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Author Topic: Over The Road Air Conditioning  (Read 4309 times)
TomC
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« Reply #15 on: February 03, 2008, 11:22:37 AM »

The nice thing about Red Dot is the many different configurations you can get.  With the marginal cooling on most buses, I would highly recommend using a remote mounted condenser with a built in 12v fan.  Personally I would think there would be enough unused space up front near or under the drivers seat that the condenser could be mounted there. Then all that would be added to the engine would be the belt driven compressor.  Red Dot makes the A/C systems for Freightliner, Peterbilt, Kenworth and others-so they are both tested and reliable.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
JohnEd
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« Reply #16 on: February 03, 2008, 02:05:13 PM »

I think air infiltration is the real FIRST ISSUE.  Insulate all you want and get as big an air conditioner unit as you wish, but leave a window open and you are going to be at ambient.  The frontal area of the bus has to be hermetically sealed and all the front has to be air tight cause that is a high pressure area and you let a really efficient flow of air into the bus with a comparitivly smallish hole up there.

Just sitting with the heat on I'll bet it is easy to keep toasty warm....even with holes in the front,  so that isn't proof of good sealing.


Good hunting.

John
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Jerry Liebler
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« Reply #17 on: February 03, 2008, 05:01:51 PM »

Fredward,
      You have way to many air leaks causing huge heat gain while driving. Things like door seals, window seals, unplugged old ducts etc.   I use a single 18,000 BTU/h ductless minisplit and can maintain 72 inside while driving 65mph on a sunny 95 degree day.  On a similar day parked in the sun it was 70 in the bus.
Your results are about what I was getting with 2 'portable' heat pumps rated at 10, 000 BTU/h.  The portables were simply fraudulently rated and really weren't delivering even 5,000 BTU/h . 
Regards
Jerry 4107 1120 

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Fredward
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« Reply #18 on: February 03, 2008, 06:52:26 PM »

Jerry,
I think that is my problem. The RV windows are cheap and they rattle when I drive which means they must leak. I don't know that I have any major leaks in the front, but obviously there is a lot of hot air coming in somewhere. I've considered replacing the new windows with higher quality new windows. I still like the idea of putting a Red Dot or similar supplemental AC because then i wouldn't need to run the generator as much. We have a 2K inverter which will handle anything else necessary while driving down the road.
Fred
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Fred Thomson
TomC
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« Reply #19 on: February 03, 2008, 09:38:19 PM »

Fred- the power to run the A/C has to come from somewhere-whether it be running the generator, having a belt driven compressor on the engine, or extra drag on the engine alternator running the A/C through the inverter.  Personally, just stay with the roof tops running the generator (it's what I have and like it) then you won't have the extra A/C system to contend with and the 35 ft of freon lines from the engine to the front of the bus.
Whether it be a 5hp draw on the big engine, 5hp draw to run two roof top airs, the amount of fuel burned is nearly the same to create the needed power for the air conditioning no matter what's powering it. Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #20 on: February 03, 2008, 10:30:19 PM »

So how much do these Red Dot units cost on average?

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Lin
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« Reply #21 on: February 03, 2008, 11:52:50 PM »

In my opinion, a separate engine driven bus A/C is the first class way to go.  If I bought a coach that had it, I would attempt to keep it going.  That is one reason I have considered a Wanderlodge in the past.  That stated, since the coach I have does not have one, I would stick with the roof airs.  For the front unit to really work for the driver, it would have to be as far forward as possible although I have seen a rooftop unit ducted to the front.  I suppose this could even be a for-the-road-only removable duct or some sort of booster fan could be included to get the air where you need it.  Our first regular motorhome had dash air but, since we lived in the desert, we found it best to curtain off the front of the cabin anyway.  Unless one has unlimited resources, it's always a matter of prioritizing time and money.  A new dash air system would not be at the top of my list.
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donnreeves
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« Reply #22 on: February 04, 2008, 04:40:43 AM »

If I were to buy another bus, I would give serious thought to keeping the over the road air and heat. That said, the system I have in my RTS is very comfortable. There are two Carrier 13,500 btu ducted roof airs with ceiling vents located where we need them. there are four vents up front that keep it cool. Last summer we drove for several hours with an oat of 98* with the sun comming in my side window, and it was still very comfy with the air on low speed.On High it freezes us out. Granted I have a lot less interior volume than a lot of you, but a properly designed roof air system will work fine, provided there is good insulation.  Donn
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makemineatwostroke
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« Reply #23 on: February 04, 2008, 07:32:06 AM »

Guys, if its so easy to cool these buses with 1 or 2 units why does it take 5 or 6 units with over the road air to keep the converted Prevosts cool that are foamed at the factory.     just asking
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H3Jim
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« Reply #24 on: February 04, 2008, 07:41:02 AM »

Maybe size or glass area.  I have 3 rooftop airs and I like to be cool.  When my over the road air developed problems on a trip last year, the rooftops didn't come close to keeping me as cold as I like.
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Jim Stewart
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DavidInWilmNC
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« Reply #25 on: February 04, 2008, 08:37:11 AM »

I also like to be cool ... some would call it cold... when I drive.  The 76° mentioned in an earlier post, although at very extreme outside temps, wouldn't be cool enough for me.  Our humidity sucks, too.  I'd like it closer to 70°.   The heat radiating off the windshield and driver's window is also pretty intense.  I'm thinking that some of the factory 'conversions' have so many units (5) is because they're often painted black or some other dark color on the roof and that it takes 3 units to keep it cool throughout the bus normally, 4 to cool the back area, and the fifth one for when one's trying to cool the bus down initially or if one of the other units fails.

David
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luvrbus
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« Reply #26 on: February 04, 2008, 09:43:50 AM »

Last year I purchased a Red Dot system like Jim has with a remote mount condenser I haven't installed it yet because of all the work so I am thinking about selling it and going with the 110 unit from Proair or Dan Hard that way the inverter or generator ( if I need the crusie air to help) can supply the power on the road or I can use a power pole at RV camp ground.I know it won't have the BTU as the Red Dot but I won't have the 40 ft of hose and freon to worry about
« Last Edit: February 04, 2008, 09:49:02 AM by luvrbus » Logged
steamguy56
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« Reply #27 on: February 04, 2008, 09:49:17 AM »

Removing the o/t/r for space in this area, the bus was equiped with helper system in the back, this removed. I would like to use it up front.
                         Danny
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TrevorH
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« Reply #28 on: February 04, 2008, 04:36:14 PM »

What could one sell a complete working OTR air system for? (102a3)  I think this would have alot to do with whether one would keep in it and deal with the extra maintnence or look elsewhere...
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Stan
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« Reply #29 on: February 04, 2008, 05:10:42 PM »

Many years ago, I sold a good compressor and condenser for $1000.00 and I don't expect their value has gone down. Those are the two components that get frequent replacement, while the rest of the components probably have not much resale value. Give them to the buyer of the compressor and condenser as a bonus if he gives you a good price.
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