Specifications

82
sensor is located in the economizer hood and is used for control
of the economizer. The sensor is a loop powered 4 to 20 mA
sensor. This alert resets automatically. The cause of the alert
is usually a faulty sensor, a shorted or open sensor caused
by a wiring error, or a loose connection. The unit must be
configured to use the sensor through the Outside Air RH Sensor
(Configuration
→ ECON → ORH.S) setting.
Alert Code 78 (Return Air Relative Humidity Sensor Fail-
ure) — This alert occurs when the return air humidity sensor
(Inputs → REL.H → RA.RH) has a reading less than 2 mA or
greater than 22 mA. Failure of this sensor (Inputs
→
REL.H → RA.RH) will disable any elements of the control
which requires its use including economizer differential
enthalpy control.
The RA.RH sensor is located in the return air section near
the auxiliary control box. The sensor is a loop powered 4 to
20 mA sensor. This alert resets automatically. The cause of the
alert is usually a faulty sensor, a shorted or open sensor caused
by a wiring error, or a loose connection. The unit must be con-
figured to use the sensor through the Outside Air RH Sensor
(Configuration
→ SENS → RRH.S) setting.
Alert Code 82 (Space Temperature Offset Failure)
— If the
unit is configured to use a space temperature sensor and is
using a T56 sensor with an offset potentiometer, then the alert
will occur if the potentiometer is outside the allowable range.
The control will default to the software applicable set point
because there is no offset available that may be applied to
space temperature. The alert will automatically clear. The unit
must be configured for one of the SPT control options
through the Unit Control Type (Configuration
→ UNIT →
C.TYP) configuration.
Alert Codes 92, 93, (Suction Pres. Trans. Failure)
—Alert
codes 92, and 93 are for circuits A and B respectively. These
alerts occur when the pressure is outside the range 0.5 to
134.5 psig. A circuit cannot run when this alert is active. Use
the Scrolling Marquee to reset the alert. The cause of the alert
is usually a faulty transducer, faulty 5v power supply, or a loose
connection.
Alert Codes 110, 111 (Loss of Charge)
—Alertcodes110,
and 111 are for circuits A, and B respectively. These alerts occur
when the compressor is OFF and the suction pressure is less
than 5 psig and the OAT is above –5 F for 1 continuous minute.
The alert will automatically clear when the suction pressure
transducer reading is valid and greater than 15 psig. The cause
of the alert is usually low refrigerant pressure or a faulty suction
pressure transducer.
Alert and Alarm Code 120, 121 (Low Saturated Suction Tem-
perature) — Alert codes 120 and 121 are used to protect the
coil from freeze-up during operation. Alert 120 is for circuit A
and 121 for circuit B. If the saturated suction temperature is
less than 28 F for 15 minutes, less than 20 F for 5 minutes, or
less than 5 F for 20 continuous seconds then the alert will occur
for the appropriate circuit. The circuit will be allowed to restart
in 15 minutes. If more than three alerts occur then the circuit
will be locked out and an alarm is generated. If the saturated
suction is greater than 34 F for more than one hour then the
counter will be reset.
Alert Code 122 and 123 (High Saturated Suction Tempera-
ture) — Alert codes 122 and 123 occur when compressors in a
circuit have been running for at least 5 minutes and the circuit
saturated suction is greater than 60 F. The high saturated suc-
tion alert is generated and the circuit is shut down. This condi-
tion resets after OAT drops by 5° F. Alert code 122 is for circuit
A and 123 for circuit B.
Alert Codes 126, 127 (Circuit High Head Pressure)
—Alert
codes 126, and 127 are for circuits A and B respectively. These
alerts occur when the appropriate saturated condensing temper-
ature is greater than 150 F. The cause of the alarm is usually
an overcharged system, high outdoor ambient temperature
coupled with dirty outdoor coil, plugged filter drier, or a faulty
high-pressure switch.
The alert will clear automatically or when the OAT drops
5° F from the time of the alert.
Alarm Code 150 (Unit in Emergency Stop)
— If the fire
safety input condition occurs to indicate a fire or smoke condi-
tion, then Alarm code 150 will occur and the unit will be
immediately stopped. Through separate inputs the unit can be
put into purge, evacuation, and pressurization. This requires a
manual reset.
If the CCN point name “EMSTOP” in the System table is
set to emergency stop, the unit will shut down immediately and
broadcast an alarm back to the CCN indicating that the unit is
down. This alarm will clear when the variable is set back to
“enable”.
Alert Code 153 — Real Time Clock Hardware Failure
—
A problem has been detected with the real timeclock on the
MBB. Try resetting the power and check the indicator lights. If
the alert continues, the board should be replaced.
Alarm Code 154 — Serial EEPROM Hardware Failure
—
A problem has been detected with the EEPROM on the MBB.
Try resetting the power and check the indicator lights. If the
alarm continues, the board should be replaced.
Alert Code 155 — Serial EEPROM Storage Error
—A
problem has been detected with the EEPROM storage on the
MBB. Try resetting the power and check the indicator lights. If
the alert continues, the board should be replaced.
Alarm Code 156 — Critical Serial EEPROM Storage Error
— A problem has been detected with the EEPROM storage on
the MBB. Try resetting the power and check the indicator
lights. If the alarm continues, the board should be replaced.
Alarm Code 157 — A/D Serial EEPROM Storage Failure
Error — A problem has been detected with A/D conversion on
the boards. Try resetting the power and check the indicator
lights. If the alarm continues, the board should be replaced.
Alarm Code 171 — Loss of Communications with the
Staged Gas Control Board — This alarm indicates that there
are communications problems with the staged gas heat control
board, which is located in the gas section on units equipped
with staged gas heat. If this alarm occurs, the staged gas heat
will be disabled. The alarm will automatically reset.
Alarm Code 172 — Loss of Communications with the Con-
trols Expansion Board — This alarm indicates that there are
communications problems with the Controls Expansion Board.
All functions performed by the CEM will stop, which can in-
clude demand limit, reset, fire control modes, and the fan status
switch. The alarm will automatically reset.
Alarm Code 173 — Loss of Communications with the
ECB1 — This alarm indicates that there are communications
problems with the Economizer Control Board. This will result
in the economizer and the power exhaust not working and the
dampers to be fully closed. The exhaust fans will stop. The
alarm will automatically reset.
Alarm Code 174 — Loss of Communications with the
ECB2 — This alarm indicates that there are communications
problems with the ECB2 which controls the VAV unit indoor
fan inverter speed and hot gas bypass on CV and VAV units.
Because the control of the fan is critical to unit operation, the
unit will be stopped. The alarm will automatically reset.
Alert Code 177 (4-20 mA Demand Limit Failure)
— This
alert indicates a problem with the optional remote 4 to 20 mA
demand limit signal (Inputs
→ 4-20 → DLM.M) that is connect-
ed to the CEM module (if the signal reads less than 2 mA or is
above 22 mA). If this occurs, then demand limiting will be dis-
abled. The unit must be configured for 4 to 20 mA Demand
Limiting using the Demand Limit Select (Configuration
→
DMD.L → DM.L.S).