Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service, And Troubleshooting page 133

reasonable time to catch the failure. Compressors will be not be
inhibited by this failure. Recovery is automatic. Reason for fail-
ure may be a faulty current sensor board, incorrect wiring, or a
damaged input on the CXB control board.
T610 (Economizer 1 Actuator Out of Calibration)
T620 (Economizer 2 Actuator Out of Calibration)
T650 (Economizer 3 Actuator Out of Calibration)
T630 (Humd/HTC-2 Actuator Out of Calibration)
A640 (Heating Coil Actuator Out of Calibration)
A660 (Heating Actuator 3 Out of Calibration)
A670 (Heating Actuator 4 Out of Calibration)
Each of the actuators must have a minimum control range to
operate. If the actuator, after a calibration, has not learned a
control range appropriate for the application, this alarm/alert
will be sent. No action will be taken on this error. Recovery is
automatic. Reason for failure may be an obstruction or stuck
linkage that prevents full range calibration.
T611 (Economizer 1 Actuator Comm Failure)
T621 (Economizer 2 Actuator Comm Failure)
A641 (Heating Coil Actuator Comm Fail)
T651 (Economizer 3 Actuator Comm Failure)
T631 (Humd/HTC-2 Actuator Communication Failure)
A661 (Heating Actuator 3 Comm Failure)
A671 (Heating Actuator 4 Comm Failure)
Each of the actuators communicates over the local equipment
network (LEN). If this error occurs, then it is impossible to
control the actuator. Depending on the function of the actuator,
the control will shut down any process associated with this ac-
tuator. Recovery is automatic. Reason for failure may be incor-
rect wiring, incorrect serial number configuration, or damaged
RS-485 drivers on the LEN bus.
T612 (Economizer 1 Actuator Control Range Increased)
T622 (Economizer 2 Actuator Control Range Increased)
T632 (Humd/HTC-2 Actuator Control Range Increased)
T642 (Heating Coil Actuator Control Range Increased)
T652 (Economizer 3 Actuator Control Range Increased)
T662 (Heating Actuator 3 Control Range Increased)
T672 (Heating Actuator 4 Control Range Increased)
The actuators, once properly calibrated, learn their end stops for
movement. During normal operation, if the actuator perceives
that the actuator is able to go farther than its learned range of op-
eration, this error will be broadcast. Reason for failure may be a
slipping of the linkage and, therefore, this error may mean that
the actuator cannot perform its assigned function. Recovery re-
quires a fix of any slipped linkage and/or a re-calibration.
T613 (Economizer 1 Actuator Overload, Setpoint Not Reached)
T623 (Economizer 2 Actuator Overload, Setpoint Not Reached)
T633 (Humd/HTC-2 Actuator Overload, Setpoint Not Reached)
A643 (Heating Coil Actuator Overload, Setpoint Not Reached)
T653 (Economizer 3 Actuator Overload, Setpoint Not Reached)
A663 (Heating Actuator 3 Overload, Setpoint Not Reached)
A673 (Heating Actuator 4 Overload, Setpoint Not Reached)
If an actuator is unable to achieve a commanded position with-
in a reasonable period of time, this alarm or alert will be broad-
cast. This may be an indication of a stuck actuator. No action is
taken. Recovery is automatic.
T614 (Economizer 1 Excessive Utilization)
T624 (Economizer 2 Actuator Excessive Utilization)
T634 (Humd/HTC-2 Actuator Excessive Utilization)
A644 (Heating Coil Actuator Excessive Utilization)
T654 (Economizer 3 Actuator Excessive Utilization)
A664 (Heating Actuator 3 Excessive Utilization)
A674 (Heating Actuator 4 Excessive Utilization)
This alert occurs when the commanded actuator position is
changing too rapidly. Recovery is automatic.
T615 (Econ 1 (Outside 1) Not Economizing When it Should)
T625 Econ 2 (Return) Not Economizing When It Should
T655 Econ 3 (Outside 2) Not Economizing When it Should
When the control detects a stuck or jammed actuator, it shall com-
pare the stuck position to the command position to log additional
alerts. If the stuck position < commanded position, the alert is set.
T616 (Econ 1 (Outside 1) Economizing When It Should Not)
T626 Econ 2 (Return) Economizing When It Should Not)
T656 Econ 3 (Outside 2) Economizing When It Should Not
When the control detects a stuck or jammed actuator, it shall com-
pare the stuck position to the command position to log additional
alerts. If the stuck position > commanded position, the alert is set.
T617 (Econ 1 (Outside 1) Damper Stuck Or Jammed)
T627 Econ 2 (Return) Damper Stuck Or Jammed
T657 Econ 3 (Outside 2) Damper Stuck Or Jammed
The actuator is no longer moving and the actual position is
greater than or less than E.GAP% of the commanded position
for E.TMR seconds. Reset is automatic.
A700 (Air Temp Lvg Supply Fan Thermistor Failure)
The failure of this sensor will shut the system down and generate
an alarm, as this thermistor is a critical component to fundamental
operation and diagnosis of the rooftop unit. Recovery is automatic.
Reason for failure may be incorrect wiring, a faulty thermistor, or
a damaged input on the MBB control board.
T701 (Staged Gas 1 Thermistor Failure)
T702 (Staged Gas 2 Thermistor Failure)
T703 (Staged Gas 3 Thermistor Failure)
If any of the staged gas thermistors (Temperatures  AIR.T 
S.G.L1-3) fails, an alert will be generated and the remaining
thermistors will be averaged together (Temperatures  AIR.T
 S.G.LS) without the failed thermistor. Recovery is automatic.
Reason for failure may be incorrect wiring, faulty thermistor, or
damaged input on staged gas control board (SCB).
A704 (Staged Gas Lvg Air Temp Sum Total Failure)
If all 3 staged heat thermistors (Temperatures  AIR.T 
S.G.L1,2,3) fail, staged heat will be shut down and this alarm
will be generated. Recovery is automatic. Reason for failure
may be faulty wiring, faulty thermistors, or damaged inputs on
the staged gas control board (SCB).
T705 (Limit Switch Thermistor Failure)
A failure of this thermistor (Temperatures  AIR.T  S.G.LM)
will cause an alert to occur and a disabling of the limit switch
monitoring function for the staged gas control board (SCB).
Recovery is automatic. Reason for failure may be due to faulty
wiring, a faulty thermistor, or a damaged input on the staged
gas control board (SCB).
A706 (Hydronic Evap Discharge Thermistor Failure)
If the unit is configured for hot water heating (hydronic), then
the unit has a thermistor (Temperatures  AIR.T  CCT) in-
stalled between the evaporator coil and the hot water coils that
functions as the evaporator discharge temperature thermistor
for cooling. If this thermistor fails, an alarm will be generated
and the system will be shut down. Recovery is automatic. Rea-
son for failure may be due to faulty wiring, a faulty thermistor,
or a damaged input on the EXB control board.
A707 (Digital Scroll A1 Discharge Thermistor Failure)
If the RXB control board is not receiving a signal from the dis-
charge temperature thermistor, the alarm is generated. The therm-
istor may be missing or disconnected, or a wire may be broken.
The alert will be generated and the digital scroll capacity will
be locked at 50%. Reset is automatic.
T800 (Cannot Enable MLV and Digital Scroll Simultaneously)
This alert occurs when both MLV and digital scroll are enabled
in the field. These controls should not be enabled at the same
time as cooling capacity control and compressor reliability can
be compromised. Disable either MLV or digital scroll.
133