MAHLE RTI RRC770A - Manual (Page 12)

Page 9
DEEP VACUUM & DEHYDRATION
If the A/C System is "opened" for replacing components, it is important to draw a deep
vacuum on the system before recharging with refrigerant. This vacuuming process not only
removes air from the system, but just as importantly, will remove any moisture in the
system.
A Vacuum Pump in the RRC770 provides the capability of performing this "Deep Vacuum
and Dehydration". The following steps should be followed:
Figure 3 - Deep Vacuum & Dehydration Control Settings
Refer to Figure 3 for the following description of operation.
1. Connect Red and Blue Hoses to the high and low sides of the A/C System.
2. Open Low and High Gauge Valves.
3. Open Red and Blue Hose Valves.
4. Turn Main Power Switch to VACUUM.
5. The Auxiliary Light will illuminate and the RRC770 will start drawing a vacuum which
will be indicated by a dropping pressure on the Low Gauge.
NOTE... If pressure is sensed at the Red and Blue Hoses on the RRC770, the
Vacuum Pump will not start, as this would result in venting of refrigerant. The
Auxiliary Light will not be illuminated to indicate this situation.
If this occurs, turn the Main Power Switch to RECYCLE and the Mode
Selector to
RECYCLE to recover the refrigerant.