Red Dot Air Conditioning on a 712K - install and pics

[Slappo]

Hey all,

So, a few of you were interested in seeing the air conditioning install I was planning. It's now finished and operational. I ended up getting a Red Dot R-9777, which is a newer slimmer model. The case is made from high strength plastic, and it's basically unbreakable. It's also very easily serviceable, since the case is held together with clips that pop open, instead of screws. Let me first start off by saying that I couldn't have done this myself, so I hired ThermoKing Intermountain in Salt Lake City. They do roof air cons for trucks/tractors/trailers, but had never done a Pinz, and really were excited about the project. Troy Evans is the parts/service manager there, and he did such a spectacular job overseeing the project - he really went the extra mile on everything, including custom fabricating the compressor mount and the roof bulkhead mount. If anyone is in UT, or close by, and wants to do this kind of project, I can't say enough good things about these guys. It's worth the extra expense, and now that they have Pinz experience, they'll do even better next time.

Here are the pics:

https://picasaweb.google.com/1104883622 ... directlink

A few things to note:

The interior vents of the unit are not centered on the unit itself, so, you have to decide whether the interior vents will be centered (making the unit offset on the roof), or whether the unit will be centered and the interior vents be offset. I opted for the latter, since there are roof rails on this truck, and didn't want to try to raise the unit to clear one side. You can't really tell in the interior that the vents are offset, so not a big deal.

Since this is a K, the roof had an antenna mount on top that had later been converted to mount for a large emergency light. This light was removed, leaving just a raised mounting plate. We decided that because the location of the unit was going to be as close to the cab as possible without interfering with the hatch, we'd use that existing hole to put the refrigeration lines and power, so we didn't have to punch any more holes in the roof than was necessary. It actually worked out quite elegantly. Since the front of the unit near the fan is cambered, that camber allowed Troy to craft an angled bulkhead mount with fixed fittings that the lines could mount to, preventing the need for sealed grommets. It also makes for easier repair to the lines if necessary.

So, as you can see in the pics, the compressor lines go through the dog house (behind the passenger seat), up the side wall, and across the roof of the cab to the angled bulkhead mount. They then snake around to the rear of the unit, without any need to create additional breaches in the roof. Power is routed to the drivers side cab wall, running along the bottom of the door frame, and connected to the battery, as well as connected to one of the fuses.

The unit has two drains and we decided that rather than let the water just drain on the roof, we'd make a small hole in the roof behind the driver's side passenger door, and run a drain line down into the wheel well. This was also done with bulkhead mounts rather than grommets, to eliminate the potential for cut lines, or the need to reseal often. It also makes for easier repair of the lines.

Power draw: There is a little bit of a power drain, but not too much. If you turn it on while idling, you can definitely notice the power draw, but at highway speeds, you don't really notice at all. This truck has a stock engine and so really doesn't have much highway power anyway. Going up inclines did slow me down a little with the air con on. Semis on the highway under loads were passing me. I'd turn the unit off to test it, and while there was a slight gain in power, it wasn't enough to completely change the speed up a significant incline anyway. I'm planning on upgrading the engine here soon to 2.7 and give it a new ignition system to make up for that slight power loss.

Pulley: to operate the compressor, you need a double or triple pulley. With the triple pulley, you have to shave a little off the engine block (this per Jim LaGuardia), otherwise the pulley won't seat properly and bolt won't tighten. There's also a little nub that has to be shaved down as well. If I find the link on the forum for that little tidbit, i'll update the post. Also, when using the triple pulley, the fan should use the outside channel, the air con should use the middle channel, and the inside channel should be free for any add-on (like EFI/fuel injection).

I drove with it a few hundred miles in the hot Utah desert (96 degree weather), and while it doesn't get the cab "cold" necessarily, it makes it relatively pleasant in the cab. A 712 is a lot of truck to cool off at that temperature, but it did a great job, and with the air blowing on you directly in the cab, you don't really notice. I didn't take the temperature, but I'll bet it was somewhere around mid-70s in the cab. If you're alone in the cab, it helps a lot if you close off the other vents and drop the curtain.

Since the vent had to be installed at the bulkhead, we removed the center divider cage. This allows easy positioning of the vents, as well as easy access to the control panel, even from the cab. You have to reach under and find the knobs blind, but once you get used to it, everything is easy to locate.

Out the door, it was $4300 total. $1500 for the unit, $500 for the triple pulley (SwissArmyVehicles.com), $500 for additional parts, and $1600 for the labor and the rest was tax. Expensive, indeed, but the quality of the work was definitely worth it to me. Will be much cheaper obviously if you DIY (which I wouldn't have been able to do).

That's it!

[Profpinz]

I'd be interested to have a look at the pics but unfortunately the link is not working....could you check it....thanks!
I'm "playing" with ideas of fitting an integrated system into the Pinny (albeit a TD) so there is no rooftop unit, but I'd still be interested to have a look at your setup.

[Slappo]

Fixed.

[David Dunn]

Very nice. Now you need tinted glass to reflect some of the heat and glare.

[Slappo]

I'm actually going to pull the tinted K-door windows and rear pane off my MK that you did, for precisely that purpose. =)

[djw]

Thanks for posting this detail. The roof dimensions of the unit look larger than I initially imagined. Really nice 712K.

[Slappo]

Added some more "in progress" photos.

[djw]

You're a star!

http://www.rdac.com/resources/blog/putting-ac-pinzgauer

[Profpinz]

G'Day Slappo, I just wondered how the Red Dot was performing?

Given the high temperatures we've had of late, the fact that the weather bureau have said we can expext increased numbers of hot days in the coming years and as the 718 rebuild is progressing well, ones thought turn to its future use and cool travelling.

I'm still considering an integrated unit for the 718, but I've also researched a number of rooftop units, however I like the R9777 for its size, reported durability and aesthetic functional form which matches the Pinny design.

Your thoughts would be appreciated!