridge the section that is cut out and give the fan something to mount to.

 

[Charlie]

Atulin,

If by "cutting out a section of the roof support" you mean the side to side cross members, I would advise against it. You would be messing with the structural integrity of the roof. I'm not saying it couldn't be done, but it would be a lot of work to solve a minor problem with the small ribs (corrugations in Dave's post).

I installed a rear MaxxAir over one rib and found it quite simple. Cut your standard opening, then cut a notch in the metal where the rib is to allow the top flange to fit. The notch should be no deeper than needed to fit the flange. A hacksaw blade in a plastic handle is a great tool for this job. Because of the raised rib, you can start the cut without drilling any starter holes.

Next frame the inside with whatever wood you like. Make sure the wood under the rib is an inch or so wider than the MaxxAir flange. There will be a gap of about a half inch between the rib top and the framing. You could tap the rib down a bit to reduce the gap, but don't try to close it. Paint the bare edge, install the flange and fill the gap with whatever you are using as a sealant (I used butyl rubber). By filling the gap from the inside, you can be sure it is fully filled. The sheet metal gap under the flange due to the notch is only 1/16 and just gets filled with sealant when the flange is installed. You could put in a filler shim but it is not really needed.

I'm on my second winter in western Oregon with no leaks.

Charlie

 

[mattwiz]

Charlie,
That is a pretty good idea. I was thinking about a shim under everything to make it all the same level as the top of the rib, but your way would work too. Not sure which path I will take yet, but I will get some pictures when I do. Thanks.

 

[OrioN]

My fan is installed over the roof corrugations. I make a curb, which the fan rests on, out of 1" styrofoam. I was able to carve out the corrugations and sand out the left/right roof curvature.
I made it 3/16" narrower than the base, so that I was able to have a 1/4" thick bead of sealant. Took all of 15 minutes to 'carve'.

 

[mattwiz]

Aren't you all pretty smart. I like the ideas here. However, the wife said put it here so it doesn't blow in my face when I am sleeping and the place she pointed has a break in the corrugations so I will get a flat surface to mount on after all.

 

[Graphite Dave]

One thing I have learned is to leave the vent partially open all the time. I do not close it unless I am sleeping in it and it is cold outside. I also have a hole I cut in the floor that is also open all the time unless sleeping when it is cold. The combination acts like a chimney with cool air from under van flowing out the Maxxair vent because hot air rises. Works great and most of the time keeps van at outside temperature. Summer will probably require turning on the fan. My installation allows me to reach the fan controls and the hole in the floor vent cover when I am in bed. The low floor opening and high vent opening copies what I did when I built my barn and house. I get air flow without running a fan.

 

[mattwiz]

Dave, your hole was about 4"x4" right? I saw it a few times can can't recall. I have been thinking about that same idea as well. Just trying to balance out road noise and the chance of exhaust getting back in for location.

 

[OrioN]

Aren't you all pretty smart. I like the ideas here. However, the wife said put it here so it doesn't blow in my face when I am sleeping and the place she pointed has a break in the corrugations so I will get a flat surface to mount on after all.

Flat is as roof is curved, but alas, it's only about 3/32" per side and could/should be shimmed.
Also, the higher the curb, the more space you get below to stuff an insulated fan 'pillow' for when you are winter camping.


PS... a nice place for a mechanical louvered "OrioN Hole" (of which Dave keeps forgetting to accredit, as he's under a lot of stress these days) is on the vertical wall just above the sliding door step.



.

 

[Graphite Dave]

The hole is 3.5 x 4.5 and is located in front of the left rear wheel. I have not noticed road noise or exhaust fumes. Exhaust is on opposite side.
orion: I have not seen a posting with the famous hole. Please direct me to it. In fact I have not seen your write up on your conversion. All I know is it weighs too much. After Sprinterfest I will weigh mine to see if I made the same mistake. I will ignor the stress comment due to it being unappropriate.

 

[Graphite Dave]

The Maxxair fan will rattle if vent is partially open while driving. Quiet at closed and full open when locked. The rattle comes from the pins on each side of the lifting mechanism in the metal slot attached to the plastic cover. Sent email to Maxxair suggesting a change to plastic to metal interface. They responded that they have redesigned the parts and added a nylon bushing to solve the problem. Today I received the parts at no charge. They added nylon bushings to the arm pins and redesigned the metal angles that are bolted to the cover so they accept the new bushings. Should solve the problem. I would guess the new fans have the revision.

 

[Graphite Dave]

The kit consists of two new larger slot metal angle brackets that replace the existing ones that are screwed to the Lexan cover and two nylon flanged bushings to be put on the pins. Takes about 20 minutes to make the change.