For any one that is going to install roof top ducted air . I have a tip and how to , That may help, go to Coach Conversion Central , It is on the first page. http://users.cwnet.com/~thall/ It may help. Fred
Great pictures, Fred. The rounded corners should make all the difference in the world.
I guess I'm not holding my mouth right-went to the site and saw nothing about ducted air conditioning. Maybe a better clue? Good Luck, TomC
Quote from: TomC on August 29, 2007, 08:39:47 AM
I guess I'm not holding my mouth right-went to the site and saw nothing about ducted air conditioning. Maybe a better clue? Good Luck, TomC
Tom, Here is the direct link to Fred's tips:
http://users.cwnet.com/~thall/fredhobe.htm
Richard
Hi Fred,
Great metal work! It takes quite a bit of thought to do it right.. Huh..
It really stinks to put all that effort into the metal work and have to cover it all up with ugly duct tape and foam/plywood..
Good Luck
Nick-
Hi
That takes a lot of great deal of skill to do that kind of work with metal - Nice JOB
I was fortunate enough to great a grand tour of Featherlite Vantare and Millennium Coach here in Florida
They both used this product for ALL their duct work--> ULTRA DUCT http://www.insul.net/prod_ultraduct.html
Vantare order a number of 4 x 8 sheets for me - ULTRA DUCT would have cut the sheets down and shipped them to me - but Vantare orders them in huge quantities and ships them in as 4 x 8
they are only 1/4 thick - super easy to work with - just cut it with a razor blade - score the bend lines and fold up and tape.
rounded corners were no trouble at all -
Super light weight / no rattle / no sheets metal / no screws/ it's insulated material - so much less sweating
It worked great for me - simple - cost effective - don't remember the cost per sheet - sorry - just call ULTRA DUCT.
Pete RTS/Dayton
As much as I'd love to duct my Carrier heat pump, I don't think that would work on an MC-8 without a raised roof. Has anybody been able to do this without raising the roof or dropping the ceiling. Maybe I could make some low profile ductwork on top of the roof, insulated, of course, and accomplish the same thing! ;) J/K
David
Quote from: DavidInWilmNC on August 29, 2007, 11:02:26 AM
As much as I'd love to duct my Carrier heat pump, I don't think that would work on an MC-8 without a raised roof. Has anybody been able to do this without raising the roof or dropping the ceiling. Maybe I could make some low profile ductwork on top of the roof, insulated, of course, and accomplish the same thing! ;) J/K
David
Hi David,
I think it depends on "how tall you are" Lol
Nick-
Quote from: RTS/Daytona on August 29, 2007, 10:21:52 AM
Hi
That takes a lot of great deal of skill to do that kind of work with metal - Nice JOB
I was fortunate enough to great a grand tour of Featherlite Vantare and Millennium Coach here in Florida
They both used this product for ALL their duct work--> ULTRA DUCT http://www.insul.net/prod_ultraduct.html
Vantare order a number of 4 x 8 sheets for me - ULTRA DUCT would have cut the sheets down and shipped them to me - but Vantare orders them in huge quantities and ships them in as 4 x 8
they are only 1/4 thick - super easy to work with - just cut it with a razor blade - score the bend lines and fold up and tape.
rounded corners were no trouble at all -
Super light weight / no rattle / no sheets metal / no screws/ it's insulated material - so much less sweating
It worked great for me - simple - cost effective - don't remember the cost per sheet - sorry - just call ULTRA DUCT.
Pete RTS/Dayton
Hi Pete,
In our trade, we call that stuff "Duct Board".
I did three install with the stuff 12 years ago and everyone of them bit me because the paper/foil tape failed
that holds the seams and ends together. Many times we were called back to reseal the joints with more tape.
It also may just be the environment they are installed in too. Like attics, and crawl spaces. excessive heat and moisture.
I have stuck with metal ever since. There is nothing like mechanical fasteners...
Good Luck
Nick-
Foil faced ductboard works fine with foil tape (we used to staple it also), but that was for attic/chase supply/return line installation (flex duct for branch lines) - foil tape has no shear strength and can be a problem where there is movement or vibration - the belt and suspenders installation in a bus would be- duct mastic on lap joint, then foil tape, staple through foil tape/lap joint, cover all with continuous wrap of regular duct tape - JMO
Nick
I used 3m - 2 mil Alum Foil tape on all the joints - worked great - can't get the stuff off with a sledge hammer ??
The product looked/felt like cellophane wrapping tape with a shinny silver/alum finish - got it at Lowes
Nothing ever loosened ?/
Pete RTS/Daytona
Hi Pete,
We use the foil tape here too but, on FBBF [foil, bubble, bubble, foil] insulation stuck to metal duct only.
On duct board it's marginal at the least. Like Jim has stated, the shear stregnth is not there.
And my 6mil costs $21 dollars a roll. It's not uncommon for a job we do to exceed $150 just in alum tape.
I just hate it when we go back to a previous install for tune-ups, and find ton's of boxes stored on our duct work.
Most of the time, I even find my metal ducts cruched from homeowners storeing things like "Wehght sets" on the trunk?? ??
If I can't build it to last a lifetime, then I just won't build it at all... That's how old school I am, I guess! Lol...
Nick-
I have to agree with Nick on this, with all of the vibration and possible movement, metal duct is the only way, with plently of fasteners, Nick do you have any pictures of your duct when your bus was being converted? Fred did a really nice job with his duct work, especially making the curved transitions to direct the flow smoothly!
Pat
Fred,
Very nice work on the ducting! Just wanted to say your advice here is very much appreciated. Please post more of your ideas, everyone could benefit from them. I don't think anyone on this board would slap you for soliciting your ideas and work! You are a benefit to all of us!
Happy Trails,
Paul
Dreamscape
I was thinking of using ULTRA DUCT but might change now after reading this post. Thanks to all for there advice.
Is there any noise from the metal duct with the movement of the bus?
I was thinking of putting ALTRA DUCT on top of plywood with a wide metal strap shaped like a hat channel over the seams.
Fred always gets a good topic going.
Paul
www.incredibus.com
Nice job. My next bus or motorhome will have a high enough ceiling to have a drop to facilitate ducting. Am toying with the idea of using a Freightliner truck and making my own box-possibly a 26ft box that would facilitate a car inside and still be under 35ft overall. Good Luck, TomC
Nick do you have any pictures of your duct when your bus was being converted?
Hi Pat,
Yes, here are a couple..
Nick-
Nick- nice job! You'd think from the pictures that you were a professional at air conditioning. LOLO. Good Luck, TomC
Nick, what type of insulation did you use for your ducts? How thick is it? Is it directly against the roof, or is there additional insulation between the roof and the duct?
Although my ceiling's not high enough for ducts in the center, there is hope! When I installed my unit, I didn't cut the main beam but instead mounted to the side. I've been thinking that if I used a ducted air box / return and ran the ducts to the side of the bus along the windows, I could achieve close to the same thing. I'd have to fabricate a surface 'box' that would be finished the same as the ceiling to take the place of the current free-blowing section that's there now. This would have to connect to the side ducts on the ceiling (or slightly recessed), but this is over the sofa and won't be in the way. The free-blowing part does hang down about 2.5", so I wouldn't lose any additional head room. The side ducts could easily be integrated into a valance above the windows. The vents would be mounted onto this valance. My MC-8 still has the drop in the ceiling over the driver and steps. If I mounted the front unit close enough, I should be able to run the ducts for the driver and passenger in the is space and still have a couple runs to the side channels. My OTR air still works, so that's not a prime concern at this point, but it could be in the future. At any rate, the bus needs more than one A/C unit up front to cool it off when it's been sitting in the sun. Have others run any surface ducts along the ceiling or walls?
David
Thanks Tom,
Hi David,
I lined the entire ceiling of my bus with tek foil [fbbf], then constructed my main trunk in a "U" shape with 1"
flanges to attatch it to the ceiling. Then wrapped the trunk with 1 layer of FBBF. The trunk is 2 1/2" X 14".
Here is a link to simular as to what I use.
http://www.teksupply.com/farm/supplies/prod1;ts1_tekfoil_reflective_foil_insulation;956af1a4_100760.html
David, You plan sounds like it will work. Just give good thought as to where you place your supply grills.
Good Luck
Nick-
the way I used the ULTR-DUCT is different then it would be used in a house
I have 2 x 4's running the length of my RTS BUS (remember RTS's have 6'8" ceilings THE FRAME RIBS) on both sides forming a "H" channel 3.5" deep x 10" wide - I then scored and folded and taped the ULTRA-DUCT to fit in that channel and used following bends to eliminate any sharp Right angle bends
The ULTRA-DUCT is supported on both sides by the 2 x 4's and on top by my first layer of 3/4" inch insulation board R-MAX foam used to bring the roof level with the RTS's ribs - the bottom is supported by the RV ceiling - That leaves 3.5" of layered insulation board R-MAX for the rest of the roof. Plus that addition 3/4" foam to fill to the frame ribs + 3/4" foam in the roof dimples
I got so much insulation in my RTS - it's like driving in a THERMOS BOTTLE
The ULTRA-DUCT seams are taped but - where the hell are they going to go if the tape loosen (which it hasn't)
Pete RTS/Daytona
Just the way I did it - am I'm very very pleased with it
The way FEATHER-LITE and MILLENIUM did it was to simply lay the boxed / taped ULTRA-DUCT ducts on top of the ceiling truss in their MILLION DALLOR Prevosts - I believed they used straps and wire ties to prevent them from moving around.
We used the UltraDuct in our bus. We happened to be near Lowell, Indiana and picked up the 4x8 sheets at their facilty (They will cut the sheets into 2'x4' pieces for shipping by UPS). They took us on a tour through their plant and also showed us how they pre-assemble duct components for the major S&S builders in the area. Ours has been in since '99 and no signs of failure. We did follow their instructions to the letter when building and installing the ducts. Jack