MVAC Recharge Pressure
#1
06-23-2013, 10:03 AM
Join Date: Sep 2012
Location: South Texas
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MVAC Recharge Pressure
Hello all, I have a question about the a/c pressure listed in the Dodge FSM.
I think that besides the alternator, the mvac system is the only component of my 200,000+ mile Dodge that I have not altered or messed with in any way. It has always blown cold, and I've only added about 16 oz. of 134a in the past 5 years.
However, while installing an efan and trying to locate the A/C clutch power circuit, I was looking at an section 24 of the FSM (page 2732) and came across a chart that seemed to suggest that I could a LOT more refrigerant.
At an ambient temperature of 90 degrees, the low side (suction) pressure should be 50-60 psi and the high side (discharge) should read 215-270.
At an ambient temperature of 100 degrees, the low side should be 60-70 psi and the high side should read 270-330 psi.
At an ambient temperature of 110--a very realistic occurence in South Texas-- the low side should read 70-80 psi and the high side should read 340-370 psi.
Currently I am running roughly 48 psi suction and 225 discharge at 99 degrees ambient with the a/c on max cold and 1500 RPM. And of course since I was hooked up to the high side I unseated the discharge ball valve when removing the gauge. But it is capped and holding refrigerant.
My question is if anyone has ever tried to get their mvac system close to the specs listed in the FSM. Those values seem insanely high, and while I would like to go to 60 psi I cannot imagine a "normal" reading at the values listed in the FSM.
I wish I were the kind of guy that could say things were fine the way they are, but I am also imaging how much colder my a/c could get and wonder if anyone actually had the guts to try and fill their system to those values.
If I am misreading that chart, please let me know. Fortunately, my girlfriend has the truck this week, so I cannot screw this up anytime soon!
I think that besides the alternator, the mvac system is the only component of my 200,000+ mile Dodge that I have not altered or messed with in any way. It has always blown cold, and I've only added about 16 oz. of 134a in the past 5 years.
However, while installing an efan and trying to locate the A/C clutch power circuit, I was looking at an section 24 of the FSM (page 2732) and came across a chart that seemed to suggest that I could a LOT more refrigerant.
At an ambient temperature of 90 degrees, the low side (suction) pressure should be 50-60 psi and the high side (discharge) should read 215-270.
At an ambient temperature of 100 degrees, the low side should be 60-70 psi and the high side should read 270-330 psi.
At an ambient temperature of 110--a very realistic occurence in South Texas-- the low side should read 70-80 psi and the high side should read 340-370 psi.
Currently I am running roughly 48 psi suction and 225 discharge at 99 degrees ambient with the a/c on max cold and 1500 RPM. And of course since I was hooked up to the high side I unseated the discharge ball valve when removing the gauge. But it is capped and holding refrigerant.
My question is if anyone has ever tried to get their mvac system close to the specs listed in the FSM. Those values seem insanely high, and while I would like to go to 60 psi I cannot imagine a "normal" reading at the values listed in the FSM.
I wish I were the kind of guy that could say things were fine the way they are, but I am also imaging how much colder my a/c could get and wonder if anyone actually had the guts to try and fill their system to those values.
If I am misreading that chart, please let me know. Fortunately, my girlfriend has the truck this week, so I cannot screw this up anytime soon!
#2
06-23-2013, 10:19 AM
There was another thread here recently from another member recharging his a/c..... He used the factory specs, and even with ambient temps in the 90's, had outlet temps below 50..... Check your outlet temps, see what they look like. Going by the numbers you show, there may be some room for improvement.