Model 3600
Refrigerant Recovery System
13
4.5. Liquid Push Pull Recovery Procedures
Liquid push-pull operations are performed by using hot compressor gas to push liquid refrigerant out
of a system. The purge valve accomplishes this by re-directing the hot compressor gas around the
condenser. See the diagram on top of the unit for hose connections.
Step
Description
1
Turn off all electrical or mechanical power to the refrigerant device to be evacuated.
2
Make proper hose connections
. Connect the discharge hose from the outlet port to the low-
pressure side of the system you are servicing. Connect a hose between the liquid port
(receiver or condenser) on the system being serviced and the liquid valve on the DOT
recovery tank. Connect the inlet hose from the DOT recovery tank vapor valve and the unit’s
inlet port. See Figure 3 for hose connection schematic.
NOTE:
You must use an external
filter drier in the suction line in order to meet the conditions of the unit warranty.
Caution:
If the
80% shutoff cord is not used, a scale must be used to monitor the refrigerant level in the
recovery cylinder.
3
Place the inlet and purge valves in the “LIQUID PUSH-PULL” position
. This will allow hot
compressor gas to bypass the condenser. OPEN the liquid and vapor valves on the tank,
(See Figure 4)
4
Open the outlet ball valve and the DOT recovery tank vapor and liquid valves on the
DOT recovery tank
.
5
Turn the system switch to the “ON” position
. When all liquid refrigerant is recovered, turn
the system switch to the “OFF” position.
NOTE:
Liquid push-pull operations do not pull a
vacuum on a system. You must perform a vapor recovery operation in order to pull the system
down to the required vacuum level.
6
Monitor the LED status display
.
LED
Description
Green
SYSTEM ON:
The “SYSTEM ON” indicator should be ON during normal
operations.
No LED
EVACUATION COMPLETE:
Indicates that the unit has shut down because
the system being evacuated has reached 13" HG. (the evacuation is
complete). During liquid push-pull operations the system will not be pulled
into a vacuum.
NOTE:
A small amount of inlet pressure might be needed
to reset the vacuum switch, this is normal.
Red
HIGH PRESSURE:
Indicates that there is a high pressure condition that
must be corrected. Check for restrictions or a full recovery cylinder. Correct
problem and turn system switch to the OFF position. Repeat steps 3-6.
TANK FULL:
Indicates that the recovery cylinder is full (if the 80%
Automatic Tank Full Shutoff Option is installed). Change the recovery
cylinder and repeat steps 3-6.
7
Turn the system switch to the OFF position when all liquid is recovered
. The liquid
recovery operation is complete when the scale or optional sight glass indicates no liquid is
being transferred to the recovery cylinder.
NOTE:
The unit must be manually shut off during
all liquid recovery operations.
8
Proceed to vapor recovery operations to complete the recovery operation
. If the unit is
manually or automatically turned off before the liquid recovery is complete, repeat steps 3-8.
NOTE:
If the circuit breaker trips, wait 10 seconds, reset circuit breaker and go to step 2. If
the compressor thermal overload trips, wait 16 to 30 minutes before restarting.
