Nor-Lake Refrigeration Systems - Manual (Page 15)

09/14 Rev. E 101628 15
ELECTRICAL INSTALLATION
Note: All field wiring must be done in accordance with the National Electric Code and/or other
applicable local codes.
a. The field wiring should enter the condensing unit assembly and unit cooler assembly at
locations provided.
b. The specific wiring diagram for each system is located in the plastic bag shipped with the
condensing unit rack that contains warranty information.
c. The available power supply, voltage, frequency, and phase must coincide with the condensing
unit and unit cooler data plate.
d. Before operating, double check all wiring connections including factory terminals. Factory
connections can vibrate loose during shipment.
e. Be certain field wiring is properly sized to handle the connected load.
f. Cold room wall or ceiling wiring penetrations should only be made with UL labeled PVC conduit
or water- tight flexible conduit to avoid condensation on the warm side of the wall or ceiling. The
conduit end must be sealed to prevent moisture migration and the penetration itself must also
be sealed with silicone.
g. On remote rack mounted systems, the room temperature control must be mounted in a location
within the cold room convenient for adjustment and that allows the control cap tube with feeler
bulb to be routed to sense the unit cooler return (inlet) air.
h. The freezer defrost timer must be located near the unit cooler, preferably outside the cold room
in an upright position, unless the system configuration locates it in the condensing unit.
PRE-START CHECK OUT
Prior to final system charging and start-up, the following points must be checked:
1. On accessible hermetic compressors, observe the crankcase oil level. The oil level should be at
or slightly above the center of the sight glass. If oil must be added, use only oil approved by the
compressor manufacturer and suitable for the refrigerant used.
2. Check and adjust the cold room temperature control for the desired operation.
3.
Set the defrost time switch on freezer systems. See the section titled “Defrost Time Switch”.
4. Check and adjust, if needed, the High/Low pressure control. Low side cut-in should be
set at 15-20 pounds, low side cutout at 1-5 pounds, and high-pressure cutout at 440 psi
for R-404A systems.
5. Check to make sure the condenser and unit cooler fan blades rotate without obstruction.
6. Check that all refrigerant tube runs are properly insulated, supported, and that electrical conduit
is properly supported.
7. Make sure cold room wall and ceiling penetrations are properly sealed.
8. Collect all wiring diagrams, instruction manuals, etc. to be filed for future reference.
START-UP AND FINAL REFRIGERANT CHARGE
Before attempting to start the system, make sure that all service valves are open and shipping
blocks have been removed. Unit cooler fans must be operational before attempting to final charge
the system. Note that cooler fans will operate continuously while freezer fans will be delayed by the
fan control until the evaporator is reduced to approximately 25°F.
Scroll compressors are directional, i.e. they will compress in one rotational direction only. On single-
phase compressors this is not an issue since they will always start and run in the proper direction,
except as described in the section “Brief Power Interruptions”. Three phase scrolls, however, will
rotate in either direction depending on the power phasing. Since there is a 50/50 chance of
connected power being backwards, contractors should be warned of this.