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A/C system 100% new and not working right


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ReddyK
New User

May 27, 2018, 7:06 PM

Post #1 of 9 (310 views)
A/C system 100% new and not working right Sign In

Hello,
I have an 86 Camaro and have replaced every part of my A/C system with NEW parts except for a rebuilt compressor. The vent temps are are 80 degrees and both high and low side pressures are high. Trying to diagnose I have checked and replaced the orifice tube a couple of times 1 white and 1 blue one. The blue tube gave about 5 psi lower pressures. I blew through all the parts with 134a and didn't find a restriction. I felt like the system might have uncompressible stuff inside like water/air since both pressures were high so I replaced the dryer and orifice tube again and got the same results. I added 28 oz of 134a. Less refrigerant had no better cooling and more resulted in even higher pressures. I have an electric fan and a new radiator also.Here are my specs.
Label says 2.25 lbs R12 -- I added 80% of 134a 28ozs.
8 ozs PAG 150
Vacuumed for 30 min at 29 mmhg
Heater hose pinched off.
Ambient temp 80 degrees
750 RPM
Low side pressure 48 psi
High side pressure 260 psi
Evaporator exit temp 63 degrees
Condenser inlet temp 130 degrees
Condenser outlet temp 103 degrees
Vent temp 80 degrees

1250 RPM
Low side pressure 34 degrees
High side pressure 305 degrees
Vent temp 75 degrees

1250 RPM Wetted down the condenser
Low side pressure 30 psi
High side pressure 205 psi
Vent temp 90 degrees

Any suggestions would be greatly appreciated. I have been working on this for a week and am about ready to take it to someone else.


(This post was edited by ReddyK on May 27, 2018, 8:50 PM)


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

May 27, 2018, 9:19 PM

Post #2 of 9 (282 views)
Re: A/C system 100% new and not working right Sign In

What is the ambient temperature when you took those measurements? What are you using to measure temperature at the pipes? Are you using an infrared temperature gun? Guns aren't accurate on shiny pipes or measuring outlet air temps.

Electric or engine driven fan(s)?
How long was the AC running when you took those pressure readings? What was the temperature of the interior of the vehicle? What is the temperature difference between the suction and liquid lines at the firewall?

I find it strange that your outlet temp went higher when you watered the condenser even though your system pressures decreased.

If you run your hand across the front of the condenser, do you feel any drastic temperature changes?

Sorry for all the questions, but the more info the better.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


ReddyK
New User

May 27, 2018, 9:34 PM

Post #3 of 9 (270 views)
Re: A/C system 100% new and not working right Sign In

Thank you for your reply.The ambient temp was 80 degrees and yes I was using a infrared heat gun. Would an instant read be better? I'll try one of those.
I have an electric fan. I ran it for 10 minutes before I wrote down the readings and it was 90 degrees inside the car.When I watered down the condenser the evaporator in/out tubes went from cool and sweaty to just warm.
I will check the evaporator in/out temps and the change in the condenser temp from one side to the other and post back.Thank you,Steve


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 28, 2018, 6:30 AM

Post #4 of 9 (253 views)
Re: A/C system 100% new and not working right Sign In

Quick read, sorry Steve. It's too high of course and no performance but a differential so what can do that is on my mind? Pinching heater is good to rule out heater core but is cool going elsewhere?


Heat gun? Love them, not for vent temps use a meat thermos type center vent and look if tight underdash dryer vent like things I think used are in position to vents.
Easy on the 80% rule you seem a bit over inconclusive right now. New parts do NOT use the same as OE specs, none do so know that. They use a lot less even if you kept it R-12.
As DS said feel the inlet outlet right at the firewall should feel by hand even they should be real close when perfect on this.
Other? Is the dang "O" tube in the right direction? Some can go in backwards messes up the whole show or a hose had another if you have two you really get messed up readings and no performance,


T



ReddyK
New User

May 28, 2018, 9:24 AM

Post #5 of 9 (247 views)
Re: A/C system 100% new and not working right Sign In

Yes, the instant read thermometer was much more accurate and stable temperature measurements.
I am 100% sure the orifice tube is in the correct direction and there is only one. This last time in installed a variable orifice tube.

Here are the new conditions:

Across the front of the condenser the temp was 142 on one side and 120 on the other.

Re-circulation door was not opening to the recirculate position. It is now open and the vent temp has dropped to 50 degrees.
Ran for 10 min.
Ambient air temp 74
Inside car temp 74


1250 RPMvent temp 50 degrees
low side pressure 28 psi
high side pressure 260 psi
evaporator tube in temp 38 degrees
evaporator tube out temp 36 degrees
condenser tube in temp 192 degrees
condenser tube out temp 120 degrees

I know it is cooler today and getting the recirculate door open made a big change. I still feel like the pressures are too high and the inside temp is not low enough. I think I will try to adjust the refrigerant level down first and see if I get any major change.
Thank you all for your help,
Steve


Tom Greenleaf
Ultimate Carjunky / Moderator
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May 28, 2018, 12:13 PM

Post #6 of 9 (236 views)
Re: A/C system 100% new and not working right Sign In

! Did you say you found anything A/C part at a real 192F ?? That's WAY too hot system should shut down if you put a HPCO on this thing all suggests way too much refrigerant. 192F if real is over 400 PSI system should default to shut down.
Arggh - if you have to I call find your own charge amount that is real close to perfect and know system is in order but found that door not right you can but it takes ages to get that right and ambient temp and engine heat plus surface if checking outdoors is much hotter than you think coming in thru condenser throwing you all off.


Get the dang fast meat thermos type or now hard to find WIRED remote meant for home use out a window and place it on dash so you see it while working. Give it time to stay steady before trusting that's the spot you want and don't get greedy more just causes problems or disasters,


T



Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

May 28, 2018, 5:49 PM

Post #7 of 9 (222 views)
Re: A/C system 100% new and not working right Sign In

Tom, look at his inlet and outlet temps at the evaporator. He also stated the lines were sweating in previous post.

You would think wetting the condenser and bringing system pressures down would lower air duct temps if mix door was performing correctly. Have you tried driving the vehicle at cruising speeds with your gauge set plastered to the windshield to see what happens?

I would be led to believe there has to be something going on with blend door control, chamber box air doors, or the blend door is leaking. Hot interior or leaking door seals will not help with efficiency until the cabin gets cooled down also.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on May 28, 2018, 6:02 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 28, 2018, 6:08 PM

Post #8 of 9 (214 views)
Re: A/C system 100% new and not working right Sign In

Missed that - sorry. Yes if not the same by even feel have to find out why. Dang plastic junk where they probably pivot could even wear out and not function worth a crap?
Egg-hausted, I'll check back later on this one, Tom


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

May 28, 2018, 8:15 PM

Post #9 of 9 (203 views)
Re: A/C system 100% new and not working right Sign In

A reman compressor on a retrofit R12 system? I don't see that ever being reliable or cooling properly, especially if it's an R4. It's a little better if it's an A6.

He added 8 ounces of PAG 150 which is too heavy to start with and I would bet that reman compressor came with oil already in it.

I'm thinking this thing is overloaded with too much oil. It also seems to have condenser/cooling fan issues



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