Line Sizing
Refrigerant lines should be sized as shown on the refrigeration legend that is furnished for the store or according to ASHRAE guidelines. Refer to the information on the next page for branch line piping of Hussmann Equipment.
Oil Traps
Pressure Drop
Pressure drop can rob the system of capacity. To keep the pressure drop to a minimum, keep the refrigerant line run as short as possible using a minimum number of elbows. Where
elbows are required, USE LONG RADIUS ELBOWS ONLY.
INSULATION
The suction and liquid lines should be clamped or taped together and insulated for a minimum of 30 ft (9144 mm) from the merchandiser.
Additional insulation for the balance of the liquid and suction lines is recommended wher- ever condensation drippage is objectionable or lines are exposed to ambient conditions.
SUCTION LINE
•Pitch in direction of flow.
•May be reduced by one size at one third of case run load and again after the second third. Do not reduce below the case suction line size.
•Case suction lines should enter at the top of the branch line.
Suction Line Return
LIQUID LINE
•May be reduced by one size after one half the case run load. Do not reduce below the case liquid line connection size.
•
Minimum Loop
Liquid Line Take Off
CONTROL SETTINGS
Merchandiser Technical Data Sheets (TDS) are shipped with this manual. The TDS provide case control settings and defrost data.
An evaporator pressure regulator or EPR (primary control) and a 3 – 5ºF (1.7 – 2.7ºC) differential thermostat (secondary control) must control refrigeration temperature. The EPR must be set to maintain the proper saturated evaporator temperature as listed in the data sheets. The thermostat must be set a couple degrees colder than the discharge air tempera- ture specified in the data sheets. The thermostat will prevent product freezing should the EPR temperature drift downward during reduced load periods (lights off, lower ambient). The thermostat will be wired to control the com- pressor motor contactor (single compressor) or a liquid line solenoid valve (parallel compressor systems).
Defrost is Off Time. Defrost control settings are listed in the data sheets. When these merchan- disers are connected to parallel compressor systems, a suction stop valve must be used to isolate the evaporator during defrost periods.
P/N 0420057_B | U.S. & Canada |
