Installation, Start-Up, Adjustment and Maintenance Manual
65
12 APPENDIX
ELECTRONIC CONTROL BOARD (S-60)
All chiller functions and operations are monitored and controlled by the electronic control board.
When power is supplied to the unit, the electronic control board will initialize the control program.
“
CAP
” will appear on the display. “
H60
” will appear next, showing that the power supply to the board is
60 hertz. The display will next show the chilled water thermostat set point.
The board will then begin to monitor all thermistors and switches to ensure proper and normal working
conditions. If a fault occurs with any of the thermistors and switches, a fault code will appear (see
Fault Codes on page 59).
If no faults are found and the control switch wired to the R-Y contacts is closed, the electronic control
board will start the unit. The hydraulic pump, condenser fan, and water pump (if controlled by the unit)
will start. Simultaneously, the electronic control board will energize the ignition control box to begin the
ignition sequence (see Ignition Control Box for details).
During operation, the inlet water temperature and temperature differential will appear on the display,
indicated respectively by different LEDs (see Section 6.5, Chilled Water Temperature Regulation).
The electronic control board will increase or decrease the condenser fan speed to obtain the designed
temperature differential between the external ambient and the condenser outlet. If this maximum
allowable temperature differential is not maintained, a fault code will appear (see Page 59, Fault
Codes).
If the control switch is opened, the S-60 board will de-energize the ignition control box and begin cycle
down. The hydraulic pump, condenser fan, and water pump (if controlled by the unit) will continue to
operate for another 215 seconds.
If the chilled water thermostat set point is reached, the S650 board will de-energize the ignition control
box and begin cycle down. The hydraulic pump and condenser fan will continue to operate for another
215 seconds. The water pump (if controlled from the S-60) will continue to run until the outlet water
temperature is 1
F above the chilled water set point. If the control switch is still closed, the unit will
start again.
The electronic control board has three 5mm x 20mm fuses for circuit protection. If the electronic control
board does not start up or the condenser fan does not run, remove power from the unit and check the
condition of the fuses. The S-60 board requires a 10A, 3.15A, and 2A fuse. The size of the fuse is
labeled on the electronic control board next to the respective fuse holder (see Figure 41).
The
maximum
current carrying capacity of th
e N.O. C
ontact is
4A.
.
An isolation relay
MUST
be used to separate the unit’s transformer from additional equipment having a
transformer or damage to the S-60 board will occur. Refer to Section 5.3, Control Switch Wiring. Relay
(Kit No. 18010-116)
NOTE
WARNING
WARNING
