NuAire LabGard NU-640-400, Operation And Maintenance Manual

Page: 47 / 56

OM0291 Page 47 of 56
Rev 3 November2020
7.10 Main Control Board Description and 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 one Printed Circuit Board (PCB) assembly.
The PCB contains the power supply, configuration switch, sensor inputs/outputs and control inputs/outputs
components and display.
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 ACCESSORY OUTLET FUSE LIGHT FUSES AUTOLIFT FUSE
FUSE TYPE: TIME-LAG TIME-LAG TIME-LAG TIME-LAG TIME-LAG
FUSE SIZE: 1/4 X 1-1/4 INCH 5 X 20MM 5 X 20MM 5 X 20MM 5 X 20MM
NU-640-400
12 AMPS 3 AMPS 2 AMPS 1 AMP (2) 2 AMPS
NU-640-500 15 AMPS 3 AMPS 2 AMPS 1 AMP (2) 2 AMPS
NU-640-600 15 AMPS 3 AMPS 2 AMPS 1 AMP (2) 2 AMPS
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. blower speed/PWM signal DC voltage setpoints if modified 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 studs/nuts. 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 and 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.
Reconnect power to cabinet.
CAUTION
!
CAUTION
!