Factory AC Retrofit!

[dbsoundman]

Hi all, I happened upon a fellow in Virginia on Facebook that was giving away the factory AC system from his 05(?) Thomas bus. While it was a dognose bus, it had the same Cat C7 engine as my FE transit bus, so I said "I'll take it!". A friend of mine has picked up all the parts and I'll get them from him in June.

The plan at this point is to install probably just one compressor and one exchanger inside near the front. I have been told that the complete system is coming to me: two compressors, all the inside exchangers, and who knows what else. I'm sure it's not sealed up so I'll have to replace or blow out the lines somehow. I have not done a lot of research into AC systems at this point but I did flare my own mini split fittings so I guess I'm not a total n00b . I'm not sure about the compressor bracket either, I'm hoping that's included but if not that may be the one "big expense" of this system other than refrigerant.

Any tips, reading material/references, or thoughts would be appreciated.

[cadillackid]

ive done quite a few retrofits of exactly what you are doing.. I also own a lot of the tools to make the lines and crimp the fittings.. no flares required, they are all O-ring fittings.. the compressor brackets are the hardest part.. often different from an RE bus to a dognose CE style.. FE style often matches a dognose when it comes to engine accesories but sometimes (like in the case of cummins) the compressors have to go on the bottom for clearance in an FE.. many different bracket sets are still available.. just have to see what you get..

there are also different types of A/C line as well.. some A/C companies used standard large diameter barrier hose with crimps (looks like your car) and others used reduced diameter barrier hose with Clip-style fittings (what I use on new installs)..



O-rings are standard size and you always change them.. flush the oil out of each piece you will use and install new.



vacuuming down the system accounts for moisture that accumulates while its been open.. it just stays on the vacuum pump a long time..



its hard to get vehicle A/C any lower than 1000 Microns as the compressor seal isnt designed for negative pressure and will oftentimes leak with a vacuum but not with pressure.

[dbsoundman]

Thanks Cadillac, I'll definitely be posting more once I get the system in my hands. I'm picking it up in early June. We're thinking of putting in just one passenger unit and maybe try to get dash AC working too.

[cadillackid]

if you are doing a good job insulating your bus then you can get away with one system unless you plan to fill the bus with people and want the whole thing cool front to back..



if you use a Sanden SD7 Enhanced compressor (not a cheap imitation).. you can get quite a lot of capacity out of it.. I have 2 evaporators in my DEV bus on the one compressor.. a 50K mid unit and a 20k dash unit.. thats pushing the limits of the compressor but it still blows cold esp out on the road.. im using a CS3 ACT 3 fan 80k condenser.. and im using envirosafe 134A replacement refrigerant which is most surely better capacity than 134a..



for a dash unit you want bigger than you think.. I put that 20K dash unit in the dev bus and thats only really good because i have the mid unit too which helps with the load.. the windshield and engine load in a bus is high.. in a conventional the footwell gets hot despite dynamat and reflective insulation on the doghouse and firewall area.. so I have a vent that blows some cool air into the footwell..



I used a 36K BTU under-dash unit in my Superior.. it looks like a retro Jeep A/C except its triple the capacity of a standard car under-dash unit.. has 2 motors and 4 blower-wheels and 6 vents.. in that nbus its the only A/C as mounting dual compressors on an air-brake, power steering gas motor is near impossible.. just no room and belt pulleys.. so I hang a shower curtain up behind the first row of seats and it keeps me nice n cool up front.. im using an IH York 210 compressor (for nostalgia purposes) and its over-worked by that heavy duty evaporator..