Carrier 48HC 04-28 Controls, Start-Up, Operation And Troubleshooting page 53

PROBLEM
Damper Does Not Move.
Economizer Operation is Limited to Minimum
Position.
Economizer Position is Less Than Minimum
Position.
Economizer Does Not Return to Minimum
Position.
Damper Does Not Close on Power Loss.
Outdoor Damper Does Not Fully Close at 0%
or Fully Open at 100%.
Economizer is Not at Configured Minimum
Position
LEGEND
CCN — Carrier Comfort Network
IAQ — Indoor Air Quality
Table 18 — Economizer Service Analysis
POSSIBLE CAUSE
Indoor Fan is off.
Actuator is unplugged at motor or at economizer
board.
Unit is not configured for economizer.
Outdoor-air temperature is above economizer
high temperature lockout.
Outdoor-air temperature is below economizer
low temperature lockout.
Communication loss to economizer board.
Damper is jammed.
Minimum position is set incorrectly.
Outdoor-air temperature is above economizer
high temperature lockout.
Outdoor-air temperature is below economizer
low temperature lockout.
Enthalpy or differential dry bulb are preventing
free cooling.
Outdoor-air thermistor is faulty.
Low suction pressure problem with a
compressor.
IAQ is controlling minimum damper position.
Unit is in Unoccupied mode.
Unit is operating under free cooling.
Damper is jammed or spring return is
backwards.
Economizer actuator is out of calibration or
spring return is backwards.
Unit is operating under free cooling or a force is
applied to the commanded position.
53
REMEDY
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.
Check wiring connections.
Configure unit for economizer per the
instructions.
Adjust the high temperature lockout setting if it is
incorrect, otherwise, economizer is operating
correctly.
Adjust the low temperature lockout setting if it is
incorrect, otherwise, economizer is operating
correctly.
Check wiring connections.
Identify the obstruction and safely remove.
Adjust minimum position setting.
Adjust the high temperature lockout setting if it is
incorrect, otherwise, economizer is operating
correctly.
Adjust the low temperature lockout setting if it is
incorrect, otherwise, economizer is operating
correctly.
Check enthalpy and return air compared to
outside air temperature.
Replace outdoor-air thermistor.
Economizer is operating correctly, identify
compressor problem.
Adjust the IAQ settings if incorrect, otherwise,
the economizer is operating correctly.
Adjust unit occupied schedule if incorrect,
otherwise, economizer is operating correctly.
Economizer is operating correctly.
Identify the obstruction and safely remove.
Enter Service Test mode and run the Calibrate
Economizer (E.CAL) procedure.
Economizer is operating correctly.