Chapter 9 - Refrigerants
5. Run the vacuum pump for at least an hour to remove the moisture
from the system.
The moisture must turn to gas before the pump can pull it out. The moisture
takes time to boil away, so that it can be drawn out of the system.
Your vacuum pump can draw most of the air out pretty quickly. But a
deep vacuum requires more time; the deeper the vacuum the longer it takes
to get there. To ensure the least possible amount of air and moisture in the
system, buy a good quality vacuum pump, take care of it, and use it for at
least an hour.
Figure 9-4
Vacuum Pump.
WARNING
Lubricants removed during the recovery process must be
replaced with new lubricants.
Charging the AC system
*Use a charging station whenever possible.
When adding a full charge of refrigerant, you can put it in as a gas or as a
liquid. Adding refrigerant as a liquid is faster but can damage the
compressor if not done correctly. The procedure you use, and where you add
the refrigerant in the AC system makes a difference. When using refrigerant
as a liquid, never add more than two thirds of system requirements as a
liquid. Finish charging the system using gas. Always keep the refrigerant
containers in an upright position so that no liquid is drawn into the system.
Refer to the Charging with Refrigerant Gas section below for the
procedure for gas charging. Refer to the Charging the System with Liquid
Refrigerant section for the procedure for liquid charging.
Charging with Refrigerant Gas (on the Low Side)
Perform this procedure to charge with refrigerant gas:
1. Use a charging meter or station to select the exact amount of refrigerant
required. Never add more than the amount of refrigerant recommended
by the manufacturer (in pounds and ounces). To measure, use a
container and scale, or charging station.
9-8
