Refrigeration (Cont'd)
Electronic Expansion Valve (Optional)
A wide variety of electronic expansion valves and case controllers can be utilized. Please refer to EEV and controller Hussmann’s information sheet. Sensors for electronic expansion valves will be installed on the coil inlet, coil outlet, and in the discharge air. (Some supermarkets require a 4th sensor in the return air). Case controllers will be located in the electrical raceway or under the case.
Expansion Valve Adjustment
Expansion valves must be adjusted to fully feed the evaporator. Before attempting any adjustments, make sure the evaporator is either clear or very lightly covered with frost, and that the fixture is within 10°F of its expected operating temperature.
After case has been brought to running temperature
verify screws along glass clamp aluminum
extrusion are tight.
Measuring the Operating Superheat
1.Determine the suction pressure with an accurate pressure gauge at the evaporator outlet.
2.From a refrigerant pressure temperature chart, determine the saturation temperature at the observed suction pressure.
3.Measure the temperature of the suction gas at the thermostatic remote bulb location.
4.Subtract the saturation temperature obtained in step No. 2 from the temperature measured in step No. 3.
5.The difference is superheat.
6.Set the superheat for 5°F - 7°F.
Thermostat Location
Thermostats are located in the electrical section; behind the rear panel, on the
Wiring Color Code | Electrical |
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The receptacle that is provided on the exterior back of these | ||||
| models is intended for computerized scales with a five amp | |||
| maximum load, not for large motors or other high wattage | |||
| appliances. It should be wired to a dedicated circuit. | |||
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BEFORE SERVICING
ALWAYS DISCONNECT ELECTRICAL
POWER AT THE MAIN DISCONNECT
WHEN SERVICING OR REPLACING ANY
ELECTRICAL COMPONENT.
This includes (but not limited to) Fans, Heaters
Thermostats, and Lights.
CASE MUST BE GROUNDED
NOTE: Refer to label affixed to case to determine the actual configuration as checked in the “TYPE INSTALLED” boxes.
Electrical Circuit Identification
Standard lighting for all models will be full length fluorescent lamps located within the case at the top. The switch controlling the lights, the plug provided for digital scale, and the thermometer are located at the rear of the case mullion.
Field Wiring and Serial Plate Amperage
Field Wiring must be sized for component amperes printed on the serial plate. Actual ampere draw may be less than specified. Field wiring from the refrigeration control panel to the merchandisers is required for refrigeration thermostats. Case amperes are listed on the wiring diagram, but always check the serial plate.
Ballast Location
Ballasts are located within the access panel that runs the length of the rear of the case.
