United Technologies Carrier TRANSICOLD 68RM35-604-20 Operation And Service page 29

6. Liquid Line Solenoid Jumper Harness - A
liquid line solenoid jumper harness is used to apply
an external 24 vdc source to energize the
solenoid.
3/8 Flare
Fittings
(4)
Tube
Stock
1--- 1/2
in.
1/4 Flare
Fitting
Figure 4-3. Evacuation Manifold
b. Evacuation Procedure
To help speed up the evacuation process and to
increase the evaporation of moisture, keep the
ambient temperature above 60_F (15.6_C). If
ambient temperature is lower than 60_F (15.6_C),
ice may form before moisture removal is complete.
Heat lamps or alternate sources of heat may be
used to raise system temperature if necessary.
1. Before refrigerant removal and evacuation,
leak test unit.
2. Using an external 24 vdc power source,
energize the liquid line solenoid valve coil by
installing a jumper harness through the
Weatherpac connector.
3. Remove all remaining refrigerant charge in the
system.
4. Connect evacuation manifold, vacuum pump,
vacuum gauge, reclaimer and hoses as shown
in Figure 4-4. All hand valves on manifold
should be closed. The compressor service
valves should be midseated, if used, with
service valve caps installed. The reclaimer
valve should be closed.
5. Start vacuum pump. Slowly open manifold
valve to the pump. Open valve to the vacuum
gauge. Evacuate unit until vacuum gauge
indicates 1500 microns (29.86 inches = 75.8
cm) Hg vacuum. Close gauge valve, vacuum
pump valve, and stop vacuum pump.
6. Open the refrigerant cylinder vapor valve to
break the vacuum. Raise the pressure
approximately 2 psig. This will absorb any
Packless
Valve
1/8 NPT
Fittings
1/8 NPT
Fitting (2)
1/2 Flare
Fitting
Packless
Valve
1/2 Flare Fitting
remaining moisture in the system for the
second evacuation. Close the cylinder valve.
7. Repeat steps 5. and 6.
8. Evacuate again, as described in step 5. to
300--500 microns Hg vacuum.
9. Charge the system to specifications through
the refrigerant recovery machine (using
manufactures charging procedure) or as
outlined in
Refrigeration System).
10. Keep liquid line solenoid valve externally
powered until unit has been charged.
Disconnect external power to the liquid line
solenoid valve before operating unit and
reinstall the Weatherpac to the solenoid coil.
4-5
section 4.8 (Charging the
T-288