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Specialists within a specialty industry

By Elvis L. Hoffpauir, MACS president and COO
We know that MACS members are the best of the best, the crème de la crème, go-to guys even for other A/C service shops when those shops need help on a really tough job. And we generally think of our members working on cabin climate control for passenger cars and light trucks, maybe limos and some buses.
But there’s another whole world out there, off the road, far from the beaten path, where monsters dwell. In this case, I’m talking about everything from monster machines that prowl farmland, construction sites, mines, quarries and battlefields, to an almost endless variety of smaller but no less exotic equipment, all with A/C installed to cool the human operators.
Within our own cadre of repair and installation specialists there is an elite group whose focus is at least partially, if not completely, on this type of equipment. We polled some of them and asked for a sampling of what their past projects have entailed.
One of our friends, and MACS’ unofficial dean of HD and off-road A/C, was quick to respond with photos from a site he’d been at the day we contacted him. The subjects were draglines used in lime rock mines, each weighing about 600,000 pounds; the operators are cooled by RV units installed in the cabs. The photo portfolio also included a mobile drilling platform and a track mobile, designed to move railcars.

Another member located near a military installation recalls a Humvee configured with a pop-up, climate-controlled enclosure to serve as a mini-field hospital or temporary shelter against biological or chemical attack. The same member had a mobile rocket launcher in his shop.
Some special mobile equipment is technically for use on the road (or at least near it), but machines in this category are still very different from the small vessels that transport the family to the baseball game or carry Johnny to his Taekwondo class.
Consider what might be in the stable of a Dept. of Transportation (DOT): snow plows mounted on class-8 dump trucks or John Deere tractors, vehicles that paint stripes on highways with as many as three separate climate controlled operator cabs, and lawn mowers with HVAC in the cabs.
Ambulances often begin with a basic OEM cab-and-chassis using a factory installed HVAC system. A specialty-body builder adds a second system, and sometimes more than one, with multiple additional evaporators and multiple fan-cooled condensers. In addition to this, many units are required to have a separate refrigerated cabinet for medication.
If you are on a long trip on an interstate highway, you’d think the ubiquitous 18-wheeler must surely outnumber family sedans and SUVs. Likewise, there are myriad configurations for the heavy-duty work truck.
And sometimes it’s not just operators, drivers or passengers who have to be kept cool. One MACS member reports a custom A/C install for a client-made cool box used to haul lobsters from Maine into the heartland. Another job was adding an A/C unit to a truck cap to keep produce cool. The same shop owner recalls fabricating many A/C lines for systems whose owners had installed used parts from other vehicles in their hot rods, trucks and campers.
Those who turn their skills to these types of jobs must be masters of innovation, who can figure out a way to overcome design flaws or unfortunate use and environmental conflicts to make A/C systems work even when they’re not supposed to – kind of like making bumblebees fly.
Unfortunately, not all of these exotic applications can be made to work. Another member, now enjoying his retirement, recalls “a long time ago (the mid 1960s) in a shop far away, I was involved in the attempt to air condition an aluminum crust breaker. In the electric aluminum smelting process an oxide crust would build up between the anodes. One company built an air operated vehicle with a jack hammer to break the crust. The intense heat and electrical field made an air operated system the only practical way to remove the crust. The operator could spend approximately 15 minutes breaking crust before being overcome by the heat.
”So the task was to drive the compressor with an air motor and fan to cool the condenser and use the exhaust from the motor to blow across the evaporator and cool the operator. Needless to say it didn’t work but it was a great idea.”
Have you worked on any exotic vehicles? Drop me a line and a photo.
When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.

If you’re a service professional and not a MACS member yet, you should be, click here for more information.

You can E-mail us at or visit to find a Mobile Air Conditioning Society member repair shop in your area. Visit to find out more about your car’s mobile A/C and engine cooling system.
The 32nd annual Mobile Air Conditioning Society (MACS) Worldwide Convention and Trade Show will take place January 18-20, 2012 at the Rio All Suite Hotel and Casino in Las Vegas, NV.

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