127
Recovery from this alert is automatic. Reason for error is either a
faulty thermistor in the T55, T56, or T58 device, wiring error, or
damaged input on the MBB control board.
T075 (Return Air Thermistor Failure)
Failure of this thermistor (
Temperatures
AIR.T
RAT
) will
disable any elements of the control which require its use. Ele
-
ments of failure include:
• the calculation of mixed air temperature for SumZ control
• the selection of a mode for VAV units
• economizer differential enthalpy or dry bulb control
• RAT offset control for dehumidification
• return air temperature supply air reset
• fan tracking for building pressure control.
Recovery from this alert is automatic. Reason for error is either
a faulty thermistor, wiring error, or damaged input on the MBB
control board.
T076 (Outside Air Relative Humidity Sensor Fail)
Failure of this sensor (
Inputs
REL.H
OA.RH
) will disable
any elements of the control which require its use. Elements of
failure include economizer outdoor and differential enthalpy
control. Recovery from this alert shall be automatic. Reason
for error is either a faulty sensor, wiring error, or damaged in
-
put on the CEM control board.
T077 (Space Relative Humidity Sensor Failure)
Failure of this sensor (
Inputs
REL.H
SP.RH
) will disable
any elements of the control which require its use. Elements of
failure include humidification and dehumidification. Recovery
from this alert is automatic. Reason for error is either a faulty
sensor, wiring error, or damaged input on the CEM control
board.
T078 (Return Air Relative Humidity Sensor Fail)
Failure of this sensor (
Inputs
REL.H
RA.RH
) will disable
any elements of the control which require its use. Elements of
failure include economizer differential enthalpy control, hu
-
midification, and dehumidification. Recovery from this alert is
automatic. Reason for error is either a faulty sensor, wiring er
-
ror, or damaged input on the CEM control board.
T079 (Mixed Air Relative Humidity Sensor Fail)
Failure of this sensor (
Inputs
REL.H
MA.RH
) will disable
any elements of the control which require its use. Elements of
failure include humidification and dehumidification prognos
-
tics. Recovery from this alert is automatic. Reason for error is
either a faulty sensor, wiring error, or damaged input on the
CEM control board.
T082 (Space Temperature Offset Sensor Failure)
When this failure occurs, there is no offset available that may
be applied to space temperature. Recovery from this alert is au
-
tomatic. Reason for error is either a faulty slider potentiometer,
wiring error, or damaged input on the MBB control board.
T090 (Circ A Discharge Press Transducer Failure)
T091 (Circ B Discharge Press Transducer Failure)
The associated circuit becomes disabled whenever this trans
-
ducer (
Pressures
REF.P
DP.A, DP.B
) fails. Recovery from
this alert is automatic. Reason for error is either a faulty sensor,
wiring error, or damaged input on the MBB control board.
T092 (Circ A Suction Press Transducer Failure)
T093 (Circ B Suction Press Transducer Failure)
The associated circuit becomes disabled whenever this trans
-
ducer (
Pressures
REF.P
SP.A, SP.B
) fails. Recovery from
this alert is automatic. Reason for error is either a faulty sensor,
wiring error, or damaged input on the MBB control board.
T094 (Circ A EXV 1 Thermistor Failure)
T095 (Circ A EXV 2 Thermistor Failure)
The associated circuit becomes disabled whenever this therm
-
istor (
Temperatures
REF.T
ASX1, ASX2
) fails. Recovery
from this alert is automatic. Reason for error is either a faulty
sensor, wiring error, or damaged input on one of the EXV con
-
trol boards.
T096 (Circ B EXV1 Thermistor Failure)
T097 (Circ B EXV2 Thermistor Failure)
The associated circuit becomes disabled whenever this therm
-
istor (
Temperatures
REF.T
BSX1
,
BSX2
) fails. Recovery
from this alert is automatic. Reason for error is either a faulty
sensor, wiring error, or damaged input on one of the EXV con
-
trol boards.
T098 (Circuit A Liquid Temperature Thermistor Failure)
T099 (Circuit B Liquid Temperature Thermistor Failure)
Failure of this sensor (
Temperatures
REF.T
LT.A, LT.B
)
will disable any elements of the control which require its use.
Elements of failure include charge determination and prognos
-
tics. Recovery from this alert is automatic. Reason for error is
either a faulty sensor, wiring error, or damaged input on one of
the EXV control boards.
T100 (Circ A Liquid Press Transducer Failure)
T101 (Circ B Liquid Press Transducer Failure)
Failure of this sensor (
Pressures
REF.P
LP.A, LP.B
) will
disable any elements of the control which require its use. Ele
-
ments of failure include charge determination and prognostics.
Recovery from this alert is automatic. Reason for error is either
a faulty sensor, wiring error, or damaged input on the SCB con
-
trol board.
T110 (Circuit A Loss of Charge)
T111 (Circuit B Loss of Charge)
Alert codes 110 and 111 are for Circuits A and B respectively.
These alerts occur when all the compressors on a circuit are
OFF and the suction pressure is less than 18 psig, if the OAT is
above –5°F for 1 continuous minute. The alert will automati
-
cally clear when the suction pressure transducer reading is val
-
id and greater than 54 psig. The cause of the alert is usually
low refrigerant pressure or a faulty suction pressure transducer.
T112 (Low Circuit A Charge Detected)
T113 (Low Circuit B Charge Detected)
Alert codes 112 and 113 are for Circuits A and B respectively.
These alerts occur when a charge determination using liquid
sensors test has been run and the charge has been calculated to
be less than
Configuration
IAQ
PROG
AC.CL
. This re
-
sult typically indicates charge should be added to the system.
The alert will automatically clear when the test is re-run and
the charge is calculated to be greater than
AC.CL
. The cause of
the alert is usually low refrigerant charge.
T114 (High Circuit A Charge Detected)
T115 (High Circuit B Charge Detected)
Alert codes 114 and 115 are for Circuits A and B respectively.
These alerts occur when a charge determination using liquid
sensors test has been run and the charge has been calculated to
be greater than
Configuration
IAQ
PROG
AC.CH
. This
result typically indicates charge should be removed to the sys
-
tem. The alert will automatically clear when the test is re-run
and the charge is calculated to be less than
AC.CH
. The cause
of the alert is usually high refrigerant charge.
Summary of Contents for WeatherExpert 48N2
Page 135: ...135 Fig 18 48 50N Typical Power Schematic Nominal 075 Ton Unit Shown ...
Page 136: ...136 Fig 19 48 50N Typical Power Schematic Nominal Ton 90 150 Units Shown ...
Page 137: ...137 Fig 20 48 50N Main Base Board Input Output Connections ...
Page 138: ...138 Fig 21 48 50N RXB EXB CEM Input Output Connections a48 9307 ...
Page 139: ...139 Fig 22 48 50N EXV SCB Input Output Connections a48 9308 ...
Page 140: ...140 Fig 23 48N Typical Modulating Gas Heat Unit Control Wiring ...
Page 141: ...141 Fig 24 50N Typical Electric Heat Unit Control Wiring ...
Page 144: ...144 Fig 27 48N Typical Gas Heat Section Wiring Nominal Ton 120 to 150 Units ...
Page 145: ...145 Fig 28 48 50N Typical Power Component Control Wiring 460 v ...
Page 146: ...146 Fig 29 48 50N Component Control Wiring 575 v Nominal Ton 075 to 150 Units ...
Page 147: ...147 Fig 30 48 50N Component Arrangement Power Box ...
Page 148: ...148 Fig 31 48 50N Component Arrangement Control Box ...
Page 240: ...240 APPENDIX D VFD INFORMATION CONT Fig G VFD Bypass Wiring Diagram WHEN USED ...