CSR-20 & CSR-40, September 1999
µ
P-D Controller
Alarm Codes, Descriptions and Corrective Actions
4-59
Code
Description
Corrective Action
56
Low Speed Evaporator Fan Failure
• Check for low supply power voltage.
(Pretrip) (Check or Shutdown Alarm)
• Check low speed evaporator fan current draw
• Indicates evaporator fan current draw is not
using “AMPS EFL” in the Electrical Test submenu.
within acceptable limits when fans are in
Current draw should be 0.8 to 2 amperes at 480V
high speed.
for 3 fans. Current draw on each leg should be
within 0.2 amperes of each other.
• Controller also generates alarm if cooling
capacity is not sufficient.
• If current draw is high, check evaporator fan motors
for free rotation and proper condition. Check
• If alarm occurs during a Pretrip test, a
direction of fan rotation (counterclockwise) as shown
dash (-) precedes the alarm code.
by directional arrows. Check for obstructions to
evaporator airflow.
• Visually inspect evaporator fan low speed
contactor.
• If contactor does not energize, check output module
using “AMPS EFH” in the Electrical Test submenu.
Then confirm that output LED AC8 is ON.
• If current draw on each leg is not within 0.2 amperes
of each other during current draw test, check the
current transformer. Turn unit OFF and disconnect
power supply. Disconnect plug on current trans-
former and check the resistance of each primary
winding. Resistance for each winding should be 43
+/- 0.5 ohms.
• Check refrigeration system for obstructions or low
refrigerant charge.
