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6. Disconnect the vacuum pump, but leave the system under vacuum. Use a charging
scale to accurately weigh in the refrigerant. Charge liquid R-134a refrigerant through
the liquid service valve according to the charge pounds indicated in the "System R-
134a Charge Guidelines" chart below. Additional refrigerant may need to be added,
as detailed in the next step. DO NOT USE REFRIGERANT WITH ADDITIVES.
7. Warm the bottom shell of the compressor above the ambient temperature for 30
minutes to drive excess refrigerant out of the compressor oil. Connect power to the
Evaporator and Condensing unit, and activate the system. Check that the sight glass
is clear when the compressor is running. The condensing temperature must be
above 105°F (135.0 PSIG) when inspecting for a clear sight glass. In a low ambient
environment, it may be necessary to block off the condenser air intake to force the
condensing temperature higher. If the sight glass is not clear, slowly add vapor
refrigerant though the suction service valve.
8. With a clear sight glass, adjust the superheat on the thermostatic expansion valve to
10°F +/- 2°F, as measured at the suction access valve located in the Evaporator.
9. Once the superheat is adjusted, ensure the condenser face airflow is unrestricted
and allow the system to balance for 30 minutes.
10. Check the suction superheat at the compressor using the access port on the suction
service valve. A minimum superheat of 20°F is required at this location. If it is below
20°F, recheck the thermostatic expansion valve superheat and increase as
necessary to ensure a 20°F superheat at the compressor.
11. The fan cycling control (optional) is located in the Condenser Module and is non-
adjustable. The condenser fan cuts-out at approximately 75 PSIG, and cuts-in at
120PSIG. Verify condenser fan operation at startup.
