Refrigeration - Operation Set Points • 23
REfRIgERATION
Operation Set Points
Refer to the case spec sheet for btu/h requirements and electrical requirements. Operate the case at the following settings to maintain product
temperature of 41°F or below, per food safety regulations (
Defrost
Crystal Merchandiser
®
coolers can be set up with either off-cycle defrost or electric defrost.
for defrost settings.
Case Thermometers
The cases are shipped with 2 thermometers. One thermometer is factory-mounted to sense the discharge air stream (rear duct). A second NSF
thermometer is shipped loose and should be installed in the warmest product location as required by NSF. Specific field installation instructions
are packaged with the NSF thermometer.
SETTING
COOLER
Defrost Type
Off-Cycle
Electric
Frequency
3 Per Day
2 Per Day
Duration
45 Minutes
30 Minutes
FIGURE 34: Defrost Settings
FIGURE 33: Case Temperature Internal Control Options
SETTING
COOLER
Evaporator Temp
28°F
Return Air Temperature Set Point
33°F
Return Air Temperature Differential
4°F
Discharge Air Temperature Set Point
30°F
Discharge Air Temperature Differential
4°F
SETTING
R-404A
R-448A Sat. Temp
Condensing Unit Cut-In
74 psig
62 psig
33°F
Condensing Unit Cut-Out
62 psig
51 psig
25°F
Note: Set points based on superheat of 6-8°F.
For high-glide refrigerants,
use dew point for unit sizing. Adjust evaporator pressure as needed to maintain
discharge air temperature. To receive the full benefit of high-glide refrigerant
properties, the superheat may need to be lowered to 4-6°F. Contact Zero Zone
with questions.
