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A171 (Staged Gas Control Board Comm Failure)
Staged Heating is disabled until communication with the staged
gas control board is re-established. Recovery is automatic. Rea-
son for failure may be incorrect wiring, power loss to the staged
gas control board, or damage to the RS-485 drivers on the LEN
bus.
T172 (Control Expansion Module Comm Failure)
Any function associated with a sensor configured for use that re-
sides on the controls expansion module will be disabled until com-
munication is re-established. Recovery is automatic. Reason for
failure may be incorrect wiring, power loss to the control expan-
sion module, or damage to the RS-485 drivers on the LEN bus.
A173 (RXB Board Communication Failure)
As the RXB board is integral to all P Series units, the error will
cause a system shutdown until communication is re-established.
Recovery is automatic. Reason for failure may be incorrect wir-
ing, power loss to the RXB board, or damage to the RS-485 driv-
ers on the LEN bus.
A174 (EXB Board Communication Failure)
The EXB board is responsible for building pressure control.
Building Pressure control configurations that require this board
will cause a complete system shut down when communication
failure occurs. Recovery is automatic. Reason for failure may be
incorrect wiring, power loss to the EXB board, or damage to the
RS-485 drivers on the LEN bus.
A175 (Supply Fan VFD Communication Failure)
The supply fan is disabled until communication with the supply
fan VFD is re-established. Recovery is automatic. Reason for fail-
ure may be incorrect wiring, power loss to the VFD, or damage to
the RS-485 drivers on the LEN bus.
T176 (Exhaust Fan VFD Communication Failure)
The exhaust fan is disabled until communication with the exhaust
fan VFD is re-established. Recovery is automatic. Reason for fail-
ure may be incorrect wiring, power loss to the VFD, or damage to
the RS-485 drivers on the LEN bus.
T177 (4-20 mA Demand Limit Failure)
If this transducer fails, and the unit is configured to perform de-
mand limiting with this transducer, no capacity limiting will be
performed and an alert will be generated. Recovery is automatic.
Reason for error is either a faulty sensor, wiring error, or dam-
aged input on the CEM control board.
T178 (4-20 mA Static Pressure Reset Fail)
If this transducer fails, and the unit is configured to perform static
pressure reset with this transducer, no static pressure reset will be
performed and an alert will be generated. Recovery is automatic.
Reason for error is either a faulty sensor, wiring error, or damaged
input on the CEM control board.
A179 Circuit A ODF VFD Failure
The MBB has received a fault status from the outdoor fan VFD(s).
The A circuit of the 70/75 ton unit or the whole unit will not be al-
lowed to operate, and a reset is required. The VFD keypad will in-
dicate which fault has occurred.
A180 Circuit B ODF VFD Failure
The MBB has received a fault status from the outdoor fan VFD(s).
The B circuit of the 70/75 ton unit or the whole unit will not be al-
lowed to operate, and a reset is required. The VFD keypad will in-
dicate which fault has occurred.
A181 Circuit A ODF VFD Communication Failure
This alarm indicates that there are communication problems with
the Circuit A OD fan VFD. The cooling function on the A circuit
or the unit is disabled until communication with the OD fan
VFD(s) is re-established.
A182 Circuit B ODF VFD Communication Failure
This alarm indicates that there are communication problems with
the Circuit B OD fan VFD. The cooling function on the B circuit
or the unit is disabled until communication with the OD fan
VFD(s) is re-established.
T183 (Compressor Lockout Low Ambient)
When the outdoor ambient temperature (OAT) is below the com-
pressor lockout temperature setting (OATLCOMP), an alert will
occur to indicate the setting situation. If the unit is equipped with
Low Ambient or GreenSpeed option, the OATLCOMP setting can
be lower than the default 53°F to the minimum of –20°F.
A200 (Linkage Timeout Error — Comm Failure)
If linkage is established via the CCN with ComfortID™ termi-
nals, a 5-minute timeout on loss of communication will be moni-
tored. If 5 minutes expires since the last communication from a
VAV Linkage Master, the unit will remove the link and flag the
alert. When the rooftop loses its link, the temperature and set
points are derived locally. Recovery is automatic on re-establish-
ment of communications. Reason for failure may be wiring er-
ror, too much bus activity, or damaged RS-485 drivers.
T210 (Building Pressure Transducer Failure)
If the building pressure transducer (Pressures
fails, building pressure control fails also. Recovery is automatic.
Reason for error is either a faulty sensor, wiring error, or damaged
input on the RXB control board.
T211 (Static Pressure Transducer Failure)
If the static pressure transducer (Pressures
static pressure control fails also. Recovery is automatic. Reason
for error is either a faulty sensor, wiring error, or damaged input on
the RXB control board.
T220 (Indoor Air Quality Sensor Failure)
If the indoor air quality sensor (Inputs
mand controlled ventilation is not possible. The control defaults to
the max vent position. Recovery is automatic. Reason for error is
either a faulty sensor, wiring error, or damaged input on the MBB
control board.
T221 (Outdoor Air Quality Sensor Failure)
If the outdoor air quality sensor (Inputs
OAQ defaults to 400 ppm and demand controlled ventilation will
continue. Recovery is automatic. Reason for error is either a faulty
sensor, wiring error, or damaged input on the CEM control board.
T229 (Economizer Min Pos Override Input Failure)
If the economizer minimum position override input fails, the
economizer will operate as if it were not configured for override.
Recovery is automatic. Reason for error is either a faulty sensor,
wiring error, or damaged input on the MBB control board. This
error only occurs when the unit is configured for minimum posi-
tion override and a 4 to 20 mA signal is not present.
T245 (Outside Air Cfm Sensor Failure)
If the outside air cfm sensor (Inputs
economizer will default to discrete positioning of the economiz-
er (Configuration
IAQ
ECON
EC.MN). Recovery is automatic. Reason for error is
either a faulty sensor, wiring error, or damaged input on the
CEM control board.
T246 (Supply Air Cfm Sensor Failure)
If the supply air cfm sensor (Inputs
tracking is not possible and the system will shut down. Recovery
is automatic. Reason for error is either a faulty sensor, wiring er-
ror, or damaged input on the EXB control board.
T247 (Return Air Cfm Sensor Failure)
If the return air cfm sensor (Inputs
tracking is not possible and the system will shut down. Recovery
is automatic. Reason for error is either a faulty sensor, wiring er-
ror, or damaged input on the EXB control board.
T300 (Space Temperature Below Limit)
If space temperature is below configurable SPT Low Alert Limits
(occupied [Configuration
129
AIR.P
AIR.P
AIR.Q
IAQ) fails, de-
AIR.Q
OAQ) fails,
CFM
O.CFM) fails, the
DCV.C
IAQ.M, Configuration
CFM
S.CFM) fails, fan
CFM
R.CFM) fails, fan
ALLM
SP.L.O] for 5 minutes or
BP)
SP) fails,
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Table of Contents
Troubleshooting
