Wine-Mate SSHWC Series - Manual (Page 24)

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3) The subcooling at the condensing unit shall be around 10°F. The charge may
be complete when there are no more bubbles forming in the liquid indicator.
4) Head pressure is maintained constant but will vary with the water outlet
temperature: 120 ~ 190 psig at the water outlet temperature 95 ~ 120 °F.
5) The evaporator’s constant pressure expansion valve is set around 30 ~ 35
psig (35 ~ 40°F) at factory. This pressure setting gives a dew point to
maintain the proper humidity for storing wine.
6) The temperature split across the evaporator shall be 8 ~ 10°F at 55°F wine
cellar temperature.
7) Again, you must verify if the superheat at the evaporator unit is around 9 ~
18°F at 55 °F ~ high wine cellar temperatures.
8) If the superheat is high, check the subcooling first to know if the refrigerant
charge is sufficient. If the charge is not sufficient, add more refrigerant. If the
charge is good, then increase the evaporator suction pressure by turning the
hex nut (5/16”) clockwise. Liquid must always be charged into the hide side
when the compressor runs.
9) If the superheat is low, then decrease the evaporator suction pressure by
turning the hex nut (5/16”) counter-clockwise.
10) Both discharge and suction valves must be in the back positions before
disconnecting.
11) Close all service valves and disconnect all manifolds and hoses.
Fig. 13 Expansion Valve
11. Pressure, Superheat and Subcooling Readings
CAUTION:
To read properly the service valves must be in the middle positions.
Complaint Possible Causes
1) High suction pressure and low head pressure
Zero superheat and zero subcooling
2) High suction pressure and low head pressure
Low superheat and low subcooling
3) High suction pressure and high head pressure
Low superheat and high subcooling
4) High to normal suction pressure and high head pressure 1) Compressor may be bad
2) Expansion valve opened, too
much oil
3) Overcharge
4) Non-condensable
gas