A/c recharging


#1

I hooked up the pressure gauge to my car today to check psi in the system prior to recharging and got 0 PSI (refrigerant disconnected), which seems impossible because the compressor was engaged and the a/c was cooling to around 60 degrees.



Does my can of refrigerant need to be at the other end of the hose for pressure to register ? I don’t want to risk recharging w/ a bad gauge in order to not overcharge the system. Advice ? Thanks.



jeff


#2

Update: I tried checking the pressure with the can connected at the other end (was careful to not puncture the can) and still got 0 PSI. Do I have a bad gauge or is 0 PSI correct and I should just go ahead and charge until the pressure is within the proper cooling range ?


#3

Zero is not correct.


#4

I concur. Bad gauge.


#5

Question, Are you sure you are not connected to the vacuum side?


#6

It’s also likely that the pin in the gauge connector is not depressing the valve in the car’s service fitting for some reason.


#7

what are we working with? (FGS),year ,make ect.)R12,134-A. full gauge set (wal mart stuff)need more info?

and when in doubt charge by temperature.

you say 60 degrees ,I respond what was the ambient temp?

dual A/C? single unit?


#8

The suction side is the charging side. The pressure should still be 25-45 psi. Any lower, and the low pressure sensor will turn off the compressor. The one in my car trips at 18 psi. The high side uses a much larger port, and can get to 250-375 psi. You cannot fit a charging port to the high side by accident with an R-134A system.


#9

87 Accord, 134a, partial gauge set (low side only)

Ambient temp was approx 70 degrees.

Single A/c

Should I throw out that gauge and try another ?


#10

so i assume it has been converted to 134-A ?


#11

Yes


#12

Hopefully, no one bypassed the low pressure cutoff switch.

Make sure the new service port is full screwed down onto the old valve. I suspect ok4450 is correct that the valve pin isn’t being fully depressed.


#13

is that the same gauge that came with the can of 134a? because their not accurate at all.they sell better gauges seperate from the can.that is what i had to do.