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View Full Version : Vintage Air evaporator unit vents?



chevynut
07-02-2015, 01:48 PM
Guys, I just re-installed my VA Sure-fit evaporator to see how my hoses are going to fit and make sure I can remove the console if needed. The unit has an under-dash center outlet that has vents in it that I don't plan to use. One thing I just noticed today was a second small opening behind the large one. What is it for?

It really still pisses me off that VA lied to me when I asked about when their 55-56 Gen IV Sure-Fit system would be available. At the time they only had the cable system, and they told me they had "no plans" to offer the servo system for the 55-56 systems though they were available for the 57. It wasn't a year later that they were on the market, and I'd already bought the cable system from them.

http://www.trifivechevys.com/attachment.php?attachmentid=4589&stc=1

chevynut
07-02-2015, 01:51 PM
The other thing is that I looked for installation instructions and wiring diagrams for the cable-type units on their website, and it looks like they don't even have them. You would think they would still have them available.

chevynut
07-02-2015, 03:36 PM
I found the instructions for the cable-operated units in their "obsolete systems" link. I can't find anything that says what that rear duct is for. It seems like a really narrow duct compared to the front one. I'm suspecting that one is for heat, and the other is for Air Conditioning with no mixing based on the looks of the rest of the box....that sucks. So if i'm understanding this correctly, I never get any heat out of my A/C ducts? And now I have to figure out how to get heat out from inside my console.

Rick_L
07-02-2015, 05:16 PM
Since I have a cable operated system that I too bought prior to VA offering the electronic control system, I had to review what's what after reading your questions. I am quite sure you are correct, the second smaller outlet is for the heat.

Cable operated VA systems don't have any way to get heat out of the a/c vents, or to mix. Actually I'm not real sure what the electronic controlled systems are capable of in that regard.

A small note on the floor heat with a console. My 09 GMC has no floor heat outlet on the driver side with the console. I guess they thought it was too much trouble, or the console was 100% afterthought, and the HVAC people weren't even consulted. So I HAVE to use the a/c ducts to route any heat to me while driving. I'd be really pissed if I lived in a colder climate. Mixing heat and dry a/c cooled air to the defroster outlets also helps a lot when it's cool, wet, and rainy. Which is a bigger deal for me in warm climate than "defrosting".

As for VA telling you that they weren't going to offer an electronically controlled system, well you know better now. And I'm sure that was never the case, just that the phone guy wasn't clued in on what was really going on. As a reality check, they announced the electronic control 57 system far before it was ready, and they had lots of problems with them even after they were shipping them. As I recall there was a 12-18 month delay between accepting orders and actually selling working systems. A good friend had one of the first 57 systems shipped, and he had to get circuit boards replaced twice before it worked. In fact he went through the second replacement deal right in the VA shop, where they made a board revision with his car as the first prototype. To add insult to injury, I worked on the system and added some refrigerant after his trip to San Antonio - they couldn't even get that right.

Just think what a nightmare you'd have if they shipped you a prototype unit back then, and then you never installed it until now.

Also to put things in perspective, getting the a/c installation worked out is probably far more important than "one touch" exhaust cutouts. You may want to ditch the unit you have and get a new electronic one.

chevynut
07-02-2015, 08:14 PM
Cable operated VA systems don't have any way to get heat out of the a/c vents, or to mix.

That's what I was afraid of. How fricking hard is it to mix hot and cold air in a box anyhow? :(


A small note on the floor heat with a console. My 09 GMC has no floor heat outlet on the driver side with the console. I guess they thought it was too much trouble, or the console was 100% afterthought, and the HVAC people weren't even consulted. So I HAVE to use the a/c ducts to route any heat to me while driving. I'd be really pissed if I lived in a colder climate. Mixing heat and dry a/c cooled air to the defroster outlets also helps a lot when it's cool, wet, and rainy. Which is a bigger deal for me in warm climate than "defrosting".

So what goes to the defroster ducts, hot or cold air? This makes no sense...if I'm using A/C I don't want hot air on the windshield and vice versa. Seems like these cable units weren't a lot better than the original system in these cars....but at least you get A/C. I really don't need heat since I doubt I'll drive this car much in cold weather. ;)


As for VA telling you that they weren't going to offer an electronically controlled system, well you know better now. And I'm sure that was never the case, just that the phone guy wasn't clued in on what was really going on.

As I recall, it wasn't just me who called them asking about it. There were several guys waiting for them. I was willing to wait up to a year or so but when they told me they had "no plans" to introduce one for a 55-56, I decided to go ahead and get the cable unit.


You may want to ditch the unit you have and get a new electronic one.

To tell the truth, I would consider it if they hadn't changed the whole goddam mounting scheme on the new units. Why the hell didn't they just change the cables to servos and leave the mounting alone? At this point I don't think I want to screw around welding new bolts to the firewall and trying to fit it in.....and pay another $800 for something I already have. It's just so frustrating. :(

WagonCrazy
07-03-2015, 12:57 PM
Just think what a nightmare you'd have if they shipped you a prototype unit back then, and then you never installed it until now.


Oh crap. I have the servo unit that came with my 57 Nomad when I bought it 5 or something years ago...And I'll bet it was 2 or more years old at that point...
Guess I'm gonna find out once I get it installed and start testing it out...

chevynut
07-10-2015, 03:02 PM
Cable operated VA systems don't have any way to get heat out of the a/c vents, or to mix.

Is there any reason you couldn't dump both heat and A/C into the same plenum? There are two vents on the unit, one for heat (near the firewall) and the other for A/C. Why do they have to be separate? When you run A/C you turn off the heat and vice versa, so why do they have to come out of different vents?

I'm trying to figure out how to get hear and cold air out of my unit, and both vents now dump into my console. I have no idea how I'm going to get them to come out separately but I could use my console as a plenum to direct air to the vents. Why couldn't this be done? The car's interior is just a big plenum anyhow, right? ;)

chevynut
07-10-2015, 03:54 PM
I just noticed that they offer a 4-vent version of the Gen IV evaporator, instead of the under-dash vents. Anyone have a picture of one of them? I can't seem to find one specific to the '56. It would solve some of my problems, but probably creates some others.

I think you get both hot and cold air out of the same vents with it. The problem is I already have all my interior lines made up, all the mounting stuff welded to the firewall, and who knows what all I'd have to re-do if I upgraded. Maybe I should buy the empty evaporator box from VA and see how everything fits.

chevynut
07-10-2015, 04:31 PM
I found some drawings of the Gen IV in their installation instructions. However, there seems to be two versions of the 4-vent system and one is obsolete:

http://www.vintageair.com/Instructions2013/906156.pdf
http://www.vintageair.com/08/INSTRUCTIONS/55-56%20Chevy/Evap%20Instr/55-56%20GEN%20IV%204%20Vent%20Plnm%2056156-PCZ%20%20Rev%20B%202%207%2007.pdf

It looks like the plenum is removable and you can change it out. The one that has all the vents coming out the driver's side looks like the new version. They probably did that to balance the airflow, but it looks like it would make routing the hoses much more difficult.

WagonCrazy
07-10-2015, 05:13 PM
Ya know Laszlo, with as much time and money as you've put into your Nomad...you might think about selling that old unit and bit the bullet and get the newest unit. Especially if you think the functionality of the servo units and the design tweaks make the new ones considerably better. Just my 2 cents here, but the climate control system inside your car is going to drive you silly if it's not working as optimally as it should...

and I wish they made a dual AC unit for the wagons...so I can get some cool air in the back. I dont' think these units put out enough volume for wagons. I have a VA cable system in my 9 passenger wagon now, and it blows hard, but it's all coming from teh front of the wagon. It takes 30 minutes to cool down the inside on a hot day, and even then it's marginal. All that glass on a wagon acts like a greenhouse...

chevynut
07-10-2015, 05:21 PM
Paul, after messing with trying to figure out how to hook up hoses to the other two vents with the old unit, I think you may be right. That's why I've been looking at the Gen IV units. I've been trying like hell NOT to re-do a bunch of stuff on this car that I've already done, or I'll never finish it. :(

I could probably eBay my older cable unit and get most of my money back. It's never been used, just used as mockup and I have all the parts. If anyone here is interested let me know. I think I paid $675 plus shipping for it.

I wonder if they have the option for the orientation of the outlets. Mine might work better with the old setup if the hoses don't hit my radio. I guess I'll have to give them a call and see where I can get the best deal on a new one. Now I have to weld on that finished firewall again and make up all new lines. :mad:

Rick_L
07-10-2015, 05:56 PM
Wagoncrazy, I know you won't see it in a catalog, but I'm pretty sure I've seen dual air setups done with VA components. In a very coarse sense, it wouldn't be any different from the setup that's been used on Suburbans for 40 years or so. Basically you have two independent evaporator units and one compressor, condenser, and drier. The high pressure is just tee'd after the drier, and the low pressure is tee'd between the evaporators and the compressor. You might want to call the VA tech line, or one of their better installers. Or if you have an a/c tech that works on everything, talk to him. I just don't think it's that hard technically. Your biggest challenge will be plumbing the lines to the rear unit, and placing it where you get good airflow to the passengers.

An alternative is running ducts for cold air through the console area or on the floor under the seat. Lots of high end cars and mini-vans do this to get cold air to the rear seat area. I think that's a bit harder, and there may be a question of whether that's a problem for the VA fan - probably is.

WagonCrazy
07-27-2015, 06:46 PM
An alternative is running ducts for cold air through the console area or on the floor under the seat. Lots of high end cars and mini-vans do this to get cold air to the rear seat area. I think that's a bit harder, and there may be a question of whether that's a problem for the VA fan - probably is.

Good comments Rick. I've thought about it alot, and I think I'm going to plumb a duct thru the center console and point it at the rear seat to at least move SOME cold air to the back of the wagon.

In today's Yukon XLs and Suburbans, the air comes out of the cieling vents in the rear. That would be tough to plumb in on a Nomad, althewhile keeping that stock headliner and chrome bow setup looking original. Could be done though, with oblong plastic tubing inside the headliner. It's where the roof sheetmetal seams to the pillar and window frame sheetmetal that the duct would have to pass thru though. Way more work that I want to imagine at this point.:eek:

Rick_L
07-27-2015, 07:18 PM
Really old Suburbans have the second evaporator mounted just above the liftgate window, with vents right there. Kind of like an underdash unit would have. You don't have as much room as those in a Nomad, but VA probably has some evaporator cases that are smaller height wise than those Suburban units.

Also some mini vans and SUVs have outlets in arm rests, etc. I also see them in the rear of the console as you suggest. You could put the evaporator in the cargo area. If it's on one side, your challenge would be to run a duct to the other side. Perhaps you could mount the evaporator or ducting under a false floor in that area. I think you want the a/c outlets at least medium high or even at the roof since cold air sinks.

Again I think this has been done and VA could help you with the components.

chevynut
07-27-2015, 08:24 PM
Paul, I really don't care if the back of my car gets cool or not, as long as I'm cool. lol! :) I have smoked glass everywhere except the windshield, so that should help some. Also insulating the roof well has to be a big deal on a wagon.