High Side Repair; Adding Refrigerant - Trane RTAA-70 Installation & Maintenance Manual

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Refrigerant Charging and Recovery
10. Open all valves, start the unit and verify the refrigerant charge by
measuring the subcooling.

High Side Repair

If the refrigerant needs to be isolated in the low side of the unit, perform the
following procedures:
1. Press the STOP key and send the unit through a stopping mode.
2. Close the discharge service valve.
3. Before closing the liquid line service valve, attach a manifold gauge set to
the liquid line valve backseat port.
4. Close the liquid line service valve.
5. Attach the inlet of a liquid transfer pump to the manifold gauge set and
the outlet to the 1/4" angle valve, located between the EXV and the evap-
orator. This will transfer the liquid refrigerant.
6. Remove the liquid transfer pump. Attach the inlet of a recovery system to
the manifold gauge set and the outlet to the 1/4" angle valve, located
between the EXV and the evaporator. Remove all of the vapor from the
high side of the system.
7. Complete all necessary repairs.
8. Evacuate the high side through the access port on the liquid line service
valve that has the manifold gauge set attached to it.
9. Open all of the valves and run the unit. Verify the refrigerant charge by
measuring the subcooling and monitor the sightglass.

Adding Refrigerant

If the entire charge has been removed, perform the following procedures to
recharge the unit:
1. Open all service valves.
2. Establish water flow through the evaporator. Connect a hose from the
refrigerant bottle to the backseat port on the liquid line shutoff valve.
Midseat the valve.
CAUTION
Freezing and Rupturing Tubes Damage!
The evaporator water flow needs to be established and
maintained while adjusting the charge to avoid freezing and
rupturing the tubes. Refrigerant pressure below 65 psig can also
cause freezing and rupturing of the evaporator tubes.
3. It may not be possible to put the entire amount of the refrigerant charge
required using Step 2. If so, start the unit and add liquid refrigerant
through the 1/4" liquid line angle valve between the EXV and the
evaporator.
4. Once the unit has been charged with refrigerant, start the unit. Measure
the subcooling and monitor the sightglass to verify that the refrigerant
charge is correct.
RTAA-SVX01A-EN