Remote evaporators

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Pghdave

Member
Apr 10, 2022
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I have heard complaints about dash air system. I found 12 volt remote evaporators and wondered if two could be placed in front and back of coach to use while traveling and has anyone done this with success?
 

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It's possible; the ac compressor and condensor have to be able to handle the load (BTU). One nice one I've seen is the addition of two evaporators inside new fabricated side panels next to the driver and passenger seats. Other folks have mounted one under the rear-facing 'booth' seat. The rear of the coach is a long way to run ac lines. Try a google search and/or GMCNet and the associated photo site. Often auxillary evaporator supply lines are fitted with on/off solenoids.
 
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I have a giant evaporator under the couch behind the drivers seat. It blows massive amounts of cold air on the dinette area behind the passenger seat. Using the stock compressor, and R12a / duracool.

No issues with the ac lines, they are only about 6 feet of hose. In contrast, GMC Suburbans from the factory have rear a/c at the back of the truck, and those are at least 20 feet long to go from the compressor, across the engine bay, down to the frame, then the length of the truck, then up to the evaporator.
 
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I have a giant evaporator under the couch behind the drivers seat. It blows massive amounts of cold air on the dinette area behind the passenger seat. Using the stock compressor, and R12a / duracool.

No issues with the ac lines, they are only about 6 feet of hose. In contrast, GMC Suburbans from the factory have rear a/c at the back of the truck, and those are at least 20 feet long to go from the compressor, across the engine bay, down to the frame, then the length of the truck, then up to the evaporator.
Hi, do you have any more information you would be willing to share about this, I am looking into this myself and would love to do this.
 
I have a giant evaporator under the couch behind the drivers seat. It blows massive amounts of cold air on the dinette area behind the passenger seat. Using the stock compressor, and R12a / duracool.

No issues with the ac lines, they are only about 6 feet of hose. In contrast, GMC Suburbans from the factory have rear a/c at the back of the truck, and those are at least 20 feet long to go from the compressor, across the engine bay, down to the frame, then the length of the truck, then up to the evaporator.
This is assuming you have factory AC. My GMC didn’t come with OEM AC but it would be nice to add it then use these remote evaps.
 
Wow I apparently didn't document this on my build page.

I got it on ebay, it's this one: UNIVERSAL UNDERDASH EVAPORATOR NEW JEEP VAN MINI-BUS MODEL 223-100

Here's the description:

"Please do not get confused,​

this item is High Quality
Everyone wants to save money,
but don't be fooled by cheaply made, low cost evaporators which won't perform as advertised.
You get what you pay for.


UNIVERSAL MINI-VAN/JEEP/MINI-BUS AC EVAPORATOR ASSEMBLY


27"W x 11"D x 5 1/2"H
12V
3-Speed
359CFM
22,220 BTU
22 Pass 4-Way All Aluminum Coil
2 Double Shaft Blower Motors
High impact injected plastic case
Fujikoki expansion valve
Mounting brackets, drain hose and T included

****This is NOT a stand alone unit. It will need a compressor and a condenser in order to work properly.****

FREE UPS Shipping for continental U.S. only.
International buyers, including Puerto Rico, Alaska, and Hawaii, contact for quote before buying."

s-l1600.jpg


s-l1600.jpg


I mounted it under the couch behind the drivers seat and ran a/c lines through the step under the couch forward to the passenger side hatch and tee'd in there. Drill a couple holes in the floor to drain. It will freeze out the people sitting at the dinette across the aisle :)
 

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Thank you for this information! If you don't mind some more questions.
Did you tee straight into the Freon lines? I assume this was added in parallel to the existing dash? Did you crimp your own fittings? Any idea how much freon you had to add to the system.
 
Thank you for this information! If you don't mind some more questions.
Did you tee straight into the Freon lines? I assume this was added in parallel to the existing dash? Did you crimp your own fittings? Any idea how much freon you had to add to the system.

Yes I bought fittings online and a crimper from ebay and tee'd into the stock lines. Honestly I didn't add much more R12a than stock, 3 cans maybe? The stock system used R12 and I think the conversion is 40% with R12a, so multiply the stock amount by 0.4(?) and round up to the nearest full can.
 
Yes I bought fittings online and a crimper from ebay and tee'd into the stock lines. Honestly I didn't add much more R12a than stock, 3 cans maybe? The stock system used R12 and I think the conversion is 40% with R12a, so multiply the stock amount by 0.4(?) and round up to the nearest full can.
If you don't mind me asking. Why didn't you do a 134A conversion while you had the whole system apart? Mine has had the conversion was wondering.
 
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Yes I bought fittings online and a crimper from ebay and tee'd into the stock lines. Honestly I didn't add much more R12a than stock, 3 cans maybe? The stock system used R12 and I think the conversion is 40% with R12a, so multiply the stock amount by 0.4(?) and round up to the nearest full can.
Did you consider adding a solenoid for the remote evap coil? I suppose when you want AC, you want all you can get.... Probably would want to switch on/off an evap in the rear if it were fitted.
 
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If you don't mind me asking. Why didn't you do a 134A conversion while you had the whole system apart? Mine has had the conversion was wondering.

I drank the R12a coolaid I guess, it's supposed to have lower pressures, bigger molecule so less leakage, better for your system b/c it doesn't create an acid if moisture gets in, it's compatible with any oil and mostly b/c it's supposed to move more heat than 134a. I think the main reason was that it's meant to be a direct replacement for R12 so it should work as designed with the original system. I didn't want to do any thinking, just make it as original as possible but without the R12.
 
You side that it freezes people out at the dinette. Have you operated this in the summer going down a Texas highway? Just trying to get a feel for how large of a difference it makes. We travel down this summer with no AC, and will never do that again. Mine has a worm clamp on the AC house into the main condenser so when I fix that properly and recharge the system was looking at doing this the same time. I just don't feel like driving in a sauna anymore.
 
You side that it freezes people out at the dinette. Have you operated this in the summer going down a Texas highway? Just trying to get a feel for how large of a difference it makes. We travel down this summer with no AC, and will never do that again. Mine has a worm clamp on the AC house into the main condenser so when I fix that properly and recharge the system was looking at doing this the same time. I just don't feel like driving in a sauna anymore.

Sorry, I don't know that. We only get high 80s / low 90s and high humidity here in upstate NY.