CSR-20 & CSR-40, September 1999
Unit Wiring
Inspect unit wiring, wire harnesses, and the controller during
pre-trip inspection and every 1,000 operating hours to protect
against unit malfunctions due to open or short circuits. Look
for loose, chaffed or broken wires on the unit; open or short
circuits and damaged components on the controller printed cir-
cuit board.
Inspect electrical contactor points for pitting or corrosion
every 1,000 operating hours. Repair or replace as necessary.
Auxiliary Battery and Battery Charger
(Option)
An auxiliary battery is available to operate the
µ
P-D controller
when the unit is not connected to a 460-380 Vac power supply.
Pressing the controller SELECT key provides battery power to
the controller for 5 minutes to allow setpoint adjustment or a
download of the datalogger. The battery box is mounted in the
cord storage compartment.
Check the battery voltage during the unit pretrip inspec-
tion. The battery is a 12 Vdc, 7 or 12 Amp hour Gel Cell. The
voltage should be 12.4 to 12.7 Vdc. If the voltage is 11.5 to
12.39 Vdc, the battery must be charged. Charge the battery
until the current into the battery at 13.6 Vdc @ 25 C (77 F) is
less than 10 mA. If the voltage is less than 11.5 Vdc, replace
the battery.
NOTE: The battery charging current MUST NOT
exceed 800 mA.
If the battery is undercharged, check the battery charger
for proper operation.
High Pressure Cutout Switch
The high pressure cutout is located in the liquid line near the
compressor. If the discharge pressure rises above 3243 +/- 48
kPa, 32.43 +/- 0.48 bar, 470 +/- 7 psig, the switch opens the
R51A circuit:
• The compressor and evaporator fans STOP immediately.
• The condenser fan will continue to operate.
• After 5 minutes, the controller attempts to restart the
compressor.
• If the compressor restarts and operates for 10 minutes
without an overload condition, no alarm is recorded.
• If the overload still exists after 5 minutes, the controller
turns the Alarm LED ON. Also, if the overload condi-
tion occurs 3 times within 30 minutes, an alarm is
recorded. Pressing the ALARM key on the controller
will cause alarm code 10 (High Refrigerant Cutout) to
appear on the right display.
• Unit restarts when the overload condition is corrected
(reset) as long as power is available.
Checking for an Open High Pressure Cutout Switch
NOTE: This procedure check for a defective high
pressure cutout switch that is stuck open.
If the unit stops due to high pressure cutout and does not
restart, check the following:
1.
Lower the condenser pressure by operating the condenser
fan for 10 minutes. Use the AMPS/CFH (high speed con-
denser fan) test from the Test Menu of the
µ
P-D con-
troller. After several minutes, the high discharge pressure
condition should correct itself and the high pressure cutout
switch should close (reset). The compressor should restart
as long as power is available.
5
Electrical Maintenance
