Checking Vintage Air Performance

[clemsonteg]

I finished the install of my Vintage Air setup last night and I charged the system with 28 oz of R134a. I was curious as to what air temps I should see from the ducts and when I should be checking it (doors opened or closed, windows up or down, fan speed, moving or idling)?

[motorcritter]

Check it with windows up, and since those systems are recirculate-only, that should get you 38-44 degrees at the centre port, fan on high speed, temperature set to max cold. Any colder, and you get icing of the system (not good), any warmer, well, what's A/C for anyway? I prefer to get frostbite in mid-summer, and I got schooled in A/C work while working in FL. make sure the drain for the evaporator is open and flowing.
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[Fldawg]

if you don't have gauges, the best way to check is measure temp at front of truck were condensor is , open doors to your truck run a/c on recirulate max fan, the temp should be 40 degrees differance at the vents from front of truck if you have a good charge. some people say your crazy .but try it then put a set of gauges on it to check pressures.

[motorcritter]

That 40* difference is an excellent gauge, too, when the ambient isn't too low. I totally assumed that gauges would be used, and pressures monitored for proper levels. It doesn't take much to go from lukewarm to 'snowflakes out the vents', once you get the R134a level close. Low pressure is pretty much set on the Sanden compressor, but upper pressure should be max at ancient temp + 140, IIRC.
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[clemsonteg]

Thanks. It's about 90 today, so I'll put the fan on high and measure the temp from the center vent. I charged the system with exactly 1.8 lbs per the installation instructions. I think my high pressure was around 200 last night with 75 to 80 degree temps

[motorcritter]

Sounds like you just might be ready for summer!
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[clemsonteg]

Originally Posted by motorcritter

Sounds like you just might be ready for summer!
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I hope so. It is actually more for the wifey and the kiddo. I don't mind cruising with the windows down, but I want mama and my little boy to be comfortable. The more they cruise, the more I cruise

On the 10 minute ride back to work from lunch, the inside of the cab was 110* and the air settled around 60*. Hopefully it will do a little better this afternoon on my longer ride home.

[67ChevyRedneck]

The cab temp was 60* or the air out of the vent was 60*?

That's too warm out of the vent even for a short drive. My 65 Mustang's V/A A/C doesn't get as cold as the trucks and it still gets down into the mid-high 40's depending on outside temps.

Did you evacuate the system first and pull a vacuum on it to remove all moisture and check for leaks?

[clemsonteg]

Originally Posted by 67ChevyRedneck

The cab temp was 60* or the air out of the vent was 60*?

That's too warm out of the vent even for a short drive. My 65 Mustang's V/A A/C doesn't get as cold as the trucks and it still gets down into the mid-high 40's depending on outside temps.

Did you evacuate the system first and pull a vacuum on it to remove all moisture and check for leaks?

I did. Vacuum for 45 minutes and leak check for an additional hour. I will check it again this afternoon to see how she does. Maybe I got some air into the system and didn't know it. I may have to evacuate the system and charge it again.

[Wrenchbender Ret]

If you put in 1.8 lbs it is not quite enough. That is 24 oz. The cans we get are usually 12 oz. Look at the sight glass. There should be no foam. I just put one in my 56 & it is ice cold.

[clemsonteg]

Originally Posted by Wrenchbender Ret

If you put in 1.8 lbs it is not quite enough. That is 24 oz. The cans we get are usually 12 oz. Look at the sight glass. There should be no foam. I just put one in my 56 & it is ice cold.

1.8 lbs is what the install calls for and 1.8 lbs translates into 28.8 oz as far as I know since there are 16 oz in 1 lb. it's a little apples to oranges, but how much was your system charged with?

I put a set of gauges back on to measure the pressure and temperature. The outside air temp was 90 degrees and the air from the vent was 54 degrees. At 1500 rpms and the compressor on, the high side saw a max of 225 psi and the low side dropped to 19 psi. With the compressor off, the low side rose to 40 psi and the high side dropped to 150 psi. The static pressure with the truck off was 100 psi.

Any thoughts on the pressures? The other downside to my current setup is that the only insulation in the truck is on the firewall. Everything else's is painted metal at the moment. That obviously helps contribute to my high in cab temps with or without the air.

After reading through the instructions a dozen more times, the only places I can think of that I didn't follow 100% was warming up everything before I evacuated the system and I didn't think to purge the intake line on first can of freon or in between cans. That may have introduced some outside air and moisture into the system.

[clemsonteg]

After an hour in the driveway the best I could get was 50 degrees. I'm not sure if it's my lack of insulation is causing the cab temperature to be high and preventing me from dropping the temp of the air by more than 40 degrees or if I messed something up during the evacuation and freon addition. Maybe I should chalk this one up to a $50 lesson in letting AC people do the evacuating and charging part.

I also saw bubbles and liquid in the sight glass of the drier. Not sure if that is good bad or neither.

[CST10]

Mine blows a cold 42 degrees when 90 degrees outside.

[clemsonteg]

This article is pretty good. I checked most of these items. Some of them could only be done if the system was evacuated and recharged again.

http://www.hotrod.com/how-to/interio...-conditioner/p

[di11avou]

The temp should be measured from the vent closest to the evaporator, blower on high, hood closed, and the rpm raised to around 1000. It shouldn't really matter if the doors are open or if it's set to recirc or not since you don't really need to run it long enough to cool down the whole cab.

For a 134a system, temperatures 25F below ambient temp is considered normal. Some vehicles can cool better than this, but I wouldn't freak out if yours doesn't. If it's really humid outside that can also hurt performance.

[Wrenchbender Ret]

[QUOTE=clemsonteg;7179815]1.8 lbs is what the install calls for and 1.8 lbs translates into 28.8 oz as far as I know since there are 16 oz in 1 lb. it's a little apples to oranges, but how much was your system charged with


Your right. I was adding .8 as oz. instead of 8/10 of a lb.
I put in 2 12 oz cans plus a little more from another. I haven't really used it on a real hot day yet, but the outlet temp. is about 35 degrees.
The site glass has liquid going through it when it is performing correctly. If it is foamy the liquid is breaking down before it gets to the evaporator.

[clemsonteg]

[quote=Wrenchbender Ret;7180143]

Originally Posted by clemsonteg

1.8 lbs is what the install calls for and 1.8 lbs translates into 28.8 oz as far as I know since there are 16 oz in 1 lb. it's a little apples to oranges, but how much was your system charged with


Your right. I was adding .8 as oz. instead of 8/10 of a lb.
I put in 2 12 oz cans plus a little more from another. I haven't really used it on a real hot day yet, but the outlet temp. is about 35 degrees.
The site glass has liquid going through it when it is performing correctly. If it is foamy the liquid is breaking down before it gets to the evaporator.

Thanks. I think if I have a problem, it's most likely related to the evacuation and charge of the system. I either didn't evacuate the system completely or maybe I didn't charge the system correctly by either allowing ambient air in or by overcharging the system.

My current internal debate is whether to try again or to take it and have it serviced by a qualified AC shop.

[clemsonteg]

Looks like my problem was resolved by the guys at VA, Mark specifically. Those guys are really knowledgeable and gave me some easy troubleshooting tips to help resolve my issue in less than a day.

Turns out that the temperature probe that monitors the evaporator coil temp and controls the compressor was inserted too far. I am going to guess that in the half dozen to a dozen times that I had the air box under the dash that I bumped it pushing it too far inward. A simple adjustment now has my air temps at 43-45 degrees. Mark suggested leaving it in that range, much cooler may result in the evaporator becoming frozen and reducing performance.

Thanks for everyone's help. Hopefully this will help someone else down the road!

[motorcritter]

It's always the details, that make the difference.
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[clemsonteg]

Originally Posted by motorcritter

It's always the details, that make the difference.
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Indeed. One of those things that you wish was in the manual. The probe isn't mentioned anywhere. I guess they don't want people adjusting themselves into a problem.

[67ChevyRedneck]

Originally Posted by clemsonteg

Looks like my problem was resolved by the guys at VA, Mark specifically. Those guys are really knowledgeable and gave me some easy troubleshooting tips to help resolve my issue in less than a day.

Turns out that the temperature probe that monitors the evaporator coil temp and controls the compressor was inserted too far.

Awesome! Just in time for holiday weekend cruising, courtesy of all those who have protected us over the years

[clemsonteg]

Originally Posted by 67ChevyRedneck

Awesome! Just in time for holiday weekend cruising, courtesy of all those who have protected us over the years

Yes sir indeed. I didn't see you at the Speedway today. Couldn't make it?

[67ChevyRedneck]

I'm driving the entire hot rod power tour with my wife in my 65 mustang (+\- 3300 miles) in two weeks.

I'm strapped for time. I redid the rear brakes yesterday and added a new cooling system today. Still some more to do!

Matt borrowed my gopro so I hope he made some cool videos.

[clemsonteg]

Originally Posted by 67ChevyRedneck

I'm driving the entire hot rod power tour with my wife in my 65 mustang (+\- 3300 miles) in two weeks.

I'm strapped for time. I redid the rear brakes yesterday and added a new cooling system today. Still some more to do!

Matt borrowed my gopro so I hope he made some cool videos.

I saw one for sure with him driving. One hand on the wheel and one hand on the seat holding on!