Carrier 48LC Series Controls, Start-Up, Operation And Troubleshooting page 34

Alert A105 – OAT OPEN SENSOR
See Alert A104.
Alert A106 – OAT SHORTED SENSOR
See Alert A104.
Alert A107 - RAT SENSOR RANGE
This alert occurs when the return air temperature is outside the
range –40°F to 245°F (–40°C to 116°C). Differential dry bulb
crossover control can not occur. Free cooling can only be con-
trolled by the OAT and enthalpy switch. The economizer me-
chanically disconnected alert will not be diagnosed. This alert
resets automatically. The cause of the alert is usually a faulty
thermistor, a shorted or open thermistor caused by a wiring er-
ror, or a loose connection.
Alert A108 – RAT OPEN SENSOR
See Alert A107.
Alert A109 – RAT SHORTED SENSOR
See Alert A107.
Alert A110 – SPT SENSOR RANGE
This alert occurs when the temperature is outside the range
–40°F to 245°F (–40°C to 116°C). Cooling and heating will not
operate. For economizer equipped units, the economizer will
still operate for ventilation. This alert resets automatically. The
cause of the alert is usually a faulty thermistor in the T-55,
T-56, or T-58 device, a shorted or open thermistor caused by a
wiring error, or a loose connection.
Alert A111 – SPT OPEN SENSOR
See Alert A110.
Alert A112 – SPT SHORTED SENSOR
See Alert A110.
Alert A130 – CIR.A SSP SENSOR RANGE
This alert occurs when the pressure is outside the range –6.7 psig
to 420 psig. A circuit cannot run when this alert is active. The
cause of the alert is usually a faulty transducer, faulty 5-v power
supply, or a loose connection. Use Table 25 on page 51 to deter-
mine where the error is introduced.
Alert A131 – CIR.A SSP OPEN SENSOR
See Alert A130.
Alert A132 – CIR.A SSP SHORT SENSOR
See Alert A130.
Alert A133 – CIR.A SDP SENSOR RANGE
This alert occurs when the pressure is outside the range 14.5 psig
to 667 psig. A circuit cannot run when this alert is active. The
cause of the alert is usually a faulty transducer, faulty 5-v power
supply, or a loose connection. Use Table 25 on page 51 to deter-
mine where the error is introduced.
Alert A134 – CIR.A SDP OPEN SENSOR
See Alert A130.
Alert A135 – CIR.A SDP SHORT SENSOR
See Alert A130.
Alert 150 - OACFM OPEN SENSOR
This alert occurs when the Outdoor Air CFM sensor input is
0 mA and the sensor is configured and installed. Check sensor
and wiring. This alert clears automatically.
Alert 151 - OACFM SHORTED SENSOR
This alert occurs when the Outdoor Air CFM sensor input
shorted and the sensor is configured as installed. Check sensor
and wiring. This alert clears automatically.
Alert A160 – OARH OPEN SENSOR
This alert occurs when the Outdoor Air Relative Humidity sen-
sor input is 0 mA and the sensor is configured as installed. Out-
side Air Enthalpy cannot be calculated, therefore no enthalpy
crossover can be used and only dry bulb will be used in
determining free cooling. Check sensor and wiring. This alert
clears automatically.
Alert A161 – OARH SHORTED SENSOR
This alert occurs when the Outdoor Air Relative Humidity sen-
sor input shorted and the sensor is configured as installed. Out-
side Air Enthalpy cannot be calculated; therefore, no enthalpy
crossover can be used and only dry bulb will be used in deter-
mining free cooling. Check sensor and wiring. This alert clears
automatically.
Alert A162 – RARH OPEN SENSOR
This alert occurs when the Return Air Relative Humidity sen-
sor input is 0 mA and the sensor is configured as installed. Re-
turn Air Enthalpy cannot be calculated; therefore, no differen-
tial enthalpy crossover can be used. Dry bulb and single enthal-
py will be used in determining free cooling. Check sensor and
wiring. This alert clears automatically.
Alert A163 – RARH SHORTED SENSOR
This alert occurs when the Return Air Relative Humidity sen-
sor input shorted and the sensor is configured as installed. Re-
turn Air Enthalpy cannot be calculated; therefore, no differen-
tial enthalpy crossover can be used. Dry bulb and single enthal-
py will be used in determining free cooling. Check sensor and
wiring. This alert clears automatically.
Alert A164 - IAQ OPEN SENSOR
This alert occurs when the IAQ input is 0 mA and the sensor is
configured as installed. IAQ operation will be disabled. Check
sensor and wiring. This alert clears automatically.
Alert A165 - IAQ SHORTED SENSOR
This alert occurs when the IAQ input is shorted and the sensor
is configured as installed. IAQ operation will be disabled.
Check sensor and wiring. This alert clears automatically.
Alert A166 - OAQ OPEN SENSOR
This alert occurs when the OAQ input is 0 mA and the sensor
is configured as installed. OAQ operation will be disabled.
Check sensor and wiring. This alert clears automatically.
Alert A167 - OAQ SHORTED SENSOR
This alert occurs when the OAQ input is shorted and the sensor
is configured as installed. OAQ operation will be disabled.
Check sensor and wiring. This alert clears automatically.
Alert A168 - SPACE RELATIVE HUMIDITY OPEN SENSOR
This alert occurs when the SPRH input is 0 mA and the sensor
is configured as installed. Check sensor and wiring. This alert
clears automatically.
Alert A169 - SPACE HUMIDITY SHORTED SENSOR
This alert occurs when the SPRH input is shorted and the sen-
sor is configured as installed. Check sensor and wiring. This
alert clears automatically.
Alert A170 - ECON FEEDBACK RANGE
This alert occurs when the Economizer analog feedback signal
is outside the range of 1.3vdc to 10.3vdc and the feedback is
configured to use. A short is 10.5vdc and an open circuit is less
than 0.1vdc. Economizer diagnostics operation will be dis-
abled. This is usually caused by a wiring problem, actuator
failure, or the wrong actuator. Investigate using the Low Volt-
age schematics in Fig. 24-28 ; make sure the feedback signal
from the actuator is correct. This alert clears automatically.
Alert A171 – ECON FEEDBACK OPEN
See Alert A170.
Alert A172 – ECON FEEDBACK SHORTED
See Alert A170.
Alert A190 – TSTAT HEAT/COOL CALLS
This alert occurs in Thermostat mode when Y1, Y2, or Y3 is
energized simultaneously with W1 or W2. Verify thermostat
and thermostat wiring. The software will enter either the
34