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.
SFan 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.
SFan 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.
SEconomizer 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).