Checking the R-134a Refrigerant Charge

  1. Inspect the receiver tank sight glass with the unit operating in COOL. If the balls FLOAT in the receiver tank sight glass, the R-134a charge level is correct.

  2. If the balls are NOT FLOATING in the sight glass, the unit MAY be low on R-134a charge. Operate the unit on COOL for 5 minutes. If the balls float in the receiver tank sight glass, the R-134a charge level is correct.

  3. If the balls do NOT FLOAT in the receiver tank sight glass after operating the unit on COOL for 5 minutes, the unit is low on R-134a charge. With the unit operating on COOL, add liquid R-134a until the balls FLOAT in the sight glass.

    4. Caution
    • Service procedure
    • When adding R-134a to the unit, STOP adding refrigerant when the balls float near the TOP of the sight glass. Continuing to add refrigerant after the balls float at the top of the sight glass will OVERCHARGE the unit. If necessary, recover refrigerant until the balls no longer float at the top of the sight glass.

R-134a Refrigeration System Receiver Tank

1. Refrigerant charge is OK if the ball floats at any time:

  • If the ball does NOT float, the R-134a refrigeration system is unit is low on refrigerant

    

Parent topic: Checking Refrigerant Charge