Orton DIY - Maxxair Fan Install

Midwestdrifter

Engineer In Residence
Replying to myself, you can get replacement parts here in Oz through various retail/online outlets. I used Caravans Plus. It came to $44 shipped. I emailed Maxxair initially and they sell it for USD$13 but then would charge shipping, making it near enough local prices. It was helpful in that they gave me the actual part number so I could search locally 10-20281K-1af. (The online parts manual doesn't give proper replacement part numbers from what I could see)


Ah, the Oz "tax" which is basically just retailers sticking it to consumers due to monopolistic market control.

Never fear, Amazon is here! :thumbup:

I found that the support at Maxxfan was pretty good when I had a rattle issue.
 
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TaoOfWoo

Member
I have 2 factory fixed glass sunroofs and would like to know what everyone’s thoughts are on the best place to install a maxxair fan 7500. The factory sunroofs are in the flat spots that would be the ideal candidates for fan install. I think most people prefer a fan in the rear so that if you crack a front window there is cross flow. I can’t get pics to upload, but I have 15” behind the rear crossmember to rear of van. I have 21” between crossmembers just aft of the cab. I can’t take one of the factory sunroofs out because the hole would be too big for the maxxair. They are approx 17”x35”.
https://sprinter-source.com/forum/album.php?albumid=704&pictureid=4432
 
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peeela

New member
Below is the offset adapter we CNC'd for our Transit. We've produced a number of these for Sprinters as well.




Brilliant. I’m about to hand make my own adapter from Ekodeck bamboo/polyurethane, but it’s going to be a lot of work to get the slight curve to match the sprinter roof.

What is the material you use?

Would you take an order for 2 x offset-from-centre, maxxair fan offset adapters? And 2 x hollandia 100 offset adapters? Both for Sprinter 144/MWB.



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peeela

New member
I have 2 factory fixed glass sunroofs and would like to know what everyone’s thoughts are on the best place to install a maxxair fan 7500. The factory sunroofs are in the flat spots that would be the ideal candidates for fan install.

I hear your pain. Configuring a roof layout is quite a challenge. To achieve the van I really want, I’m taking the [probably] unavisable route, and placing the rear combo of fan and sunroof where the last roof cross member “used to be”. I’m rebracing around the sunroof and fan to reinforce to the sides, and to the rear, and forward crossbeam.

1. Good solar panel clearance
2. View of the stars from bed :)
3. 450W solar
4. 2x Hollandia 100
5. 2x Maxxair Maxxfan Deluxe





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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.
I may have missed it, but what are the diameter of the holes on the aluminum strips? I didn't see them on your drawing?! I don't have my fan yet (coming Monday) and am having a friend cut the aluminum for me this weekend!

Thanks Dave!
 

Graphite Dave

Dave Orton
I may have missed it, but what are the diameter of the holes on the aluminum strips? I didn't see them on your drawing?! I don't have my fan yet (coming Monday) and am having a friend cut the aluminum for me this weekend!

Thanks Dave!
You did not miss it. Not on the drawing. Added the dimension. Used 10-24 through screws which are 3/16" diameter so holes were 3/16"
 

splitfuse

New member
Thank you for everyone's contribution. Interesting thread as I have been mulling over fan sealant systems for my Maxxair 7500k installation. Based on obsessive research, at a minimum I would suggest a two pronged approach:

1) Apply a quality butyl tape between van and fan flange - this is your last line of defense should there be a breach in the primary sealant. Butyl also allows for easy future removal should it be needed in 10-20+yrs.
2) Apply the primary sealant (lap sealant; Sikaflex 521UV for example) to the fan flange screws as well as sealing the transition from flange to van around the perimeter of the fan.

3) For the OCD types :rad:, keep item 2) to a minimum with nice clean beads (even use masking tape and tool the sealant around perimeter) and then add a third layer of protection: 3M extreme sealing tape or EternaBond Roof Seal min of 2" wide (3" is probably ideal) over the fan flange and onto the van around the perimeter of the fan.

I like the idea of Dave's alum reinf but would definitely be applying sealant between the alum and fan. Part of me is concerned with this second lap joint as a potential leak point although a 3 pronged approach would ease my concerns.

Important:
- Ensure compatibility of all products with the acrylic fan housing; the instructions have a long list of specific incompatibilities. On this topic, still waiting to here back from EternaBond
- A bit of Scotchbrite prep on van and acrylic sealant bond areas and either IPA or product specific primer ensures a top shelf, long lasting bond
- Watch product min service temps if your from the great white north. Some 3M products don't have readily published minimum service temps and Dicor has yet to send me their product datasheets. Personally I'm striving for -40oC as a min and would prefer a -50oC since -40oC is not uncommon in my neck of the woods.
 

GSWatson

2013 144
Here’s a my installation schedule -

- bead of exterior sealing caulk at internal corner of fan mount
- butyl tape
- another bead of caulk at edge of fan mount

- Tape area around for a clean bead

- 1/8” aluminum bat on top of flange mount

- caulk in screw holes

Afterwards, the roof (to seams, not visible from the street) is painted with elastomeric roof sealant, two coats. This also goes over the aluminum bar and screws on the fan mount.

As a lifelong sailor and former boatbuilder, I’m confident of no leaks. I recently dropped the ceiling of my van and there was no indication of any leaks. I also use MDO plywood to build up the internal spacer; it’s what used to be used for road signs. Very durable stuff.

That being said, I have no idea if this would hold up in your extreme temps...


Cheers,
Greg
 

FMMM

Member
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.
What size of bolts did you use to bolt the fan on - I'm DIY illiterate - M5/length?
Thanks
 

Graphite Dave

Dave Orton
Thanks
Did the bolts just slide through [the plastic flange] or did they need to be screwed through?
Apologies I'm DIY illiterates!
Bolts slide through the flange holes. It is important to add a 1/8" x 1" aluminum flatbar under the bolt heads to distribute the load so plastic flange does not crack. I had a RV shop tell me that the plastic flange will crack at the bolts, so I added the aluminum flatbar.

The install instructions say to use sheet metal screws but I used through bolts with a wood picture frame under the roof. Bolts so through the aluminum flatbar, the plastic flange and then the wood picture frame.

Did not have the plastic frame crack after 5 years on either the Sprinter or Transit build.
 

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