102
T610 (Economizer Actuator Out of Calibration)
A620 (IGV Actuator Out of Calibration)
T630 (Humidifier Actuator Out of Calibration)
A640 (Heating Coil Actuator Out of Calibration)
A650 (Bldg.Press. Actuator 1 Out of Calibration)
A660 (Bldg.Press. Actuator 2 Out of Calibration)
T670 (Economizer 2 Actuator Out of Calibration — Each of
the Belimo LEN communicating actuators must have a mini-
mum control range to operate. If the actuator, after a calibra-
tion, has not learned a control range appropriate for the applica-
tion, 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 Actuator Comm Failure)
A621 (IGV Actuator Communication Failure)
T631 (Humidifier Actuator Communication Failure)
A641 (Heating Coil Actuator Comm Fail)
A651 (Bldg.Press. Actuator 1 Comm Failure)
A661 (Bldg.Press. Actuator 2 Comm Failure)
T671 (Economizer 2 Actuator 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 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 (IGV 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)
T672 (Economizer 2 Actuator 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 (Econ Actuator Overload, Setpt Not Reached)
A623 (IGV Actuator Overload, Setpnt 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)
T673 (Econ2 Actuator Overload, Setpt 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 (Econ Actuator Comm Fail, Daughter Brd-MFT)
A624 (IGV Actuator Comm Fail, Daughter Board-MFT)
T634 (Humidifier Act Comm Fail, Daughter Brd-MFT)
A644 (Heat Coil Act Com Fail, Daughter Board-MFT)
A654 (BP Actuator 1 Com Fail, Daughter Board-MFT)
A664 (BP Actuator 2 Com Fail, Daughter Board-MFT)
T674 (Econ2 Actuator Comm Fail, Daughter Brd-MFT) —
Each of the actuators has an internal daughter card, which
translates communications from the LEN bus to Belimo’s MFT
(Multi-Function Technology®) communication bus and back.
If communication breaks down between the actuator and its
internal daughter card, this alarm/alert will result. This makes
the actuator unusable and any functions associated with the
particular actuator are shut down. Recovery is automatic, but
this error will probably require actuator replacement as this
problem is internal to the Belimo actuator itself.
A700 (Air Temp Lvg Supply Fan Thermistor Failure) —
The failure of this sensor will shut the system down and gener-
ate an alarm as this thermistor is a critical component to funda-
mental 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 a dam-
aged input on the staged gas control board (SCB).
A704 (Staged Gas Lvg Air Temp Sum Total Failure) — If all
three staged gas thermistors (Temperatures
→
AIR.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
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 (Temperat ures
→
AIR.T
→
CCT) installed
between the evaporator coil and the hot water coils that func-
tions 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 ECB control board.
MAJOR SYSTEM COMPONENTS
General — The 48/50Z Series package rooftop units with
electric cooling and with gas heating (48Z units) or electric cool-
ing and electric or hydronic heating (50Z Units) contain the
ComfortLink™ electronic control system that monitors all oper-
ations of the rooftop. The control system is composed of several
components as listed below. See Fig. 15-22 for typical control
and power component schematics. Figures 23-25 show the
layout of the control box.
Factory-Installed Components
MAIN BASE BOARD (MBB) — See Fig 26. The MBB is
the center of the ComfortLink control system. The MBB con-
tains the major portion of the operating software and controls
the operation of the unit. The MBB has 22 inputs and 11 out-
puts. See Table 87 for the inputs and output assignments. The
MBB also continuously monitors additional data from the
ECB, RCB, SCB, and CEM boards through the LEN commu-
nications 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® sys-
tem 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.