Over the road A/C

Buffalo SpaceShip · July 24, 2006, 09:25:55 AM

Usually, the older the coach chassis, the more maint. that goes into coach A/C and chasing down leaks and freon. An old 4104/06 with R-12 and 40+ year-old compressor... fuhgetaboutit! A newer MC9 or 102 with R-22 and modern compressor... keep it.

Personally, I'd love to have ten tons of A/C when I needed it, but the decision to remove mine was made long before I purchased my '78 4108 conversion... and it was probably the right decision, once maint. became too overwhelming.

Every coach, conversion, and converter is different.
Brian Brown
Longmont, CO

Beatenbo · July 24, 2006, 06:35:01 PM

I am not a know it all, but I have never noticed a big difference in fuel mileage running my bus air. Every MCI I've owned seems to average around 7 mpg air or not. I've only got 8 mpg once You couln't convince me it would make 2-3 miles per gal difference cruising on the interstate. I can see the difference running my gen constanly.

Bosshosssport96 · July 27, 2006, 09:34:00 PM

Couple of questons...........If the compressor in a roof top air conditioner is a 1 ton,and a automobile is a 4 to 5 ton,what tonage compressor is in a 14/15 mini bus that has an carrier air system?

When compressors go bad,are they repairable,or is it just cheaper just to go out and buy a new one.?

Haven't been able to find a junk yard to remove such a system here in San Diego nor anywhere in Calif ( I'm sure their here,just can't find one)

FloridaCliff · July 28, 2006, 06:25:42 AM

Boss,

I have seen the ones your talking about.

I think they are a standard roof top unit that is supplementing the factory air conditioning.

Cliff

Bosshosssport96 · July 28, 2006, 07:15:25 AM

The ones that I'm thinking about are are the ones that have the ceiling mounted evaporator in them,with maybe the condenser being under the body.I think its a Carrier Transit Cold system....Frank

FloridaCliff · July 28, 2006, 07:27:35 AM

Frank,

Gotcha,

I would be interested in what you find out or other know on those also.

Cliff

Gary W · July 28, 2006, 10:29:32 AM

Nick I have a question for you , you said you cycle your over the road air for a few minutes then just leave the blower on to circulate the air. Did you install a swith to cut the compressor in and out? I have a 1986 MCI 102-A 3 and the way I read the wiring diagram the air conditioning compressor runs all the time when when the A/C switch is on, adding heat to the coach when it gets to cold.

Gary

H3Jim · July 28, 2006, 11:29:52 AM

I really hate being hot, and that bus air is really great to have. My bus is a 1995, and although I have had to charge it once in 2 1/2 years, its a small price to pay for that air that works so well. The rooftop is nice, but is nowhere near the capacity of the bus air. Unless it starts $1,000 me to death, I plan on keeping it for a long time. Driving at 65 or 75, seems to require more cool air than just sitting, and with those big windows I have...

NO way am I pulling that bus air out, I'm with you Nick

Bosshosssport96 · July 28, 2006, 02:58:59 PM

Ok Nick.where are you brother...........*smiling*....time to answer some questions that a few of us have for you............Frank

TomC · July 28, 2006, 03:24:47 PM

The Carrier transcold units typically use "car" type compressors. One of the favorites is the A-6 compressor which is the old GM design 6 cylinder with wabble plate. It puts out 12.6 cu in, up to 6500rpm on 12v or 24v, and 60,000btu max. On our Thomas buses, they'll use two of these to power one A/C in the front and back. As compared, the big Carrier compressor for buses is 37cu in output. Because those large compressors cost $1,250 exchange rebuilt compared to a Sanden car type (that you could also run two of them for almost the same power output) compressor is about $350 new with new clutch. Just thought you'd like to know. Good Luck,TomC

Bosshosssport96 · July 28, 2006, 04:19:45 PM

Thanks a lot Tom.....Frank

Nick Badame Refrig/ACC · July 28, 2006, 06:08:17 PM

Quote from: Gary W on July 28, 2006, 10:29:32 AM
Nick I have a question for you , you said you cycle your over the road air for a few minutes then just leave the blower on to circulate the air. Did you install a swith to cut the compressor in and out? I have a 1986 MCI 102-A 3 and the way I read the wiring diagram the air conditioning compressor runs all the time when when the A/C switch is on, adding heat to the coach when it gets to cold.

Gary

Gary,
Yes, I cycle the blower with the A/C / Heat Switch. I do that by having the heat valves closed off. The blower will still cycle when the switch

is in the heat position. I will flip the switch up to A/C for a few min's, than flip it down to heat to only circulate cool air.

Frank,
I think Tom C answered most of your questions. But, you should still be able to find thoose Carrier TransitCold systems in some salvage yards!

Good Luck Guy's
Nick Badame

Nick Badame Refrig/ACC · July 28, 2006, 06:15:05 PM

Quote from: Bosshosssport96 on July 28, 2006, 02:58:59 PM
Ok Nick.where are you brother...........*smiling*....time to answer some questions that a few of us have for you............Frank

Frank,

The temp was 99 today, so even I had to take on some service calls. I think the 5 of us did 31 jobs today...

And just so you guy's know, There is 12,000 btu's in a ton. And 9,000 btu's in a horse power! And I'm sure all of you

Know ... BTU's = British Thermo Uits! And if I remember correctly, An average person gives off 1,000 Btu's of heat per hour..

Nick-

TomC · August 02, 2006, 10:18:18 PM

I think you meant British Thermal Units. Just like it is youths, not youts. Good Luck, TomC

Nick Badame Refrig/ACC · August 03, 2006, 03:54:42 AM

Hey Thom,

Da ya knw whre eye caan fid a goud spl cker?

Nik-