Controls, Start-Up, Operation, Service and ... - Climayoreo

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
operation, 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
changing too rapidly. Recovery 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 (TemperaturesAIR.TS.G.L1-3)
fails, an alert will be generated and the remaining thermistors
will be averaged together (TemperaturesAIR.TS.G.LS)
without the failed thermistor. Recovery is automatic. Reason
for failure may be incorrect wiring, faulty thermistor, or a damaged
input on the staged gas control board (SCB).
A704 (Staged Gas Lvg Air Temp Sum Total Failure) — If all
three staged gas thermistors (TemperaturesAIR.T
S.G.L1,2,3) fail, staged gas will be shut down and this alarm
will be generated. Recovery is automatic. Reason for failure
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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 (TemperaturesAIR.TS.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 (TemperaturesAIR.TCCT) installed
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 due to 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 discharge
temperature thermistor, the alarm is generated. The thermistor
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.
MAJOR SYSTEM COMPONENTS
General — The 48/50P Series package rooftop units with
electric cooling and with gas heating (48P units) or electric cooling
and electric or hydronic heating (50P Units) contain the
ComfortLink electronic control system that monitors all operations
of the rooftop. The control system is composed of several
components as listed below. See Fig. 19-25 for typical control
and power component schematics. Figures 26-28 show the
layout of the control box.
Factory-Installed Components
MAIN BASE BOARD (MBB) — See Fig 29. The MBB is
the center of the ComfortLink control system. The MBB contains
the major portion of the operating software and controls
the operation of the unit. The MBB has 22 inputs and 11 outputs.
See Table 92 for the inputs and output assignments. The
MBB also continuously monitors additional data from the
EXB, RXB, SCB, and CEM boards through the LEN communications
port. The MBB also communicates with and controls
the actuator motors, economizer, power exhaust dampers,
VFDs, IGVs, hydronic valves, and humidifier valves. The
MBB also interfaces with the Carrier Comfort Network ® system
through the CCN communications port located on the
COMM3 board. The COMM3 board has permanent terminals
as well as a J11 jack for temporary connections. The board is
located in the main control box.