7
CONTROLS DESCRIPTION
Microprocessor Control Board
The PCB (printed circuit board) control board relays control
the operation of the indoor-fan motor, outdoor-fan motor,
compressor and electric heater (if fitted), to maintain room
conditions at a user-defined set point. Temperature settings,
fan speeds and other control functions can be changed by the
infrared (IR) transmitter or optional pendant. The controller
PCB provides the following input/output facilities:
Inputs
• T1 Return Air Temperature Sensor: 50K at 77°F
• T3 Indoor Coil Temperature Sensor: 50K at 77°F
Outputs
INDOOR FAN MOTOR
The controller will switch a combination of three 10 amp,
230-vac (3 speed settings) resistive rated relays to deliver the
selected indoor fan speed.
CONDENSATE PUMP
The condensate pump will activate when unit is in cooling
mode.
VANE MOTOR
A 10 amp, 230-vac resistive rated relay switches the vane
motor on when Air Sweep is selected (unit sizes 18-36 only).
ELECTRIC HEAT
A 30 amp, 230-vac resistive rated relay switches the electric
heater on when required.
External Connections
• Power input - Nominal 230-vac, 50/60 Hz
• Network connection - Twisted pair shielded cable
Refer to Fig. 5-34 for typical 42WKN unit wiring diagrams.
Microprocessor PCB Battery (P/N CR2032)
The microprocessor PCB is fitted with a battery backup system
that maintains the CPU (central processing unit) memory and
time clock settings during brief power outages. The battery is
small, round and silver in appearance, similar to a wrist watch
battery. When the unit is shipped, the battery is packed in a
plastic bag and is placed inside the small rectangular box con-
taining the infrared transmitter. The battery should be installed
into the PCB's battery holder approximately 5 minutes before
main power is initially applied to the unit.
Controller
Before using the infrared transmitters, please read this hand-
book fully and ensure the batteries (supplied loose) are fitted
into the IR transmitter.
A microprocessor mounted in a metal control box enclosure
is used to control the entire unit operating functions with
adjustments and settings being made from a hand-held IR
transmitter or optional pendant.
The controls include the following basic components:
• PCB control board
• Infrared transmitter or optional pendant
• Infrared receiver (fascia)
See Fig. 35 for controller button and icon information.
Infrared Receiver
The IR receiver (see Fig. 36) is an extension of the control
board and is located on the fascia of the unit, connected by a
7-pin plug and socket.
The green on/off indicator will be illuminated when the unit
is running.
Yellow indicators show the present unit status, either “cool”
or “heat.”
When both yellow indicators flash, the PCB control board
battery needs to be changed.
NOTE: Be careful not to damage the holder when changing the
battery.
Self Diagnostics
The microprocessor controller has a built-in diagnostics fea-
ture so that in the event of an alarm, the nature of the fault can
be determined. The red timer/alarm LED (light-emitting di-
ode) flashes on the fascia in a pre-determined frequency de-
pending on the fault as identified below:
1. Alarm LED flashes once every second: indoor coil sen-
sor failure, low coil temperature or condensate high level
trip.
2. Alarm LED flashes once every 5 seconds: return air sen-
sor failure.
Receiver Indicators
See Fig. 36 on page 38 and “Operation” on page 54 for an ex-
planation of receiver indicators.