Refrigerant Recovery

^ ALWAYS RECOVER REFRIGERANT FROM BOTH THE HIGH AND LOW SIDE OF THE VEHICLE'S A/C SYSTEM SIMULTANEOUSLY. This will shorten the recovery process and ensure as much refrigerant as possible is removed from the system.

^ The PureGuard 2 is designed to sample refrigerant vapor from the low side of the vehicle during the recovery process. A pressure switch in the high side is used to sense any attempt to bypass the purity test. If pressure is sensed in the high side only, an "alarm" sounds and recovery is halted. When 30 psi is sensed in the low side, power is restored to the ACR4. Reset of the PureGuard 2 is not necessary and eliminates waiting for the warm-up cycle.

^ There have been reports of the PureGuard 2 being removed from the ACR4 due to a misinterpretation of the red excess air light. The light indicates the presence of high levels of air in the refrigerant storage tank, but it does not stop refrigerant recovery or interfere with the operation of the ACR4. A high percentage of air will increase tank pressure and can slow down or in some cases, stop refrigerant recovery. Excess air should be purged from the tank prior to charging a vehicle. This bulletin includes a procedure for quick elimination of excess air without operating the vacuum or recycle modes.

The red excess air light turns on when the air level measured in the vapor at the top of the tank reaches 6%. When charging a vehicle, liquid refrigerant is drawn from the bottom of the tank which contains a lower percentage of air. As the air content increases, the rise in tank pressure forces air into the liquid refrigerant in the tank. Air in excess of 4% in the vehicle's A/C system can cause concerns.

^ Some GM vehicles have A/C systems that are designed with the low side service port located at a very low spot in the system. Liquid refrigerant will "Puddle" in this location when the A/C system is not operating. If the low side service hose is connected and the recovery process started, a slug of liquid may be delivered to the PureGuard 2. To ensure oil and liquid refrigerant never enter the PureGuard 2, make sure the AFC is installed.