Carrier 48/50PD05 User Manual

Page 27

Recovery is automatic but MBB board replacement may be
necessary. Cycling the power to the control should be tried before

board replacement.
Alarm Code T155 -- Serial EEPROM Storage Failure Error
Configuration data in the serial EEPROM chip can not be verified.
The unit will run to last know good values or defaults, and

therefore operating errors may occur. Recovery is automatic but

MBB board replacement may be necessary. Cycling power to the
control and reconfiguring the control points should be tried before

board replacement.
Alarm Code A156 -- Critical Serial EEPROM Storage Fail
Error
The unit will completely shut down. Critical configuration data in

the serial EEPROM chip can not be verified. Recovery is automatic
but MBB board replacement may be necessary. Cycling power to

the control and reconfiguring the critical control points should be
tried before board replacement. There are no critical configurations

in the 48/50PD.
Alert Code A157 -- A/D Hardware Failure
The unit will completely shut down. The analog to digital
conversion chip on the MBB has failed. Recovery is automatic but

MBB board replacement may be necessary. Cycling power to the

control should be tried before board replacement.
Alert Code A163 -- Circuit A Down due to Failure
This alarm occurs when a circuit has 3 strikes. Use the Scrolling
Marquee display to reset the alarm. Investigate the alarm that

caused the strikes to occur.
Alert Code T178 -- Loss of Communication with the Capacity
Control Board
This alert occurs when the MBB cannot communicate with the

AUX1 board. Unit operation will be disabled. This is usually
caused by a wiring problem. Investigate using the Low Voltage

Schematic, check that the AUX1 address is correct, and verify the
resistance between pins on the LEN connections.
Alert Code T179 -- Loss of Communication with the
Economizer Control Board
This alert occurs when the MBB cannot communicate with the
ECB. Economizer operation will be disabled. This is usually

caused by a wiring problem. If a relative humidity sensor is
installed and configured but there is not an ECB installed on the

unit, this alert will be generated (the ECB is required for RH sensor

operation). Investigate using the Low Voltage Schematic, check
that the ECB address is correct, and verify the resistance between

pins on the LEN connections.
Alert Code T180 -- Loss of Communication with the
Economizer Actuator
This alert occurs when the ECB cannot communicate with the

Belimo Actuator. If the analog signal is connected properly, the
economizer will still be controlled through it. This is usually

caused by a wiring problem, actuator failure, or the wrong actuator.
Investigate using the Low Voltage Schematic, make sure the

actuator is a MFT communication actuator, and verify the feedback

signal from the actuator is correct.
Alarm Code A200 -- Linkage Timeout -- Comm Failure
This alarm occurs when the MBB fails to communicate with a

Linkage device. This only occurs when the MBB has previously

communicated with a Linkage device since last power cycle. If a
back up sensor was not installed the T074 alert will occur shortly

after this one. Reset power to the unit and verify Linkage is
communicating.
Alarm Code A404 -- Fire Shutdown
This alarm occurs when the shutdown input is either open or

closed depending upon its configuration. This alarm is usually

caused by an auxiliary device that is trying to shut down the unit,
e.g., smoke detector. The configuration for this switch input can be

found at variable Configuration→UNIT→FS.SW. Verify that the

configuration is set correct, verify the wiring and auxiliary device.

This alarm resets automatically.
Alert Code T408 -- Dirty Air Filter
This alert occurs when the Filter Status switch senses a plugged
filter for 120 continuous seconds after the indoor fan has been

running for 10 seconds. Because the Dirty Air Filter switch can be

configured normally opened or closed, the switch might be open or
closed. The configuration for this switch input can be found at

variable

Configuration→UNIT→FL.SW. Verify

that

the

configuration is set correct and verify the wiring and filter status

switch. The hose should be connected to the low side of the switch.

This alert resets automatically.
Alert Code T409
There are 2 different texts for this alert code. Pressing enter and esc

on the marquee or navigator to expand the T409 alert will show

you one of the below alerts. Make sure the expanded text is read
correctly before troubleshooting.

Fan Status Switch On, Fan Contactor Off
This alarm occurs when the fan status switch has sensed that the
indoor fan has been on for 10 seconds and the indoor fan
feedback has determined that the indoor fan should be off.
Because the Fan Status switch can be configured normally
opened or closed, the switch might be open or closed. The
configuration for this switch input can be found at
Configuration→UNIT→FN.SW. Verify that the configuration
is set correctly. Verify the wiring and fan status switch. The hose
should be connected to the high side of the switch. If the IDF is
configured to shut down the unit when this alarm occurs
(Configuration→UNIT→IDF.F = YES), then this alarm can
only be reset manually and the unit is shut down. If the IDF is
not configured to shut the unit down when this alarm occurs
(IDF.F = NO), then this alarm resets automatically and no
specific control action is taken.

Fan Status Switch Off, Fan Contactor On
This alert occurs when the fan status switch has sensed that the
indoor fan has been off for 10 seconds and the indoor fan
feedback has determined that the indoor fan should be on.
Because the Fan Status switch can be configured normally
opened or closed, the switch might be open or closed. The
configuration for this switch input can be found at
Configuration→UNIT→FN.SW. Verify that the configuration
is set correctly. Verify the wiring and fan status switch. The hose
should be connected to the high side of the switch. If the IDF is
configured to shut down the unit down when this alert occurs
(Configuration→UNIT→IDF.F = YES), then this alarm can
only be reset manually and the unit is shut down. If the IDF is
not configured to shut the unit down when this alert occurs
(IDF.F = NO), then this alert resets automatically and no specific
control action is taken.

Alert Code T414
There are 6 different alerts under this one alert code. Pressing enter

and esc on the marquee or navigator to expand the T414 alert will
show you one of the below alerts. All these alerts are generated by

the Belimo actuator and reported to the ECB. These alerts can only

occur if the ECB is controlling the actuator digitally through MFT.

Economizer Damper Actuator Out of Calibration
This alert occurs when the economizer actuator reports a control
angle (Operating Modes→ECON→C.ANG) less than the
minimum control angle (Configuration→ECON→M.ANG).

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