A/C High side Low side PSI readings?

ekliptik · 05-25-2011, 04:53 AM

i have tried searching here as well as google and i can not for the life of me find this.

does anyone have the proper psi readings for the high and low side when operating perfectly?

my compressor seems to cycle on and off quite often and the a/c is only blowing cold when the compressor is engaged, naturally. this would normally indicate a low charge so i added some refrigerant but it did not help at all.

i have a full gauge set as well as 609 certification. just need the proper psi readings for normal operation.

thanks for your help!

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Zoom49 · 05-25-2011, 07:08 AM

Here is the info from the RX-8 service manual. It is most likely the
evap temp sensor turning off the clutch.

ekliptik · 05-25-2011, 04:36 PM

ahh yes i forgot to mention i saw that and my pressures are within those measures. however i was thinking that chart had a pretty wide range of acceptable psi readings.

maybe someone with perfect working a/c can hook up a gauge set to their system and give me a working psi reading with the compressor engaged thats a little more precise.

i'd reaaaally appreciate it.

Zoom49 · 05-26-2011, 12:24 AM

[QUOTE=ekliptik;3987347]ahh yes i forgot to mentionreadings.
maybe someone with perfect working a/c can hook up a gauge set to their system and give me a working psi reading with the compressor engaged thats a little more precise.
QUOTE]

Auto A/C is not like home A/C, in that you do not attempt to charge a system with guage readings. The only way to accurately determine charge is to recover the current charge, then recharge by weight.

At the same ambient temp the high side can vary by 50 psi and about 8 psi on the low side. My system suffered premature clutch cycling. The evaporator probe was turning off the clutch at 44 degree coil temp. I changed the placement of the probe to get it to cycle at 34 degree coil temp which in turn lowered my duct temp by about 11 degrees.

I see you are in Vegas. The guys at Auto Air & More on Trop have won the car A/C tech of the year award twice. May be time to go see them.

ekliptik · 05-26-2011, 01:28 AM

thanks for all your input so far. it really is a help and i appreciate it.

609 is the automotive a/c certification.

i'd like to recover all the refrigerant and refill if i had a system to do so.

ive been able to add refrigerant to many cars with low charge and just add till i get the psi in the right range for a given vehicle. the rx8 is the first time ive come across a car with such a wide range of acceptable psi readings.

if my psi readings are correct and the amount of refrigerant that is in the rx8 is acceptable or close to it then im going to have to look into why the clutch is cycling sooo often. it is not staying engaged for very long before it disengages at the moment.

is there a good way to test the evap temp sensor with a ohm meter or something?

thanks for the recommendation to that a/c shop but i'd like to fix this on my own as my self labor rates are muuuuuuch cheaper im sure.

Zoom49 · 05-26-2011, 07:27 AM

Quote:

Originally Posted by ekliptik

i'd like to recover all the refrigerant and refill if i had a system to do so. I try to get this done, may be overcharged
it is not staying engaged for very long before it disengages at the moment. May be overcharged
is there a good way to test the evap temp sensor with a ohm meter or something? See attachment

i'd like to fix this on my own as my self labor rates are muuuuuuch cheaper im sure.

Hope this helps

ekliptik · 05-26-2011, 01:45 PM

thanks once again for the pdf on the evap sensor.

ur right. the a/c may very well be overcharged. the reason it didnt cross my mind is because i bought the car from a owner who bought it new about 3 months ago.

from what he told me the a/c has never been worked on or charged. the symptoms i have now are from when i first purchased the car as the second owner. with those symptoms and history first thing that came to my mind is its just simply low charge.

i guess it would be worth the cost of a can or 2 of r134a to deplete it completely and charge it up by amount. i'll see where i stand from there. once i know for sure how much refrigerant is in there, if the symptoms still exist i'll test out the evap sensor.