Refrigeration • 21
REFRIgERATION
Refrigeration risers should be sized to maintain proper refrigerant velocity and oil return. Zero Zone recommends one riser per refrigeration
circuit on circuits utilizing hot gas defrost. Field piping must be 3" away from the defrost heater element on cases utilizing electric defrost.
The end frames on the cases have cut-outs built into them to allow for case-to-case field piping.
When multiple case sections are connected to a single compressor, the main liquid and suction line for the group should be run through the
cases and be brought out through the refrigeration outlet of a single case only. The factory recommends 1 riser per circuit/system for hot gas
defrost when using top back refrigeration exit. The end frames on the cases have cut-outs built into them to allow for case-to-case field piping.
After connections have been made, the refrigeration access hole in the case must be sealed completely with an aerosol-dispensed urethane
insulation or equivalent (example: Great Stuff). Penetrations made in sheet metal baffles should also be sealed (
Cases will be equipped with a liquid-line filter drier by default.
Leak Check, Evacuation, & Charging
After all of the refrigeration piping and system components have been assembled, the entire system must be pressurized and checked for leaks.
When the system is leak free, evacuate with a deep vacuum pump. Triple evacuation should be done to 500 microns or less, and nitrogen
sweep is recommended. After the system has been thoroughly evacuated of all moisture and non-condensable gas, charge the system with the
specified refrigerant.
Operation Set Points
Refer to the case spec sheet for btu/h requirements and electrical requirements. Customers may operate their cases based on a variety of set
points, including evaporator temp, return air, discharge air, or condensing unit pressure. Operate the case at the following settings to maintain
correct product temperature (
). The settings are approximate due to variations in gauge accuracy, differences in
compressor efficiency, line pressure drop, and superheat settings. Before making adjustments for store or stocking conditions, make sure the
superheat is set. Close coupled systems typically run at the higher end of this range to avoid flood back. For Hybrid
™
cases, please refer to the
Hybrid
™
Installation & Operation Manual.
FIGURE 35: Penetration Sealing
