Evacuate System

WITH VACUUM PUMP
Vacuum pumps suitable for removing air and moisture from A/C systems are commercially available. The pump should be capable of drawing the system down to 28-29 inches Hg at sea level. For each 1000 foot increase in altitude, this specification should be decreased by 1 inch Hg. As an example, at 5000 feet elevation, only 23-24 inches Hg can be obtained.

1. Connect suitable gauge manifold and discharge system as outlined previously. System must be completely discharged prior to evacuation. If pressurized refrigerant is allowed to enter vacuum pump, pump will be damaged.
2. Connect hose from gauge manifold center port to vacuum pump inlet.
3. Fully open both gauge manifold hand valves.
4. Operate vacuum pump while observing low side compound gauge. If system does not pump-down to 28-29 inches Hg (at sea level) within approximately 5 minutes, recheck connections and leak test system.
5. Continue to operate vacuum pump for 15-30 minutes, longer if system was open for an extended period of time, then close both manifold valves and stop pump.
6. Check ability of system to hold vacuum. Watch low side compound gauge and ensure reading does not rise at a rate faster than 1 inch Hg every 4-5 minutes.
7. If system fails to hold vacuum, recheck fittings and connections, and leak test system.
8. If system holds vacuum, charge system with refrigerant.

WITH CHARGING STATION
A vacuum pump is built into the charging station that is constructed to withstand repeated and prolonged use without damage. Complete moisture removal from the A/C system is possible only with a pump of this type.

1. Connect charging station No. J-23500-01 or equivalent, then discharge system as outlined previously. System must be completely discharged prior to evacuation. If pressurized refrigerant is allowed to enter vacuum pump, pump will be damaged.
2. Reconnect vacuum hose to vacuum pump and ensure vacuum control valve is closed.
3. Fully open low pressure control valve only.
4. Connect station to a suitable voltage source and operate vacuum pump.
5. Slowly open vacuum control valve and observe low side compound gauge. If system does not pump down to 28 to 29-1/2 inches Hg (at sea level) within approximately 5 minutes, recheck connections and leak test system.
6. Continue to operate vacuum pump for 15-30 minutes, longer if system was open for an extended period of time, then close all control valves and stop pump.
7. Check ability of system to hold vacuum. Watch low side compound gauge and ensure reading does not rise at a rate faster than 1 inch Hg every 4-5 minutes.
8. If system fails to hold vacuum, recheck fittings and connections, and leak test system.
9. If system holds vacuum, charge system with refrigerant.