A/C Refrigerant Recovery/Evacuation/Charging: Procedure

WARNING:

Compressed air mixed with the HFO-1234yf (R-1234yf) forms a combustible vapor.
The vapor can burn or explode causing serious injury.
Never use compressed air to pressure test HFO-1234yf (R-1234yf) service equipment or vehicle air conditioning systems.

WARNING:

Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat.
Be careful when connecting service equipment.
Do not breathe refrigerant or vapor.

NOTICE:

If accidental system discharge occurs, ventilate the work area before resuming service.
Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.
Do not allow moisture to contaminate the A/C system oil. Moisture in the oil is difficult to remove, and it can damage the A/C compressor.
Using a thermistor (compact electronic) vacuum gauge may decrease the required evacuation time because you can measure actual moisture level with this tool.
Connect an A/C recover/recycle/recharge machine, following equipment manufacturer's instructions.

When an A/C System has been opened to the atmosphere, such as during installation or repair, it must be evacuated using an A/C recover/recycle/recharge machine. If the system has been open for several days, replace the receiver/dryer or the desiccant, drain the refrigerant oil - Refer to: A/C Refrigerant Oil Replacement or A/C Refrigerant Oil Adjustment , and add fresh oil. Then evacuate the system for several hours before charging it.

A/C Refrigerant - Recover
Procedure

1. Recover the refrigerant from the A/C system.

2. Measure the amount of refrigerant oil - Refer to: A/C Refrigerant Oil Replacement or A/C Refrigerant Oil Adjustment

removed from the A/C system after the recovery process is completed. Be sure to put the same amount of new refrigerant oil - Refer to: A/C Refrigerant Oil Replacement or A/C Refrigerant Oil Adjustment back into the A/C system before charging.
A/C System - Evacuate
Procedure/Specifications

1. Evacuate the system. The vacuum pump should run for a minimum of 30 minutes or until the moisture vacuum test passes, to eliminate all moisture from the system. When the suction gauge reads -93.3 kPa (-700 mmHg, -27.55 inHg) for at least 30 minutes, or the moisture vacuum test passes, close all valves, and turn off the vacuum pump.

2. If the suction gauge does not reach approximately -93.3 kPa (-700 mmHg, -27.55 inHg) in 15 minutes, the moisture vacuum test fails, there is probably a leak in the system. Partially charge the system, and check for leaks.

A/C Refrigerant - Charge

Procedure/Specifications

Charge the system with the specified amount. Do not overcharge the system; the A/C compressor will be damaged.

Select the appropriate units of measure for your refrigerant A/C recover/recycle/recharge machine.

Refrigerant Capacity

Type	Specified Amount
HFO-1234yf (R-1234yf)	505 to 555 g
	17.81 to 19.58 oz
	0.505 to 0.555 kg
	1.113 to 1.224 lbs

After Charging

A/C Refrigerant Leak Check
A/C System Test - Refer to: A/C System Contamination Inspection or A/C System Test or A/C System Inspection