Carrier 48/50PD05 - Manual (Page 33)

33
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 11.)
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 5). The
following steps specify how to test the economizer using the
Scrolling Marquee display. See Table 11 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.
Table 11 — Economizer Service Analysis
PROBLEM POSSIBLE CAUSE REMEDY
Damper Does Not Move. Indoor Fan is off. Check for proper VFD connections. Check that
VFD is illuminated and in Auto mode.
Unit is not configured for continuous fan operation
and there are no cooling or heating demands.
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.
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.
Damper is jammed. Identify the obstruction and safely remove.
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.
Remove actuator, flip it over and re---install.
Outdoor Damper Does Not Fully Close
at 0% or Fully Open at 100%.
Economizer actuator is out of calibration. Enter Service Test mode and run the Calibrate
Economizer (E.CAL) procedure.
Economizer is not a configured
minimum position
Unit is operating under free cooling. Economizer is operating correctly.
Unit fan speed is offsetting the economizer minimum
position to maintain proper ventilation.
Economizer is operating correctly.
LEGEND
CCN
-- Carrier Comfort Network
IAQ -- Indoor Air Quality
VFD -- Variable Frequency Drive
48/
50P
D