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Table 38 — Alarm and Alert Codes (cont)
See legend on page 51.
ALARM/
ALERT
CODE
ALARM
OR
ALERT
DESCRIPTION
WHY WAS THIS
ALARM
GENERATED?
ACTION TAKEN
BY CONTROL
RESET
METHOD
PROBABLE
CAUSE
A116 Alarm
Circuit A Low Cooler
Suction Temperature
Mode 7 caused the com-
pressor to unload 6 consecu-
tive times with less than a
30-minute interval between
each circuit shutdown.
Circuit shut down Manual
Faulty expansion valve, low
refrigerant charge, plugged
filter drier, faulty suction
pressure transducer, low
cooler fluid flow
A122 Alarm
High Pressure Switch
Trip Circuit A
High Pressure A Switch
Input opento MBB
Circuit shut down Manual
Faulty transducer/high
pressure switch.
A126 Alarm
Circuit A High
Discharge Pressure
SCT >Maximum condensing
temperature from operating
envelope
Circuit shut down
Automatic, only
after first 3 daily
occurrences.
Manual reset
thereafter. Read-
ing from OAT sen-
sor must drop 5 F
(2.8 C) before
restart
Faulty transducer/high
pressure switch, low/
restricted condenser
airflow
T133 Alert
Circuit A Low Suction
Pressure
Suction pressure below
34 psig for 8 seconds or
below 23 psig
Circuit shut down
Automatic
restart after first
daily occurrence.
Manual restart
thereafter.
Faulty or plugged EXV, low
refrigerant charge, EXV out
of adjustment, liquid
line valve partially closed
A140 Alert
Reverse Rotation
Detected
Incoming chiller power leads
not phased correctly
Chiller not allowed to
start.
Manual
Reverse any two incoming
power leads to correct. Check
for correct fan rotation first.
A150 Alarm Emergency Stop
CCN emergency stop
command received
Chiller shutdown
without going through
pumpdown.
Automatic once
CCN command for
EMSTOP returns to
normal
CCN Network
command.
A151 Alarm Illegal Configuration
One or more illegal
configurations exists.
Chiller is not allowed to
start.
Manual once
configuration errors
are corrected
Configuration error.
Check unit settings.
A152 Alarm
Unit Down Due to
Failure
Both circuits are down due
to alarms/alerts.
Chiller is unable
to run.
Automatic once
alarms/alerts are
cleared that pre-
vent the chiller from
starting.
Alarm notifies user
that chiller is 100%
down.
T153 Alert
Real Time Clock
Hardware Failure
Internal clock on MBB fails
Occupancy schedule
will not be used. Chiller
defaults to Local On
mode.
Automatic when
correct clock con-
trol restarts.
Time/Date/Month/
Day/Year not
properly set.
A154 Alarm
Serial EEPROM
Hardware Failure
Hardware failure with MBB
Chiller is unable
to run.
Manual
Main Base Board
failure.
T155 Alert
Serial EEPROM
Storage Failure
Configuration/storage
failure with MBB
No Action Manual
Potential failure of
MBB. Download
current operating
software. Replace
MBB if error occurs again.
A156 Alarm
Critical Serial EEPROM
Storage Failure
Configuration/storage
failure with MBB
Chiller is not allowed
to run.
Manual
Main Base Board
failure.
A157 Alarm A/D Hardware Failure
Hardware failure with
peripheral device
Chiller is not allowed
to run.
Manual
Main Base Board
failure.
T173 Alert
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
Wiring error, faulty
wiring or failed
Energy Management Module
(EMM).
T174 Alert
4 to 20 mA Cooling Set
Point Input Failure
If configured with EMM and
input less than 2 mA or
greater than 22 mA
Set point function
disabled. Chiller
controls to CSP1.
Automatic
Faulty signal
generator, wiring
error, or faulty EMM.
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. Chiller
returns to normal set
point control.
Automatic
Faulty signal
generator, wiring
error, or faulty EMM.
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. Chiller
returns to 100%
demand limit
control.
Automatic
Faulty signal
generator, wiring
error, or faulty EMM.