NuAire LabGard NU-560-400, Operation & Maintenance Manual

Page: 65 / 103

OM0295
Rev 2 September 2020 Page 65 of 103
7.10 Main Control Board Description & Replacement
To access the main control board for fuse or board replacement, remove screws at each upper side of the control
center and allow the control center to rotate down, resting on the safety straps. Now the main control board is
exposed for service.
7.10.1 Main Control Board Replacement
The main control board consists of two interconnected Printed Circuit Board (PCB) assemblies. The front PCB
contains the LCD display. The back PCB contains the power supply, sensor inputs/outputs and control
inputs/outputs components. The mechanical and electrical interconnects for the two PCB's all occur within the
assemblies and are fastened together with standoffs and screws.
7.10.2 Main Control Board Fuse Replacement
Disconnect electrical power from cabinet before fuse replacement.
All AC circuits are fuse protected and when replacement is necessary, USE ONLY FUSES OF SAME TYPE AND RATING FOR
PROTECTION AGAINST RISK OF FIRE .
DESCRIPTION: BLOWER FUSE OUTLET FUSE LIGHT FUSE
FUSE TYPE: TIME-LAG TIME-LAG TIME-LAG
FUSE SIZE:
1/4 X 1-1/4 INCH 5 X 20MM 5 X 20MM
NU-560-400 10 AMPS 3 AMPS 1 AMP
NU-560-600 10 AMPS 3 AMPS 1 AMP
7.10.3 Main Control Board Replacement
Note: All setup and calibration data will be lost, the memory reinitialized to the default values and all control
functions reset to an initial cabinet power condition. If possible, before the main control board replacement, it
would be preferred to know the operational parameters of the cabinet, (i.e. motor/blower voltage, setpoints, and
airflow data from previous certification.
Disconnect electrical power from the cabinet before
attempting any maintenance action.
The main control board is fastened to the control center with (6) 6-32 screws. All electrical connections are made
with removable terminals and/or Faston connectors except for the motor/blower connector which uses a screw
terminal. Remove all electrical connections and fasteners then remove the main control board from the control
center.
Install new main control board by reattaching all electrical connections and fasteners.
Once installed, rotate control center to normal position and fasten in place.
Now reconnect power to cabinet. Upon BSCC system power up, a system MASTER RESET must be performed to
clear the microprocessors non-volatile memory to assure proper system function.
CAUTION
!