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will shut down any process associated with this actuator. Recovery
is automatic. Reason for failure may be incorrect wiring, incorrect
serial number configuration, or damaged RS-485 drivers on the
LEN bus.
T612 (Economizer Actuator Control Range Increased)
T622 (Economizer 2 Actuator Control Range Increased)
T632 (Humidifier Actuator Control Range Increased)
T642 (Heat Coil Actuator Control Range Increased)
T652 (Bldg.Press. Act. 1 Control Range Increased)
T662 (Bldg.Press. Act. 2 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 requires
a fix of any slipped linkage and/or a re-calibration.
T613 (Econ Actuator Overload, Setpt Not Reached)
A623 (Econ2 Actuator Overload, Setpt Not Reached)
T633 (Humidifier Act Overload, Setpt Not Reached)
A643 (Ht Coil Act Ovrload, Setpt Pos Not Reached)
A653 (BP Act. 1 Overload, Setpnt Pos Not Reached)
A663 (BP Act. 2 Overload, Setpnt Pos Not Reached)
If an actuator is unable to achieve a commanded position within a
reasonable period of time, this alarm or alert will be broadcast.
This may be an indication of a stuck actuator. No action is taken.
Recovery is automatic.
T614 (Economizer Actuator Hunting Excessively)
A624 (Economizer 2 Actuator Hunting Excessively)
T634 (Humidifier Actuator Hunting Excessively)
A644 (Heat Coil Actuator Hunting Excessively)
A654 (Bldg.Press. Actuator 1 Hunting Excessively)
A664 (Bldg.Press. Actuator 2 Hunting Excessively)
This alert occurs when the commanded actuator position is chang-
ing too rapidly. Recovery is automatic.
T615 Econ 1 (Outside) Not Economizing When It Should
When the control detects a stuck actuator, it will compare 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) Economizing When It Should Not
When the control detects a stuck or jammed actuator, it will 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) 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.
T625 Econ 2 (Return) Not Economizing When It Should
When the control detects a stuck actuator, it will compare the
stuck position to the command position to log additional alerts. If
the stuck position < commanded position the alert is set.
T626 Econ 2 (Return) Economizing When It Should Not
When the control detects a stuck or jammed actuator, it will com-
pare the stuck position to the command position to log additional
alerts. If the stuck position > commanded position, the alert is set.
T627 Econ 2 (Return) 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
S.G.L1-3) fails, an alert will be generated and the remaining
thermistors will be averaged together (Temperatures
AIR.T
matic. Reason for failure may be incorrect wiring, faulty therm-
istor, or a damaged input on the staged gas control board (SCB).
A704 (Staged Heat Lvg Air Temp Sum Total Failure)
If all three staged heat thermistors (Temperatures
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
will cause an alert to occur and a disabling of the limit switch
monitoring function for the staged gas control board (SCB). Re-
covery is automatic. Reason for failure may be 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
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. Reason for failure may
be faulty wiring, a faulty thermistor, or a damaged input on the
EXB control board.
T707 (Digital Scroll 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, 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)
MLV and Digital Scroll compressor cannot function together.
When both options are enabled, an alert will occur.
132
S.G.LS) without the failed thermistor. Recovery is auto-
AIR.T
AIR.T
AIR.T
S.G.LM)
AIR.T
CCT) installed
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Table of Contents
Troubleshooting
