Economizer Troubleshooting
Use the unit Scrolling Marquee display or a CCN device to view the economizer status display and the economizer diagnostic display (see Appendix A) for information on the economizer operation. Check the current alarms and alarm history for any economizer alarm codes and correct any causes. (See Table 12.) Verify any unique control configurations per installed site requirements or accessories. If alarms conditions are corrected and cleared, operation of the economizer may be verified by using the Service Test mode (see Service Test section and Table 4). The following steps specify how to test the economizer using the Scrolling Marquee display. See Table 16 for general economizer service analysis.
1.Enter the Service Test main menu on the display.
2.Enter TEST and turn ON test mode. A password may be needed in order to turn ON the Service Test. The default password is 1111.
3.Return to the main level of Service Test.
4.Enter the INDP submenu and enter an initial value for ECON. This will drive the economizer damper to the specified position. Continue to adjust the ECON value to make sure the economizer opens and closes.
5.Because of a mechanical problem with the economizer, the actuator might acquire a new degree of rotation which is less than M.ANG. If this occurs, a “T414 Economizer Damper Actuator Out of Calibration” alert will be generated. This alert can only occur if the economizer is
using digital communications (Configuration →ECON→E.CTL = 1 or 2). The economizer calibration procedure (Service Test→IND.P→E.CAL) will reconfigure the actuator to the new fully closed and fully open positions. To implement the calibration procedure, change E.CAL from OFF to ON. E.CAL will remain ON as long as the calibration procedure is being implemented (as long as 5 minutes). During the calibration procedure the actuator will close fully and then open fully. After the calibration is complete, the degree of rotation should be greater than M.ANG, causing the T414 alert to clear. If the T414 alert does not clear, check the economizer damper for other mechanical problems.
6.Return to Service Test→TEST and turn OFF test mode. This will cause the unit to return to normal operation.
48/50PG and PM
Table 16 – 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 | Check wiring connections. |
| economizer board. |
|
| Unit is not configured for economizer. | Configure unit for economizer per the |
|
| instructions. |
Economizer Operation is Limited to Minimum Position.
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.
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.
Economizer Position is Less | IAQ is controlling minimum damper position. | Adjust the IAQ settings if incorrect, | ||
Than Minimum Position. |
| 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 | Unit is operating under free cooling. | Economizer is operating correctly. | ||
to Minimum Position. |
|
| ||
Damper Does Not Close on | Damper is jammed or spring return is backwards. | Identify the obstruction and safely remove. | ||
Power Loss. |
|
| ||
Outdoor Damper Does Not Fully | Economizer actuator is out of calibration or spring | Enter Service Test mode and run the Calibrate | ||
Close at 0% or Fully Open at 100%. | return is backwards. | Economizer (E.CAL) procedure. | ||
Economizer is Not at Configured | Unit is operating under free cooling or a force is | Economizer is operating correctly. | ||
Minimum Position | applied to the commanded position. |
| ||
LEGEND |
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|
| |
CCN | - | Carrier Comfort Network |
|
|
IAQ | - | Indoor Air Quality |
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