Trans Air in 1990 Blue Bird All American

[Other Animal]

My partner recently bought a 1990 Blue Bird All American transit bus, which has a Trans Air air conditioning system. When we try to turn them on the P/S (I'm assuming pressure?) light on the rocker switches comes on while the fans underneath the rear of the bus, and the units themselves do not.

Both of us are inexperienced when it comes to these systems, but fairly mechanically capable. Ultimately I have a few questions:

• Are the trans air systems in the rear of the bus worth keeping (knowing they are run by the bus's engine)?
• How common are leaks and is this what causing the light to come on?
• Is it possible to keep just one?
• How complicated is the removal process?
• Is it possible to get them to run off of shore power in addition to the motor?
• Is there a common go to for air conditioning with skoolie conversions?

 

[Twigg-SKO]

My partner recently bought a 1990 Blue Bird All American transit bus, which has a Trans Air air conditioning system. When we try to turn them on the P/S (I'm assuming pressure?) light on the rocker switches comes on while the fans underneath the rear of the bus, and the units themselves do not.

Both of us are inexperienced when it comes to these systems, but fairly mechanically capable. Ultimately I have a few questions:

• Are the trans air systems in the rear of the bus worth keeping (knowing they are run by the bus's engine)?
• How common are leaks and is this what causing the light to come on?
• Is it possible to keep just one?
• How complicated is the removal process?
• Is it possible to get them to run off of shore power in addition to the motor?
• Is there a common go to for air conditioning with skoolie conversions?

It would seem that most people remove installed AC systems for a number of reasons.

They often don't work. HVAC work is expensive, and many school districts don't do it. PArts, when you can get them, cost a fortune.

They only cool when the engine is running. They are rated to cool a tin can rolling along in 100+ temperatures, so they are costing quite a bit in diesel to run them.

They take up a large amount of space that can be put to better use.

When you have stripped and insulated the bus you have a much smaller cooling requirement, and a two-zone mini-split can do that job whether moving or on shore-power.

You generally can't use AC while boon-docking, unless you have enormous battery storage and a solar array costing thousands. An inverter generator would work, and be much cheaper and quieter.

If you buy a SPED bus the chances are you will have extra work removing the AC, but fewer seats to remove. Activity buses designed for highway use will probably have it too ... but again, most folk would remove it.

 

[PNW_Steve]

When I converted my first bus I ripped the road air out thinking that the 2x 12,500btu roof air conditioners that I was going to install would keep me cool while driving.

I was wrong!

I would surely recommend that you give serious consideration to keeping them.

 

[cadillackid]

if you plan todrive your bus in much warm weather you keep the transAir units.. or at least one of them (in the front) if you have 2.. yes the PS light is low pressure.. it has a freon leak.. 1990 means it likely still was running R12 and someone likely coneverted it to 134a and it leaked out.. or perhaps it was never converted..

I myself personally ADDED engine driven A/C to one of my busses so I wouldnt sweat on the highway.. if you dont mind being hot in the summer driving then you can take the system out without hurting anything.. if you dont like being hot then its worth finding the freon leak, converting it to 134A and keeping it...

-Christopher

 

[Rivetboy]

Trans airquestions

Hi, go to the Trans air site and you can sign up. This gives you access and you can see whats available. They are a simple system , at least the one in my 91 TC 2000 is and parts are not to bad and with part numbers you can substitute like for like.If you pop off the filter inside by the control board there is usually a schematic. Any reefer mech with a set of gauges and a vac pump can work on them. They actually sell a combo at Harbor Freight for under $200.00.
A lot of times just refilling the system with the proper refrigerant after evacuating it will bring it back to life.

 

[golfersmurf57]

I will say this about the transair units. They get super cold when they're working right. I'm not sure but the fans for the condenser are probably powered when the compressor clutch turns on. If the compressor isn't running probably no Freon in the system usually takes about 30 psi on the low or Suction side to enable them.
When I'm charging on only the low side, I usually jumper out the low side pressure switch to make the compressor run if you have twins one compressor for each side.

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[golfersmurf57]

I agree with PNW steve
Why run the genny while driving? If you're going to pull them usually the side mounts run the lines straight up the center of the condenser fan units with an access cover on the inside the drip tube from the evaporator is usually run there as well.

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