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.

48/50PD

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	Adjust the high temperature lockout setting if it is
			high temperature lockout.	incorrect, otherwise, economizer is operating
				correctly.
			Outdoor---air temperature is below economizer low	Adjust the low temperature lockout setting if it is
			temperature lockout.	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			Minimum position is set incorrectly.	Adjust minimum position setting.
to Minimum Position.
to Minimum Position.			Outdoor---air temperature is above economizer	Adjust the high temperature lockout setting
			high temperature lockout.	if it is incorrect, otherwise, economizer is
				operating correctly.
			Outdoor---air temperature is below economizer	Adjust the low temperature lockout setting
			low temperature lockout.	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			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.
			Damper is jammed.	Identify the obstruction and safely remove.
Economizer Does Not Return			Unit is operating under free cooling.	Economizer is operating correctly.
to Minimum Position.
Damper Does Not Close on Power			Damper is jammed or spring return is backwards.	Identify the obstruction and safely remove.
Loss.				Remove actuator, flip it over and re---install.
Outdoor Damper Does Not Fully Close			Economizer actuator is out of calibration.	Enter Service Test mode and run the Calibrate
at 0% or Fully Open at 100%.				Economizer (E.CAL) procedure.
Economizer is not a configured			Unit is operating under free cooling.	Economizer is operating correctly.
minimum position
minimum position			Unit fan speed is offsetting the economizer minimum	Economizer is operating correctly.
			position to maintain proper ventilation.
LEGEND
CCN	-	Carrier Comfort Network
IAQ	-	Indoor Air Quality
VFD	-	Variable Frequency Drive

48/50PD05 specifications

The Carrier 48/50PD05 is a remarkable addition to Carrier's lineup of rooftop units, offering advanced cooling and heating solutions for commercial applications. Designed for medium-sized buildings, this unit is well-suited for both new installations and as a replacement for older systems, thanks to its versatile features and efficient performance.

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