4-48
Alarm Codes, Descriptions and Corrective Actions
µ
P-D Controller
CSR-20 & CSR-40, September 1999
Code
Description
Corrective Action
06
Humidity Sensor Error
• Check the sensor by selecting it using the View
(Check Alarm)
menu. If the display shows [- - - -], the sensor is
defective or the circuit is open or shorted.
• Indicates a problem exists with this sensor or
its wiring. The sensor is reading out-of-
• Check the sensor by substitution. Be sure the sen-
range; or appears to be open or shorted.
sor polarity is correct.
• Continuity check circuit wiring using a high quality
ohmmeter. Be sure to maintain the correct polarity.
NOTE: Do NOT use a test light or other instru-
ment; or controller damage may result.
07
Return Air Temperature Sensor Failure
• Check the sensor by selecting it using the RET/SUP
(Check Alarm)
key (if necessary). If the display shows [- - - -], the
sensor is defective or the circuit is open or shorted.
• Indicates a problem exists with this sensor
or its wiring. The sensor is reading out-of-
• Check sensor by substitution. Be sure sensor
range; or appears to be open or shorted.
polarity is correct. Replacement sensor MUST be
calibrated or sensor grade set.
• Sensor Check test detected an out-of-range
condition.
• Continuity check circuit wiring using a high quality
multimeter. Be sure to maintain the correct polarity
• This sensor REQUIRES ice bath calibration or
or the sensor will not work
.
correct sensor grade setup.
NOTE: Do NOT use a test light or other
NOTE: If the Return Air sensor is the
instrument; or controller damage may result.
controlling sensor when it fails, the
controller continues unit operation
using the Supply Air sensor.
09
Evaporator Coil Over Temperature
• Check electric heater rod operation using the
(Shutdown Alarm — prevents unit from
“AMPS HEATR” test in the Electrical Test submenu.
operating in Heat or Defrost)
• Check evaporator coil sensor using View Menu.
• Evaporator coil has exceeded high
temperature limit.
• Check airflow over evaporator coil.
