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Air conditioning

Just rode in a rental car company shuttle van that was ice cold from a carrier unit on the rear ceiling.  No generator just the van motor. Why at this point do most MH still have a car's dash air for cooling while driving?  This seems insane.  I have a friend with a mid 70's GMC MH where previous owner installed a remote evaporator and condenser amidship powered from the stock compressor.  He is able to comfortably drive without roof air. Would someone explain the woefully designed MH cooling systems?  It is like having a fully modern kitchen with every gadget yet still has an ice box instead of a refrigerator. I just don't get it. Why aren't scaled down bus air units standard in every MH?  The whole roof air / generator thing is crazy considering the size of the main powerplant.
Dwayne Keith
1992 U240
3116/MD3060

Re: Air conditioning

Reply #1 –
We're in Tucson and the school buses that we've seen have four roof top units.  I was wondering how they were powered.  Surely they don't have an on board generator. 
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George Hatfield

  Never ever use World Line Motors of Nacogdoches for service!

Re: Air conditioning

Reply #2 –
My guess on the school bus, it would have a generator, and as for Dwayne, I would guess it comes down to cost.  Having had a MCI ex Greyhound bus, yes it did have a 9 ton compressor, and 300 amp @ 28 VDC alternator, (Read that as 600 amp at 14 volt), massive everything. Know our little boxes require much less, but I would guess the cost would be prohibitive vs just run the little genset.

The genset would use less fuel than the main engine to do the same job to run the added equipment.

Example, 2 A/C units running on genset would draw approx. 26 amp @ 120 volt if the compressor ran 24/7.  That is less than 1/3 of the capability of a 10 kw genset. In real life that would require about .4 gal diesel fuel per hour, Where would the cost effectiveness be adding a massive a/c unit, while you still need the genset when  you stop.
THIS IS only my guess.  It is good subject to talk over.

Re: Air conditioning

Reply #3 –
Quote from: Dave M –
The genset would use less fuel than the main engine to do the same job to run the added equipment.

I asked the same question - and that was the answer I got.

Of all the different coaches I checked out, I'd have to say 95%+ had nonfunctional dash air. My U225 was no different. Given the engine is in the back, and the condenser in the front, that it leaks with 70 odd feet of hose is no surprise. The dealer told me everyone he knew ran the genset and the roof airs to stay cool while driving. It was more cost effective than running the engine powered A/C (mileage goes south).

I looked at bus conversions long and hard in searching for a coach. Most of the ones I saw had the bus A/C systems removed and replaced with roof air units. Supposedly more efficient.

Steve
1991 U225 Grand Villa

Re: Air conditioning

Reply #4 –
Mine works - does a great job of freezing my knees. We run the gen on the road, both roof airs and the reefer on AC. Takes about .5 gph. I run the dash air in recirc, compressor off to circ the cold air from behind me.
The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT

Re: Air conditioning

Reply #5 –
Like Dave H, my dash air is very fine and cold. As I mostly travel alone, the dash air is plenty and has never had any issues YET. The best part, I finally figured out how to live with the condinsation on windshield, DO NOT use defroster, I turn the A/C up max, max fan and it seems to work so far.  Would like to have the A/C compressor some on when turned to defrost.  It is not that way now.
Before I figured out the a/c bit, I used a window squeege on long stick to swipe across to get a peep hole. Was more exciting than needed to be. :o

Re: Air conditioning

Reply #6 –
A few years ago Dometic and Coleman(now AirXcel) came out with basement units and I think they are still making them.  Everything was in one box, so all that had to be connected was the wiring and air ducts. Winnebago and some others were installing them for awhile, not sure if they still are.  The MH has to be designed to accept the unit, and have the ductwork for air distribution.  Some storage space is lost, but the installation is quieter than roof air.  They may not have cooled as well as roof units, but at the same time almost all the RV manufacturers switched to dark paint schemes making cooling more difficult, so that may be part of the problem. 

I have been toying with this idea for a 96 U270.  Buy a couple of new high quality 15K btu high efficiency window units (or possibly one 15k and one 12k), have the refrigerant removed, saw the units in half (probably voids the warranty) so that the condenser, compressor, and fan motor are still one unit.  Basically we are just removing the evaporator, its fan and the controls.  Install the control units inside the coach in a suitable location/s.  Build an air handler to contain both evaporators and a fan/s to fit in the space above the washer/dryer. An extra fan motor/s and fan/s will have to be purchased for the air handler. The air handler should have a pan to catch the condensate and drain down to the condensers for evaporation.  Install a drop ceiling similar to the 97 and later models for air distribution.  The 2 condenser units are to be mounted next to the engine on the left side.  The standard muffler will have to be removed and replaced with the smaller aero muffler and the dash air condenser relocated.  Install a grill in the fiberglass panel same as on the right side for the engine radiator.  My engine air cleaner is located athwartship at the rear, so I don't have to contend with that.  The condenser units are to be mounted in a metal frame with isolation mounts.  The condenser side faces the engine and compressor is outboard.  Air flow is toward the engine and is directed upward so it flows out the rear door.  Install refrigerate lines and wiring and recharge with refrigerant.  One or both units can be used as needed to cool the entire coach or part of the coach.  Both units operate on 120v 20 amp circuits and draw less than 15 amps each even with the addition of another fan motor.  (My older 13.5k btu units pull about 15 amps each.)  Remove the roof units and install a skylight, or close and insulate the opening.  I suspect that on the highway in hot weather, heat off the road might reduce efficiency to less than that of roof units, but when parked the units are shaded improving efficiency.  Noise in the bedroom should not be any worse than the roof air, maybe even less with good isolation mounts.

If someone would give this a try and let me know how it works out, it would be much appreciated.
Jerry Whiteaker former owner 96 U270  36' #4831 Austin,TX-Owner Mods LCD TV w/front cabinet rebuild - LCD TV bedroom - Dual Central AC, either can cool coach w 30 amp - Skylights at roof AC openings - Drop ceiling for ducting of AC - Shower skylight white gelcoat/wood/epoxy frame - Air Springs/Shocks replaced - 2014 CRV - 8K Home Solar - Chevy Volt

Re: Air conditioning

Reply #7 –
Jerry, Before you saw an AC in half talk with any Winnebago owner who has basement air.  I know of none who are happy and many who are pi..... In fact Winnebago has ceased to use basement air in new coaches.
Good luck

Re: Air conditioning

Reply #8 –
Quote from: Merle Hench –
Quote from: Dave M –
The genset would use less fuel than the main engine to do the same job to run the added equipment.

I asked the same question - and that was the answer I got.

Of all the different coaches I checked out, I'd have to say 95%+ had nonfunctional dash air. My U225 was no different. Given the engine is in the back, and the condenser in the front, that it leaks with 70 odd feet of hose is no surprise. The dealer told me everyone he knew ran the genset and the roof airs to stay cool while driving. It was more cost effective than running the engine powered A/C (mileage goes south).

I looked at bus conversions long and hard in searching for a coach. Most of the ones I saw had the bus A/C systems removed and replaced with roof air units. Supposedly more efficient.

Steve

Bus air and roof AC units are different things in bus conversions. I looked extensively at them just this year. The bus air is what you run going down the road. You lose a compartment and can not be placed on quad slide coaches.  On one or two slides you can have bus air. It runs off the main engine and it is what they used to keep busses cool with passengers. You can hang meat in them with it on full bore. Then there is the aux generator that runs off the main engine to run the Roof ACs or the basement mounted ones. There is some difference in opinion but the Liberty guys still put a huge unit in the basement and it does keep the height down a bit that way too.  Then you have roof ac units. You can have roof units and bus air in fact if I was to get a bus I would have bus air from prevost and either roof or basement unit for my AC unit. I have no opinion. Kind of like the roof version so I get more storage but that is about it.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Air conditioning

Reply #9 –
Gary,

This is probably way in the future if ever.  Don't know which unit Winnebago used, but the largest Dometic basement unit is 27k and if a heat pump 26k.  Coleman is only 24k according to their literature.  27k is what my coach came with.  Add in slide outs with increased volume to cool,  increased surface area for heat intrusion, and dark paint for more heat gain, easy to understand why there is a problem with not enough cooling and PO'd owners.  30k btu would be the absolute max, but surprising that they didn't make the units larger to start with. 
Jerry Whiteaker former owner 96 U270  36' #4831 Austin,TX-Owner Mods LCD TV w/front cabinet rebuild - LCD TV bedroom - Dual Central AC, either can cool coach w 30 amp - Skylights at roof AC openings - Drop ceiling for ducting of AC - Shower skylight white gelcoat/wood/epoxy frame - Air Springs/Shocks replaced - 2014 CRV - 8K Home Solar - Chevy Volt

Re: Air conditioning

Reply #10 –
I was talking with our own Barry and he shot the side of his green coach and it was much hotter than my white coach.  I also have 3 AC units. Two 15K BTU and one 13K unit that is still the original. THe three really work to cool the down pretty fast in pretty hot weather.  I have only had 2 before and the third is something I will always have.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Air conditioning

Reply #11 –
Jerry, you have certainly given this a lot of thought.  I remembered something that might work.  I have a 63 Falcon Sprint convertible and I was looking at adding A/C.  On this car the heater box is inside under the dash on the passenger side.  Classic Auto Air makes a "looks original" A/C unit with everything except the compressor inside a duplicate heater box with all the pre-cut lines to tie the two together.  Something along these lines might be adaptable for MH applications.  They sell nationwide but are based here in Tampa.  I might stop by and chat with them soon or look them up at the Turkey Rod Run in Daytona or the Winterfest in Zephyrhills next November...they are usually there.
Dwayne Keith
1992 U240
3116/MD3060

Re: Air conditioning

Reply #12 –
When I worked at Country Coach (briefly) I learned of the system they put on the Rhapsody.  Installed on the C15 engine was a 500 amp, 24 volt, water cooled monster alternator.  This was so they would have full A/C without using the generator.  This was a feature the marketing dept deemed necessary.  However, in 2008, CC discontinued rear (bedroom) A/C (it was a 2nd evaporator running of the engine compressor) in the Magna/Affinity models.  Surveys of customers found that most didn't even know they had it, let alone used it. Most passengers ride up front where the dash is.

IMO the reason you don't see full coach road air is because it a duplicate system that will have little use and take up precious cargo room.  It's a must to have roof (or basement) system for when your parked and a must to have the generator.  You might as well use them for road air too.  The situation is very different for a passenger bus where you need air for the whole vehicle,  the main engine is running all the time, and they usually have extra space in the basement.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Air conditioning

Reply #13 –
Like Jerry I've thought about additional A/C from a standard window unit: 
In a Grandvilla, if you remove the TV that's under the dash for a swing down flat screen mounted to the ceiling you can use the old TV space for mounting a 3rd A/C.  No mods to the window A/C would be necessary.  Just cut a rectangular hole in the forward bulkhead and use that like you would mounting it into a window.  Some re-arranging of componets mounting to the outside of the bulkhead would be required.  The exterior airflow would be hampered by the front cap but an automatic mechanism to crack open the the two service hatches below the windshield would improve that considerably.  One downside is that since this would be a permanent installation, most window A/C's are terrible about keeping cold out when winter comes.  An additional insulated cover/box on the inside would be good.  I have no idea how this would work on bus style front end coach - may be not enough room.  I think about this less since moving to a more northern climate.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho
 

Re: Air conditioning

Reply #14 –
If you search There, I Fixed It - Redneck Repairs, you should be able to find examples of household window units applied to vehicles. I doubt that you would want to follow the examples in application to your Foretravel, but tastes differ. The site has many "interesting" solutions to problems one might encounter in a "house on wheels."
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX