A/C System Evacuation

Special Tools Required

Image	Description/Tool Number
	Compact Electronic Vacuum Gauge Robinair ROB14777*, commercially available

*Available through the Honda Tool and Equipment Program; call 888-424-6857

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.

NOTE:

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 compact electronic vacuum gauge may decrease the required evacuation time because you can measure actual moisture level with this tool.

A more efficient way to measure moisture removal is with a special tool called a compact electronic vacuum gauge, measuring vacuum levels in microns.

Connect the tool according to the manufacturers instructions and allow the vacuum pump to run until the gauge reads 500 microns.

Shut off and isolate the vacuum pump, then observe the gauge reading:

If the vacuum level remains stable at 500 microns for at least three minutes, all moisture in the system has been removed.

A slow increase in the micron reading means there is still moisture boiling out of the system. Restart the vacuum pump and continue evacuating.

A quick increase of micron levels indicates a leak is present in the system or your service equipment. Determine the cause and correct the leak before continuing.

When an A/C System has been opened to the atmosphere, such as during installation or repair, it must be evacuated using an R-134a refrigerant recovery/recycling/charging station. If the system has been open for several days, replace the receiver/dryer, drain the refrigerant oil, and add fresh oil. Then evacuate the system for several hours before charging it.

1.	R-134a Refrigerant Recovery/Recycling/Charging Station - Connect

Connect an R-134a refrigerant recovery/recycling/charging station (A) to the high-pressure service port (B) and the low-pressure service port (C), as shown, following the equipment manufacturer's instructions.

2.	A/C Refrigerant - Recover

Recover the refrigerant from the A/C system.

Measure the amount of refrigerant oil removed from the A/C system after the recovery process is completed. Be sure to put the same amount of new refrigerant oil back into the A/C system before charging.

3.	A/C System - Evacuate

Evacuate the system. The vacuum pump should run for a minimum of 30 minutes 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, close all valves, and turn off the vacuum pump.

If the suction gauge dose not reach approximately ?93.3 kPa (?700 mmHg, ?27.55 inHg) in 15 minutes, there is probably a large leak in the system. Partially charge the system, and check for leaks.