R134 hi pressure?????question
Instructor
Joined: Jun 2000
Posts: 128
Likes: 0
From: Friendswood Texas
The Low and High pressure readings represent the systems freon charge and also the calculated or theoretical skin temperatures of the evaporartor (Low) and condenser (high).
For a quick check, set the fan speed (inside) at high and system set to recirculate the air, all of the vents open, the car shaded ( I see your in West Texas so do this with the car out of the direct sun) and most importantly with air moving across the radiator and condensor (setup a box fan in front of the car).
With the car at normal operating temperature and your AC system properly charged, the low side will read about 30-35# (35-40 drg. F) and the high side no more than 150# (112 drg. F). There are a number of other varibles that will impact the reading including the ambient temperature and humidity, mechanical condition of the compressor, expansion tube and the total amount of oil so these are only guidelines.
Keep us posted and good luck.
Robby
For a quick check, set the fan speed (inside) at high and system set to recirculate the air, all of the vents open, the car shaded ( I see your in West Texas so do this with the car out of the direct sun) and most importantly with air moving across the radiator and condensor (setup a box fan in front of the car).
With the car at normal operating temperature and your AC system properly charged, the low side will read about 30-35# (35-40 drg. F) and the high side no more than 150# (112 drg. F). There are a number of other varibles that will impact the reading including the ambient temperature and humidity, mechanical condition of the compressor, expansion tube and the total amount of oil so these are only guidelines.
Keep us posted and good luck.
Robby
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Robby: 150 lbs hi side sounds like the R12 spec and assuming a cool day of around 70F or so. With R134a and the 90f we're having here in TX right now you'll see much higher than that. On my 71 I would expect 240-280 on a day like this.
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Originally Posted by PortDawg
I read someplace you should only fill 134a TO 80 percent of the capacity of the R12. Don't know if that's true but....
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Brett Foote
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Originally Posted by Robby79
Zwede,
No argument from me. I almost didn't reply becasue there are so many varibles that need to be considered. Do we know yet what the measured pressure was?
Robby
No argument from me. I almost didn't reply becasue there are so many varibles that need to be considered. Do we know yet what the measured pressure was?
Robby
Instructor
Joined: May 2004
Posts: 119
Likes: 0
From: Osceola Mills Pa
A/c
Here's the place to go for info: http://www.autoacforum.com/categories.cfm?catid=2
Here is link for a/c evacuation and charging instructions
http://www.autoacforum.com/messagevi...&threadid=7931
Here is link for a/c evacuation and charging instructions
http://www.autoacforum.com/messagevi...&threadid=7931
