131
SCROLLING MARQUEE
This device is the keypad interface used to access the control
information, read sensor values, and test the unit. The scrolling
marquee display is a 4-key, 4-character, 16-segment LED dis-
play as well as an Alarm Status LED. See Fig. 35. The display
is easy to operate using 4 buttons and a group of 11 LEDs that
indicate the following menu structures:
• Run Status
• Service Test
• Temperatures
• Pressures
• Setpoints
• Inputs
• Outputs
• Configuration
• Timeclock
• Operating Modes
• Alarms
Through the scrolling marquee the user can access all the in-
puts and outputs to check on their values and status. Because
the unit is equipped with suction pressure transducers and dis-
charge saturation temperature sensors it can also display pres-
sures typically obtained from gages. The control includes a full
alarm history, which can be accessed from the display. In addi-
tion, 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
Com-
fort
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
removable panel as shown in Fig. 28 and 29. 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 in-
verter has a display, which can be used for service diagnostics,
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. 36. Terminal designations
are shown in Table 108.
Table 108 — VFD Terminal Designations
POWER EXHAUST
The units can be equipped with an optional power exhaust sys-
tem. The power exhaust fans are forward-curved fans with di-
rect-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 methods. For CV applications
the fans can be configured for 2 stages based on adjustable
economizer damper positions. For VAV applications and CV
units with the building pressure control option, the fans are se-
quenced 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 econo-
mizer motor controls their position. The motor position is con-
trolled by the ECB1 board by means of a digital two-way com-
munication signal. This allows for accurate control of the mo-
tors as well as feedback information and diagnostics
information. The control has a self-calibration routine that al-
lows 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.
Fig. 35 — Scrolling Marquee
Run Status
Service Test
Temperature
Pressures
Setpoints
Inputs
Outputs
Configuration
Time Clock
Operating Modes
Alarms
Alarm Status
ENTER
MODE
ESCAPE
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
Summary of Contents for WEATHERMAKER 48A2020
Page 112: ...112 Fig 20 Typical Main Control Box Wiring Schematic 48 50A Units ...
Page 113: ...113 Fig 21 Typical Auxiliary Control Box Wiring Schematic ...
Page 114: ...114 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown ...
Page 115: ...115 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown TO NEXT PAGE ...
Page 116: ...116 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont ...
Page 117: ...117 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown ...
Page 118: ...118 Fig 25 Typical Controls Option Wiring Schematic SW1 SW2 OR DEHUMIDIFY SWITCH ...
Page 119: ...119 Fig 26 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown ...
Page 120: ...120 Fig 27 Typical Power Schematic of Greenspeed Low Ambient Option 48 50A 060 Unit Shown ...
Page 121: ...121 Fig 28 Typical Small Chassis Component Location Size 020 035 Units ...
Page 122: ...122 Fig 29 Typical Large Chassis Component Locations Size 040 060 Units ...
Page 185: ...185 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716 ...