Over the road A/C

[TomC]

As reflected in some of the recent posts, some are keeping the over the road A/C system.  These are typically 10 ton units (a roof top unit is one ton) that are sized to keep 45 heat producing people cool.  While they are gigantic systems that can double as a refrigerator, the cost to keep them running, the cost of fuel from the compressor drag and fan drive, the extra space they take up that could be used for other things, I don't know why they are kept in.  Not saying my way is right, but as example, I have a 40 x 102 transit with many large windows with just a light tint.  I have 3 roof airs that usually 2 will do the job with 3 needed when in over 100 degree weather.  Instead of powering a big belt drivin compressor that takes around 25hp with a fan that takes another 10hp, I'm powering the roof tops that essentially take about 2hp each to run.  Granted you have to run your generator while going down the road, but remember these gen sets are made to be run for 10s of thousands of hours (I have a truck driver friend that just got rid of there truck with a PowerTech 7.5 compact lay down with a 3 cylinder Kubota that had over 23,000hrs on it without engine overhaul!).  And on top of this, in the 12 years that my three roof tops and generator have been in, I have had zero problems with them.  I bet you can't say that about your over the road A/C!  And if I do have a problem, just pull one off and put a new one on for about $600 and about 2 hours worth of work.  Good Luck, TomC

[Nick Badame Refrig/ACC]

Hi Tom,

To Each His Own.... with respect of course!

I kept my road air because it's needed while traveling in 90 + temps. Even in extreme temps like this, I only have to cycle the road air

maybe twice an hour for 5 to 10 min, then leave the blower running to circulate air. Works very well...

That is why a normal automobile's air condtioning system is sized from 4 to 5 tons. Way larger than your roof tops can deliver while in motion.

You need that capacity for quick cool downs when your vehicle is sitting in the sun, or even if you stop to do some shopping. A roof top will take hours to bring the

temps back to normal, where the road air will take 5 to 10 min.

Nick Badame-

[TomC]

Nick- I can appreciate you using the over the road since you can keep the system in top condition for the price of wholesale parts. But most of us don't even know where to take these units to have them worked on.
Just a comment on temp draw down.  I came back to the bus after an outing where it had gotton unseasonably hot.  The inside of the bus was at least 90 (the thermostat was pegged).  I fired up the gen and started all three A/C's and in 30 minutes was down to a comfortable dehumified 80 degrees with it being down to where the A/C's started to cycle at 72 (where I have them set) within an hour. Granted, if you have just one roof top, it won't do it.  Just relating personal experience.  Good Luck, TomC

[DrivingMissLazy]

Nick, how do you keep it operating while shopping? I assume you do not leave the DD ideling? Just run the blowers?
Richard

Hi Tom,

To Each His Own.... with respect of course!

I kept my road air because it's needed while traveling in 90 + temps. Even in extreme temps like this, I only have to cycle the road air

maybe twice an hour for 5 to 10 min, then leave the blower running to circulate air. Works very well...

That is why a normal automobile's air condtioning system is sized from 4 to 5 tons. Way larger than your roof tops can deliver while in motion.

You need that capacity for quick cool downs when your vehicle is sitting in the sun, or even if you stop to do some shopping. A roof top will take hours to bring the

temps back to normal, where the road air will take 5 to 10 min.

Nick Badame-

[ceieio]

I wish my bus air worked!  I only have two roof airs and need to add something else to cool it off when going down the road.  Most of the bus air parts and pieces are still in there, but I think they need to be replaced (fins seem brittle on the condenser? in the side for example).  I guess I will add another air somewhere (near the driver please!) and call it a day.

Craig - MC7 Oregon

[Nick Badame Refrig/ACC]

Richard,

You wrote:
Nick, how do you keep it operating while shopping? I assume you do not leave the DD ideling? Just run the blowers?
Richard


You misunderstood me, I'm talking about recovery time after you shut down and go shopping for a while.
Nick-

[DrivingMissLazy]

Now I understand. Thanks, Nick.
Richard

Richard,

You wrote:
Nick, how do you keep it operating while shopping? I assume you do not leave the DD ideling? Just run the blowers?
Richard


You misunderstood me, I'm talking about recovery time after you shut down and go shopping for a while.
Nick-

[Ednj]

Yesterday, I let my over the road A/C run while refueling, Thats how long it took to freeze up.
I still don,t have enough return and supply, but it works.

[Nick Badame Refrig/ACC]

Ed,

Look's like your trip is going well. That's great!

Hope to se ya in Delawere..

Nick-

[Ednj]

Yes Nick I will be in Delaware.
Check your e-mail.

[Beatenbo]

Nick is right. Every need is different. I drive 30-35 K a year and a good bus air is a plus for me. Sure a worn out system can eat your lunch  I've gone as much as 2 years at a time with out even adding freon on other buses. I have had about 3 major brands roof airs and never thought they were adiquate. I have had bus air that would drop inside temp 20-25 degrees from outside. I have never seen roof airs frost the windows during the day. Some people rip out all heat and air before conversion. I hate to thnk of no good old bus heat in Jan and Feb. My compessor is bad and I'm replacing this week I can't wait to get my bus air back running.
Again every need is different. As the old saying "what ever floats your boat, or what ever cranks your motor !! " I'll take bus air any day/ I love hearing my wife say, "it's cold in here."

[Hobe]

With 4 inches of foam in the roof and the inside skin isolated from the the outside ribs. And 2 inches in the side walls. I can run ome roof top in 90 plus weather. And two in Airizona in 100 plus. How your roof tops work is in direct relations to how good your insulation is in your coach. At $3 a gallon for fuil I would reather run a gen set at about 1/2 gal. a hour than the coach motor pulling that 25 ton air . Just my idea of 20 plus years of travel. Fred

[novice]

Nick, is the temp the main reason you prefer the bus air while traveling?  We have three CruiseAir's and since our bus air is not working at the moment, we ran the generator and had all 3 CruiseAir's on, which seemed to cool the bus quite nicely.  If temp is not a factor, do you have any other reason for not wanting to run your generator all day plus the bus engine?  If running the bus air subtracts 2 miles a gallon,  (I'm not sure of the exact mileage numbers we may be talking about, but thought 4 MGH to 6 MPG).at 60 MPH that uses 5 gallons more fuel  in one hour.  If the generator uses 1/2 or maybe 3/4 per hour, it seems the better way to go.  Am I missing some part of the puzzle?

[Nick Badame Refrig/ACC]

novice,

I'll say it again, To Each His Own..   Nothing but personal prefrence.

I like the coach air, Thats me!   You may be different!  Thats you!    That also apply's to anything about your bus.

I'll repeat my reasons that are stated above, I like to cool the coach from 95+ to 70 in 5 to 10 min. thats it! Then I shut it down...

I also use my gen set and Cruiseairs if I have a half hour to wait for them to catch up. If not, I fire up the coach air.

Nick-

[novice]

Thanks Nick, didn't mean to sound picky, just wanted to be sure I understood.