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RTAC-SVX01F-EN 157
Maintenance Procedures
2. Attach charging hose to evaporator service valve (3/8” (9mm) flare). Open service
valve.
3. Add charge to evaporator to bring total circuit charge up to the level indicated in
the above chart.
4. Close service valve and disconnect charging hose.
Adding charge:
This procedure should be followed when adding charge to an undercharged unit.
When low charge is indicated by low subcooling in the liquid line, charge should be
added until sufficient subcooling is achieved.
1. Attach charging hose to evaporator service valve (3/8” (9mm) flare). Open service
valve.
2. Add 10 pounds of refrigerant (R-134a) charge.
3. Close valve, remove charging hose and start unit. Monitor subcooling.
4. If subcooling is still insufficient, return to step #1.
NOTE: Proper subcooling can be determined from run log history, service
experience, or by contacting Trane technical service.
Charge Isolation in the high or low side of system
All the refrigerant may be trapped into the high side (condenser) of the unit for main-
tenance on the compressor or low side. With the suction line service valve option,
charge may also be isolated in the evaporator for maintenance on the compressor or
the high side. It is preferable to isolate the charge in the evaporator, if this option is
available.
High side charge isolation procedure:
1. Make sure circuit is off.
2. Shut liquid line service valve.
3. Shut oil return line service valve.
4. Start circuit with the service tool in charge isolation mode:
– All fans will turn on
– EXV will open 100%
– Oil return line solenoid (if included) will open
– Unit will start at minimum load
– Unit will run until it cuts out on low pressure (~6 psia) (0.41 bar)
– Monitor pressure with a suction gauge
5. When unit trips, the discharge check valve will close.
6. Close discharge isolation valve.
7. Close oil line shut off valve.
8. Remove the remainder of the charge with transfer pump.
NOTE: Recommendation: Do not pump remaining charge into high side. This may
introduce non condensable gasses and other contaminants into the unit.
9. The low side and compressor may be serviced at this time.