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Table 26 — Alarm and Alert Codes (cont)
LEGEND
Table 27 — Example of Reading and Clearing Alarms
ALARM/
ALERT CODE
ALARM OR
ALERT
DESCRIPTION WHY WAS THIS ALARM GENERATED?
ACTION TAKEN
BY CONTROL
RESET
METHOD
T153 Alert
Real Time Clock
Hardware Failure
Internal clock on MBB fails
Occupancy schedule will not
be used. Unit defaults to
Local On mode.
Automatic when
correct clock
control restarts.
A154 Alarm
Serial EEPROM
Hardware Failure
Hardware failure with MBB Unit is unable to run. Manual
T155 Alert
Serial EEPROM
Storage Failure
Configuration/storage failure with MBB No action Manual
A156 Alarm
Critical Serial EEPROM
Storage Failure
Configuration/storage failure with MBB Unit is not allowed to run. Manual
A157 Alarm A/D Hardware Failure Hardware failure with peripheral device Unit is not allowed to run. Manual
A170 Alarm
Loss of Communication
with CXB
MBB loses communication with CXB CXB functions disabled Automatic
A173 Alarm
Loss of Communication
with EMM
MBB loses communication with EMM
4 to 20 mA temperature
reset disabled. Demand Limit
set to 100%. 4 to 20 mA
set point disabled.
Automatic
T174 Alert
4 to 20 mA Cooling Set
Point/Desired % Capacity
Input Failure
If configured with EMM and input less than
2 mA or greater than 22 mA
Set point function/%
capacity function disabled.
Automatic
T176 Alert
4 to 20 mA Temperature
Reset Input Failure
If configured with EMM and input less than
2 mA or greater than 22 mA
Reset function disabled.
Unit returns to normal
set point control.
Automatic
T177 Alert
4 to 20 mA Demand Limit
Input Failure
If configured with EMM and input less than
2 mA or greater than 22 mA
Demand limit function
disabled. Unit returns to
100% demand limit control.
Automatic
A200 Alarm
Fan Status
Switch 1 Open
Alarm is generated when fan status switch 1
is open when the unit is in an ON state
Unit not allowed to start Automatic
T201 Alert
Fan Status Switch 1
is open with Dual TSTAT
configuration
Alert is generated when fan status switch 1
is open when Y1 or Y2 are closed
Circuit A is not allowed to run Automatic
T202 Alert
Fan Status Switch 2
is open with Dual TSTAT
configuration
Alert is generated when fan status switch 1
is open when Y3 or Y4 are closed
Circuit B is not allowed to run Automatic
T303 Alert
Condenser Coil
Maintenance Due
Coil Service Countdown (C.L.DN) expired.
Complete condenser coil cleaning and enter ‘YES’
for Coil Maintenance Done (C.L.MN) item.
None Automatic
T500 Alert
Current Sensor Board
A1 Failure
Alert occurs when CSB output
is a constant high value
Compressor A1 shut down Automatic
T501 Alert
Current Sensor Board
A2 Failure
Alert occurs when CSB output
is a constant high value
Compressor A2 shut down Automatic
T502 Alert
Current Sensor Board
A3 Failure
Alert occurs when CSB output
is a constant high value
Compressor A3 shut down Automatic
T503 Alert
Current Sensor Board
B1 Failure
Alert occurs when CSB output
is a constant high value
Compressor B1 shut down Automatic
T504 Alert
Current Sensor Board
B2 Failure
Alert occurs when CSB output
is a constant high value
Compressor B2 shut down Automatic
T505 Alert
Current Sensor Board
B3 Failure
Alert occurs when CSB output
is a constant high value
Compressor B3 shut down Automatic
CCN — Carrier Comfort Network
®
LWT — Leaving Fluid Temperature
CSB — Current Sensor Board MBB — Main Base Board
CXB — Compressor Expansion Module SCT — Saturated Condensing Temperature
DTT — Discharge Temperature Thermistor SST — Saturated Suction Temperature
EEPROM — Electrically Erasable Programmable
Read-Only Memory
TSTAT — Thermostat
EMM — Energy Management Module
SUB-MODE
KEYPAD
ENTRY
ITEM ITEM EXPANSION COMMENT
CRNT AXXX or TXXX CURRENTLY ACTIVE ALARMS
ACTIVE ALARMS (AXXX) OR
ALERTS (TXXX) DISPLAYED.
CRNT
RCRN
NO Use to clear active alarms/alerts
NO NO Flashes
YES Select YES
NO Alarms/alerts clear, YES changes to NO
ENTER
ESCAPE
ENTER
ENTER