'91 TC2000 road AC

[dalez]

So another major component of this conversion I'm eyeballing trying to figure out - the engine driven AC. Having one is a practical requirement for me in the south. It currently has a nonfunctional TransAir system. Transair couldnt find any documentation on it. I started tracing the lines, and what I found is the system is comprised of two AC compressors in parallel, two condensers at the very rear, occupying both valuable underbody bays and also appearing to be plumbed in parallel together, one HUGE and entirely dead seeming evap over the rear window taking up valuable space, and tee'd off the lines running aft from the engine is a MUCH smaller evap right over the driver's head.

From a practical standpoint, I dont need the rear evap as long as the front can cool the area from teh windshield to about 6ft behind the driver, maybe even less area if I really needed to curtain the AC off into a smaller space to make it work for me. It's in the way of one of very very few places to put the minisplit evap later. The two condensers both are taking up highly valuable space underneath the rear, and this bus has very very little underbody space considering I need a larger fuel tank, a gray water tank, a generator, a spare tire, and somewhere for the minisplit condenser.

So for those with lots of AC experience... what do you think? I dont see capacity numbers on anything, so we're all just guessing. Could I eliminate one compressor, one condenser, the huge rear evap, and just one one compressor to that small driver's evap? Is that driver's evap gonna have enough capacity to cool more than just the driver? Is it even enough for that by itself? Will the system need modification to work properly with the half the condenser and compressor, but only a much smaller fraction of evap left? Maybe build another small evap for up front? Thoughts?

[ewo1]

Don't eliminate anything!

Me rear unit was inop and it turned out to be the circuit breaker tripped in the control panel. It tripped I believe because 1) it had a major leak and 2) just recently the compressor itself smoked!

I just replaced both compressors and will be doing a vacuum and charge later in the week.

You may be mentally justifying only having one a/c unit but believe me, when parked in the sun on a Texas hot day, you will need both units!

Resources:

https://donbrownbusparts.com/collections/trans-air-ac

http://www.valeocompressors.com/

https://www.transairmfg.com/bus-air-...-documents.cfm

[dalez]

When parked the 12kbtu mini split will be at work, while driving I'm really only concerned with the driver's area and a few feet back for a passenger or two and plan to curtain off the rest. At this point I'm intending to pull the ceiling and build up insulation and thermal breaks on the ceiling and on the metal panelling of the walls, and thick insulated curtains for the windows, and the top of the roof will be covered in white silicone. Two 5kbtu window units were enough in my old 36ft bus that was poorly insulated, I would think a 12kbtu should be enough while stationary in this shorter one... But while driving I need cold or my autoimmune condition flares and causes serious issues.

[ewo1]

Originally Posted by dalez

When parked the 12kbtu mini split will be at work, while driving I'm really only concerned with the driver's area and a few feet back for a passenger or two and plan to curtain off the rest. At this point I'm intending to pull the ceiling and build up insulation and thermal breaks on the ceiling and on the metal panelling of the walls, and thick insulated curtains for the windows, and the top of the roof will be covered in white silicone. Two 5kbtu window units were enough in my old 36ft bus that was poorly insulated, I would think a 12kbtu should be enough while stationary in this shorter one... But while driving I need cold or my autoimmune condition flares and causes serious issues.

All that sounds good and dandy but have you really looked at the unit to determine if it is an easy fix or if the unit is toast?

In the end it is all your choice/decision. I fixed both my units and yes will still be installing a minisplit for when I am long term parked.

IMO, window unit are ugly, unprofessional and reflects one took shortcuts!

[dalez]

Agreed on the window units, that's why I'm not putting those on the new bus. I dont care for roof top units either, and I want the heat pump functionality common to mini splits anyways.

I havent dug very deep into why the system isnt working. The way they put it together it's hard to even get gauges on it. The blower motor on the front evap comes on, but barely spins and likely needs the bearings replaced, and that's the only sign of life I've seen out of any of it. If I dont eliminate the rear evap, I'm likely to have to go with a *ducted* mini split to make it fit, and the ducted ones only come in 240v which means installing a transformer too.

FWIW, I spun the compressors by hand to see if I could... they indeed turned, very very easily. At least they arent seized...

[desrtdog]

Assuming that you have 2 distinct switches on the control panel for each unit? I have a 2010 BB Vision (6-window Handy bus) with 2 TransAir units. This tag is located on the front left firewall - maybe you have something similar somewhere:

As you can see, they are pretty big units (45 KBtu and 55 KBtu, front/rear). Neither was working when I got the bus - inside blowers and condenser fans worked, but compressors not engaging...after replacing seals and charging them, now both work. The evaporators are located in the front/rear caps; condensers are on the left side of the bus. I kept both for max cooling while driving - a necessity down south.

I did install a slide out 6KBtu window unit (sorry ewo1!...didn't really have space for a mini split) for use when parked and on shore power, but that will not cool a hot bus. The factory installed units will make the inside like a meat locker though, and with that, I think the window unit should keep things comfortable. (Note that I have an interior space that is about 19ft long, including driver's area.)

I agree with ewo1 - think about it before removing anything...but if you do decide to remove the rear unit, perhaps the mini split condenser will fit in that skirt space...

[desrtdog]

"IMO, window unit are ugly, unprofessional and reflects one took shortcuts!"

"Agreed on the window units"

...man, you guy are hurting my feelings...
This doesn't look that bad, does it?

[dalez]

The slideout makes it look better And nice use of the swing arm!

One set of controls on mine. No spec plate anywhere I can find. Checked on the evaps and condensers, the firewall, inside the electrical panels, all over the interior, nothin. The most I see is part numbers on the various units, but they're so old Transair has nothing on them anymore. I DID find a circuit diagram up inside the rear evap, although it's pretty hard to see given it's behind the hoses and wires

[ewo1]

Originally Posted by desrtdog

"IMO, window unit are ugly, unprofessional and reflects one took shortcuts!"

"Agreed on the window units"

...man, you guy are hurting my feelings...
This doesn't look that bad, does it?

LMAO....at least it's a slide out!

[cadillackid]

sorry but have to agree the window unit looks ghetto.. just my opinion.. not based on any facts other than aesthetics..


OK driver A/C.. that evaporator looks pretty small ... im going to guess its prob only 9000-12000 BTU... if it has any model numbers on it i might be able to find some info on it in regards to capacity.. tyou will lose some capacity on it just going form its original R12 to 134A... if you were willing to run "unconventional" refrigerants.. (might be flammable).. i can probably get most all if not more of that capacity back..



id want 20,000-30,000 to cool 6 feet of a bus... I have 30,000 in my superior and with a clear shower curtain behind the first row of seats its comfortable on a 92 degree day (dewpoint 70).. and starting to get a tad warm when its 97 out...



so yes you can remove one compressor,
yes you can remove one condenser..


yes you can pipe everything back together for a single system.. obviously before you throw anything away you'll want to leak check whatever you are thinking of using..


is that using the GM A6 axial style compressors.. one on each bottom corner of the engine? if so you'll have more than enough compressor power with one compressor and could likely run an evaporator up to 36,000 if the condenser is a 2 fan and up to 50,000 if its a 3 fan.. that leaves some headroom for hot road / engine air recirculation into the condenser..



hoses.. you'll wasnt to run a #12 for the suction line, #10 discharges, and #8 for the liquid line.. you could run #6 liquid if you keep that little guy up front..


these units run TxV so having an oversize condenser wont hurt anything.. they just regulate the flow down and have a cycling switch of the coil temp drops too low..



in the case of my superior i would definitely choose to cool the whole bus if i could.. but the IH 392 just doesnt have the space to mount dual compressors and have enough belts to drive them so im stuck with 1..



it made a big difference in my overall comfort in the DEV bus adding that rear unit and second compressor and cooling the whole bus vs the shower curtain i had halfway back previously... ive got that A/C system dialed in where even with completely stock interior, non tinted windows i could get it in the low 70s going through texas in august.. houston, dallas, austin, san antonio...

[dalez]

Compressor on each bottom corner of the engine, pic below.

Part Numbers:

201116 - Front Evap
202414 - Rear Evap
301153 - both rear left and right condensers

Wouldnt be surprised if I could get another one or two of those small front evaps from a bus scrap yard

Also would consider putting the copilot chair on a swivel over the front stairs and hanging an insulated curtain right behind the driver's seat...

I'd expect I may occasionally be driving in temps exceeding 100F.

And you're right, this is probably R12 being a '91 isnt it?? Well, I'm not opposed to using a hydrocarbon substitute. The likelihood of explosion is pretty low in reality.

[cadillackid]

Originally Posted by dalez

Compressor on each bottom corner of the engine, pic below.

Part Numbers:

201116 - Front Evap
202414 - Rear Evap
301153 - both rear left and right condensers

Wouldnt be surprised if I could get another one or two of those small front evaps from a bus scrap yard

Also would consider putting the copilot chair on a swivel over the front stairs and hanging an insulated curtain right behind the driver's seat...

I'd expect I may occasionally be driving in temps exceeding 100F.

And you're right, this is probably R12 being a '91 isnt it?? Well, I'm not opposed to using a hydrocarbon substitute. The likelihood of explosion is pretty low in reality.

yeah those are the typical A6 compressors.. those are newer models but these are basically the same compressors that gave GM cars that wickeduly cold A/C they had back in the 60's and 70s...very high capacity for their size.. ive seen a pair of these have enough capacity to cool a decent sized older GMC coach bus..



I may or may not have been running an HC refrigerant in the 1981 cadillac fleetwood brougham that I ran into the side of the semi truck at close to 70 MPH on a summer day back in 97.... and there was no fire...the digital climate control was set to '60' and 'high'.. lots of steam from that 4 core aluminum radiator getting flattened...


another small evaporator connected in parallel to the first would definitely work.. or if you could find a single bulkhead unit.. (bulkhead units get partially recessed into the cavity above the windshield)..



red dot makes a lot of smaller units that could be parallel from your existing front evap..


https://www.partdeal.com/red-dot-duc...YaAghyEALw_wcB


a full bulkhead evaporator.. this would work with a 3 fan condenser and one compressor.. (by itself not in addition to the existing)... there are various cover panels with vents available... it would mount anove the windshield partially in the cavity ...



https://buspartexperts.com/products/...khead-bh20-rac

[desrtdog]

Originally Posted by cadillackid

sorry but have to agree the window unit looks ghetto.. just my opinion.. not based on any facts other than aesthetics...

....well then... to my 'hood...

...Think I need to find someone to tag a little graffiti to the AC access hatch:

[ewo1]

Originally Posted by desrtdog

....well then... to my 'hood...

...Think I need to find someone to tag a little graffiti to the AC access hatch:
Attachment 78972

great place to put up a vinyl map of the us so you could put stars to places where you traveled to....

Or maybe paint it black to match the window colors....or if your feeling really creative, I got extra window frames, replace that metal lid with a folding window ???

It only looks ugly to me when traveling down the road, while parked ...who cares !

[cadillackid]

Originally Posted by ewo1

great place to put up a vinyl map of the us so you could put stars to places where you traveled to....

Or maybe paint it black to match the window colors....or if your feeling really creative, I got extra window frames, replace that metal lid with a folding window ???

It only looks ugly to me when traveling down the road, while parked ...who cares !

true.. it is in fact less ugly than a minisplit mounted way at the top of a bus

[dalez]

Originally Posted by cadillackid

true.. it is in fact less ugly than a minisplit mounted way at the top of a bus

On my bus, it's looking like I'll have to choose to mount my minisplit condenser unit either above the rear window sticking partially above the roof line, or under a rear skirt after pulling an existing condenser - and partially hanging below the skirt line. The only other place is below the rear window, and that would make accessing the hitch a bigger pain and could endanger the jack on the trailer, so really untenable.

[desrtdog]

Originally Posted by ewo1

great place to put up a vinyl map of the us so you could put stars to places where you traveled to....

Or maybe paint it black to match the window colors....or if your feeling really creative, I got extra window frames, replace that metal lid with a folding window ???

It only looks ugly to me when traveling down the road, while parked ...who cares !

That there is a high quality custom stainless steel access cover...gives it a kind of Tesla Cybertruck look...

...oh, wait, that might not be such a good thing...

[cadillackid]

Originally Posted by desrtdog

That there is a high quality custom stainless steel access cover...gives it a kind of Tesla Cybertruck look...

...oh, wait, that might not be such a good thing...

100% cybertruck look is a GOOD thing!..

[DeMac]

Originally Posted by cadillackid

100% cybertruck look is a GOOD thing!..

----------

They get alot of attention, too. The haters invest more into Tesla, than any other brand of truck. Literally, everybody tells about them.

Haven't heard so much talk about an American truck since late '93, when Dodge introduced the new RAM 1500, replacing the tired '70s design being sold earlier that year.



In the year thats followed, Dodge converted alot of Ford & GM owners, while simultaneously attracting a new group of consumers, who had not previously owned a pickup.

[Kentucky Dreaming]

I still love my 2013 Chevy Silverado 1500. It has taken me, my boat, 2 deceased mutts, and 2 current mutts to many happy places in the last 12-1/2 years.

Maybe one day the current pups and I will go to Columbus and visit cadillackid!!!

Just kidding, dude.