124
discharge saturation temperature sensors it can also display
pressures typically obtained from gages. The control includes a
full alarm history, which can be accessed from the display. In
addition, through the scrolling marquee the user can access a
built-in test routine that can be used at start-up commission and
to diagnose operational problems with the unit. The scrolling
marquee is located in the main control box and is standard on
all units.
SUPPLY FAN — The size 020 to 050 units are equipped with
two 15 x 11-in. forward-curved fans. The size 060 units have
three 15 x 11-in. fans. They are on a common shaft and are
driven by single belt drive 3-phase motor. The fan is controlled
directly by the
Comfort
Link
controls.
VARIABLE FREQUENCY DRIVE (VFD) — On variable
volume units, the supply fan speed is controlled by a 3-phase
VFD. The VFD is located in the fan section behind a remov-
able panel as shown in Fig. 27 and 28. The VFD speed is
controlled directly by the
Comfort
Link controls through a 4 to
20 mA signal based on a supply duct pressure sensor. The
inverter has a display, which can be used for service diagnos-
tics, but setup of the supply duct pressure setpoint and control
loop factors is done through the scrolling marquee display. The
VFD is powered during normal operation to prevent condensa-
tion from forming on the boards during the off mode and is
stopped by driving the speed to 0 (by sending a 2 mA signal to
the VFD).
The A Series units use ABB ACH550 VFDs. The interface
wiring for the VFDs is shown in Fig. 35. Terminal designations
are shown in Table 109.
Table 109 — VFD Terminal Designations
POWER EXHAUST — The units can be equipped with an
optional power exhaust system. The power exhaust fans are
forward-curved fans with direct-drive motors. The motors are
controlled directly by the
Comfort
Link controls through the
ECB1 board. On the 48/50A020-050 units there are 4 fans. On
the 48/50A 060 units there are 6 fans. The fan sequences are
controlled to provide 4 stages on the 48/50A020-050 units and
6 stages on the 48/50A 060 units. There are two control meth-
ods. For CV applications the fans can be configured for 2 stag-
es based on adjustable economizer damper positions. For VAV
applications and CV units with the building pressure control
option, the fans are sequenced to maintain a building pressure
setpoint based on a building pressure transducer.
ECONOMIZER MOTOR — The economizer outside air and
return air dampers are gear-driven dampers without linkage. A
digitally controlled economizer motor controls their position.
The motor position is controlled by the ECB1 board by means
of a digital two-way communication signal. This allows for
accurate control of the motors as well as feedback information
and diagnostics information. The control has a self-calibration
routine that allows the motor position to be configured at initial
unit start-up. The motor is located on the economizer and can
be reached through the filter access door.
Run Status
Service Test
Temperature
Pressures
Setpoints
Inputs
Outputs
Configuration
Time Clock
Operating Modes
Alarms
Alarm Status
ENTER
MODE
ESCAPE
Fig. 34 — Scrolling Marquee
A30-2239
TERMINAL
FUNCTION
U1
V1
W1
Three-Phase Main Circuit Input Power Supply
U2
V2
Three-Phase AC Output to Motor, 0 V to
W2
Maximum Input Voltage Level
X1-11 (GND)
X1-12 (COMMON)
Factory-supplied jumper
X1-10 (24 VDC)
X1-13 (DI-1)
Run (factory-supplied jumper)
X1-10 (24 VDC)
Start Enable 1 (factory-supplied jumper). When
X1-16 (DI-4)
opened the drive goes to emergency stop.
X1-2 (AI-1)
X1-3 (AGND)
Factory wired for 4 to 20 mA remote input
Fig. 35 — VFD Wiring
+
–
A48-7709
Содержание Carrier Weathermaker 48A2
Страница 105: ...105 Fig 20 Typical Main Control Box Wiring Schematic 48 50A2 A3 A4 A5 Units...
Страница 106: ...106 Fig 21 Typical Auxiliary Control Box Wiring Schematic...
Страница 107: ...107 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown a48 8357...
Страница 108: ...108 TO NEXT PAGE Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown A48 7296...
Страница 109: ...109 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont A48 8358...
Страница 110: ...110 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown a50 8228...
Страница 111: ...111 Fig 25 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown...
Страница 112: ...112 Fig 26 Typical Low Ambient Controls Option Wiring...
Страница 113: ...113 Fig 27 Typical Small Chassis Component Location Size 020 035 Units...
Страница 114: ...114 Fig 28 Typical Large Chassis Component Locations Size 040 060 Units...
Страница 118: ...118 Fig 30 Economizer Control Board ECB1 and VAV Control Board ECB2 A48 7706...
Страница 142: ...142 A48 3733 Fig 56 Main Burner Removal...
Страница 176: ...176 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716...
