Carrier /50HC 04-28, Controls, Start-Up, Operation And Troubleshooting, Page: 53 / 144

53
Table 18 — Economizer Service Analysis
PROBLEM POSSIBLE CAUSE REMEDY
Damper Does Not Move. Indoor Fan is off. Check for proper thermostat connection.
Unit is not configured for continuous fan
operation and the thermostat is not calling for
heating or cooling.
Unit is in Unoccupied mode and there is no call
for heating or cooling.
Tripped circuit breaker.
No power to the unit.
Unit is off via CCN command.
Actuator is unplugged at motor or at economizer
board.
Check wiring connections.
Unit is not configured for economizer. Configure unit for economizer per the
instructions.
Outdoor-air temperature is above economizer
high temperature lockout.
Adjust the high temperature lockout setting if it is
incorrect, otherwise, economizer is operating
correctly.
Outdoor-air temperature is below economizer
low temperature lockout.
Adjust the low temperature lockout setting if it is
incorrect, otherwise, economizer is operating
correctly.
Communication loss to economizer board. Check wiring connections.
Damper is jammed. Identify the obstruction and safely remove.
Economizer Operation is Limited to Minimum
Position.
Minimum position is set incorrectly. Adjust minimum position setting.
Outdoor-air temperature is above economizer
high temperature lockout.
Adjust the high temperature lockout setting if it is
incorrect, otherwise, economizer is operating
correctly.
Outdoor-air temperature is below economizer
low temperature lockout.
Adjust the low temperature lockout setting if it is
incorrect, otherwise, economizer is operating
correctly.
Enthalpy or differential dry bulb are preventing
free cooling.
Check enthalpy and return air compared to
outside air temperature.
Outdoor-air thermistor is faulty. Replace outdoor-air thermistor.
Low suction pressure problem with a
compressor.
Economizer is operating correctly, identify
compressor problem.
Economizer Position is Less Than Minimum
Position.
IAQ is controlling minimum damper position. Adjust the IAQ settings if incorrect, otherwise,
the economizer is operating correctly.
Unit is in Unoccupied mode. Adjust unit occupied schedule if incorrect,
otherwise, economizer is operating correctly.
Economizer Does Not Return to Minimum
Position.
Unit is operating under free cooling. Economizer is operating correctly.
Damper Does Not Close on Power Loss. Damper is jammed or spring return is
backwards.
Identify the obstruction and safely remove.
Outdoor Damper Does Not Fully Close at 0%
or Fully Open at 100%.
Economizer actuator is out of calibration or
spring return is backwards.
Enter Service Test mode and run the Calibrate
Economizer (E.CAL) procedure.
Economizer is Not at Configured Minimum
Position
Unit is operating under free cooling or a force is
applied to the commanded position.
Economizer is operating correctly.
LEGEND
CCN — Carrier Comfort Network
IAQ — Indoor Air Quality