Carrier 48/50PG C03-14 Operation And Service Manual

Contents

47Economizer TroubleshootingUse the unit Scrolling Marquee display or a CCN device to viewthe economizer status display and the economizer diagnosticdisplay (see Appendix A) for information on the economizeroperation. Check the current alarms and alarm history for anyeconomizer alarm codes and correct any causes. (See Table 12.)Verify any unique control configurations per installed siterequirements or accessories. If alarms conditions are corrected andcleared, operation of the economizer may be verified by using theService Test mode (see Service Test section and Table 4). Thefollowing steps specify how to test the economizer using theScrolling Marquee display. See Table 16 for general economizerservice analysis.1. Enter the Service Test main menu on the display.2. Enter TEST and turn ON test mode. A password may beneeded in order to turn ON the Service Test. The defaultpassword is 1111.3. Return to the main level of Service Test.4. Enter the INDP submenu and enter an initial value forECON. This will drive the economizer damper to thespecified position. Continue to adjust the ECON value tomake sure the economizer opens and closes.5. Because of a mechanical problem with the economizer, theactuator might acquire a new degree of rotation which isless than M.ANG. If this occurs, a “T414 EconomizerDamper Actuator Out of Calibration” alert will begenerated. This alert can only occur if the economizer isusing digital communications (Configuration→ECON→E.CTL = 1 or 2). The economizer calibrationprocedure (Service Test→IND.P→E.CAL) will reconfigurethe actuator to the new fully closed and fully openpositions. To implement the calibration procedure, changeE.CAL from OFF to ON. E.CAL will remain ON as long asthe calibration procedure is being implemented (as long as 5minutes). During the calibration procedure the actuator willclose fully and then open fully. After the calibration iscomplete, the degree of rotation should be greater thanM.ANG, causing the T414 alert to clear. If the T414 alertdoes not clear, check the economizer damper for othermechanical problems.6. Return to Service Test→TEST and turn OFF test mode.This will cause the unit to return to normal operation.Table 16 – Economizer Service AnalysisPROBLEM POSSIBLE CAUSE REMEDYDamper Does Not Move. Indoor Fan is off. Check for proper thermostat connection.Unit is not configured for continuous fanoperation and the thermostat is not calling forheating or cooling.Unit is in Unoccupied mode and there is nocall for heating or cooling.Tripped circuit breaker.No power to the unit.Unit is off via CCN command.Actuator is unplugged at motor or ateconomizer board. Check wiring connections.Unit is not configured for economizer. Configure unit for economizer per theinstructions.Outdoor‐air temperature is above economizerhigh temperature lockout. Adjust the high temperature lockout settingif it is incorrect, otherwise, economizer isoperating correctly.Outdoor‐air temperature is below economizer lowtemperature lockout. Adjust the low temperature lockout settingif it is incorrect, otherwise, economizer isoperating correctly.Communication loss to economizer board. Check wiring connections.Damper is jammed. Identify the obstruction and safely remove.Economizer Operation is Limitedto Minimum Position.Minimum position is set incorrectly. Adjust minimum position setting.Outdoor‐air temperature is above economizerhigh temperature lockout. Adjust the high temperature lockout settingif it is incorrect, otherwise, economizer isoperating correctly.Outdoor‐air temperature is below economizerlow temperature lockout. Adjust the low temperature lockout setting if it isincorrect, otherwise, economizer is operatingcorrectly.Enthalpy or differential dry bulb are preventing freecooling. Check enthalpy and return air compared tooutside air temperature.Outdoor‐air thermistor is faulty. Replace outdoor‐air thermistor.Low suction pressure problem with a compressor. Economizer is operating correctly, identifycompressor problem.Economizer Position is LessThan 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 Returnto Minimum Position. Unit is operating under free cooling. Economizer is operating correctly.Damper Does Not Close onPower Loss. Damper is jammed or spring return is backwards. Identify the obstruction and safely remove.Outdoor Damper Does Not FullyClose at 0% or Fully Open at 100%. Economizer actuator is out of calibration or springreturn is backwards. Enter Service Test mode and run the CalibrateEconomizer (E.CAL) procedure.Economizer is Not at ConfiguredMinimum Position Unit is operating under free cooling or a force isapplied to the commanded position. Economizer is operating correctly.LEGENDCCN - Carrier Comfort NetworkIAQ - Indoor Air Quality48/50PG and PM