A/C troubles
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A/C troubles
Posted: June 01 2008 08:48 PM
 
Ron Goben (aka ronhotrod) [ View ] [ ronhotrod@yahoo.com ] [ Car Ads ] [ Blogs ]
Mount washington, Kentucky
502-648-0142
 
I put a new V/A system in a '46 Chevy and have major problems. it will cool to @ 43 degrees for a short time and then warm to around 62 degrees. I have changed everything including the evaporator in an effort to repair. three expansion valves, a condenser (which blew up ), the compressor and drier. Everything but replacing the hoses. Head pressuers range from @175/180 to as much as 400 when its not cooling. Has anyone had trouble with hoses collaspesing internally?? Sounds like and acts like a restriction but I can't locate any trouble. Ideas?????
 
 
Comments
 
Posted by dwinspector21  -  06/01/2008 09:12 PM
I assume you're using 134 -A ? Have you weighed in the charge, or are you using gauges? What's the ambient air temp/ do you have a cooling fan that is activated when the A/C is turned on? May be moisture in the system, have you evacuated it? Just a few thoughts......you're right about one thing, sounds like a restriction..... that's where I'd start hope this helps....keep us posted.
dwinspector21 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Kodak, Tennessee
 
Posted by plwheelie  -  06/01/2008 09:07 PM
It sounds like you are over charging the unit.

Evacuate and charge to #25 on low side. 2 cans max! The high side should be about 150#

That is the #1 problem with 134 systems.

Paul
plwheelie [ View ] [ Email ] [ Blogs ] [ Car Ads ] Tahlequah, Oklahoma
 
Posted by ronhotrod  -  06/01/2008 09:11 PM
Forgot to add, yes 134A can't get more than 12 oz in the system. been vaccuumed for over an hour every time I take it apart. Always holds. I have been installing air for over 10 years and have never had this happen before.
ronhotrod [ View ] [ Email ] [ Blogs ] [ Car Ads ] Mount washington, Kentucky Charter Member since July 2001
 
Posted by dwinspector21  -  06/01/2008 09:22 PM
Got a sight glass in your dryer?...My money is on moisture.
dwinspector21 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Kodak, Tennessee
 
Posted by ronhotrod  -  06/01/2008 10:32 PM
yes I have a sight glass, starts out milky and then goes clear. I have vaccuumed multiple times to remove moisture, but maybe......It just acts like a restriction some where but I've run out of ideas. As I said I have replaced the entire system other than the hoses. Can it be they collaspe when inuse???
ronhotrod [ View ] [ Email ] [ Blogs ] [ Car Ads ] Mount washington, Kentucky Charter Member since July 2001
 
Posted by plwheelie  -  06/02/2008 12:12 AM
I had one other problem that kicked my butt on a system like this, The low side port valve stem was too far down inside the fitting that my snap on hose connector wouldn't compress the valve to let freon in unless you pushed down on the connector.

It acted like a restriction, I replaced the expansion valve and inspected the compressor valve plate , flushed hoses etc before I found that one. I also had been using the same fitting to evacuate, but in fact I was only pulling a vacuum on the hoses and gauges.

Just another posibality.

Paul
plwheelie [ View ] [ Email ] [ Blogs ] [ Car Ads ] Tahlequah, Oklahoma
 
Posted by ronhotrod  -  06/02/2008 08:22 AM
Thanks I'll check that out! Maybe I'm not getting what I thought I was. Has to be something simple that I haven't seen yet.
ronhotrod [ View ] [ Email ] [ Blogs ] [ Car Ads ] Mount washington, Kentucky Charter Member since July 2001
 
Posted by hotrodgene  -  06/02/2008 08:59 AM
would also check that heater control is not allowing hot water to increase temp.Pinch off heater hose to test
Gene Riffe [ View ] [ Email ] [ Blogs ] [ Car Ads ] Saint Petersburg, Florida
 
Posted by amy14760yahoocom  -  06/02/2008 09:20 AM
make sure the control probe is in the box under dash that controls how warm or cold the system gets . i had a system that did the same thing and come to find out the system was actualy freezen up . it too destroyed the expansion valves so make sure the system cycles like it is suppose to pump will kick on and off a few times in a minute of running . good luck bob
amy14760yahoocom [ View ] [ Email ] [ Blogs ] [ Car Ads ] allegany, New York Charter Member since July 2005
 
Posted by SAM1951  -  06/02/2008 02:26 PM
try evac over night ....24 hours...sam
SAM1951 [ View ] [ Email ] [ Blogs ] [ Car Ads ] MIDDLESVILLE, Alabama
 
Posted by APLUS  -  06/02/2008 11:43 PM
Make sure that the heater control valve is piped in correctly (it's directional). Also make sure your vacuum pump is working up to par----install a micron gage in-line to see how low it's pulling in microns. That'll tell you a lot more (microns) than inches of mercury will. Charge by weight and if you clear the sight glass with 134a you'll be overcharged. When in doubt---call Vintage Air.
APLUS [ View ] [ Email ] [ Blogs ] [ Car Ads ] Austin, Texas
 
Posted by ronhotrod  -  06/03/2008 11:04 PM
Well here is an update. Scott from Hot Rod Air called after seeing my post and talked with me for 15-20 minutes about the problem I was having. We carefully covered all the obvious items and then began diving deeper. He was both concerned, polite and very helpful. His diagnosis was too much heat build up in the condenser itself. Though I had checked air with a rag in front of the car and feeling the flow through the radiator, he thought that it might not be enough to keep things working as designed. So today I moved the condenser foward (away from the radiator) just enough to install a 14 inch puller fan wired to the compressor. I puller another vaccuum for about an hour, placed a shop fan in front of the car and charged the unit again. This time it cooled to 40 degrees evn and stayed there for about 10 minutes. I then unhooked everything, pulled the car outside and turned the air on again. Inside temperature had gotten to about 65 degrees and the car quickly went down to 42 degrees inside. I'll re-check the thing tommorrow but looks like Scott was right!! Even though it wasn't one of their units, he went above and beyond to help. A BIG Thank You Scott We need more folks like you. Thanks to all that replied and helped this old dummy get it fixed
ronhotrod [ View ] [ Email ] [ Blogs ] [ Car Ads ] Mount washington, Kentucky Charter Member since July 2001
 
Posted by REBORN55  -  06/03/2008 11:29 PM
Glad you got it squared away Ron. Scott was helpful in my a/c install also
Ken [ View ] [ Email ] [ Blogs ] [ Car Ads ] De soto, Illinois
 
Posted by plwheelie  -  06/04/2008 05:32 PM
Not enough air across the condenser would certainly cause the problem. What type fan were you using before?

Paul
plwheelie [ View ] [ Email ] [ Blogs ] [ Car Ads ] Tahlequah, Oklahoma
 
Posted by ronhotrod  -  06/04/2008 10:01 PM
had an electric engine fan that seemed to pull plenty of air. Car ran cool and I could feel the air flow. But obviously it wasn't as good as I thought it was. Lots of opinions on where to place the condenser (next to radiator or not) but I prefer to move it away from a heat source. I usually space it 1 1/2 to 2 inches in front of the radiator in order not get absorb engine heat. I always check air flow and install a condenser fan on 95% of my installs. This customer didn't want one so we tried not to. Again it seemed like plenty of air flow. But, as they say, the proof is in the pudding !!!!!!
ronhotrod [ View ] [ Email ] [ Blogs ] [ Car Ads ] Mount washington, Kentucky Charter Member since July 2001
 
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