7
CONTROLS DESCRIPTION
Microprocessor Control Board —
The PCB (print-
ed circuit board) control board (see Fig. 4) relays control the
operation of the indoor-fan motor, outdoor-fan motor, compres-
sor 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) resis-
tive rated relays to deliver the selected indoor fan speed.
CONDENSATE PUMP — The condensate pump will acti-
vate 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 re-
lay 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. 5-13 for typical 42WKN unit wiring diagram.
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 (see Fig. 4) approximately 5 min-
utes before main power is initially applied to the unit.
Controller —
Before using the infrared transmitters, please
read this handbook fully and ensure the batteries (supplied
loose) are fitted into the IR transmitter or optional pendant.
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. 14 for controller button and icon information.
Optional Pendant —
The optional pendant (see Fig. 15)
is a hard-wired replacement for the hand-held transmitter; it
has all the functionality of the transmitter but is field-mounted
and therefore cannot be misplaced.
The pendant assembly consists of the following parts:
• Pendant controller
• Pendant wall mounting bracket
Infrared Receiver —
The IR receiver (see Fig. 16) 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 (see Fig. 4).
NOTE: Be careful not to damage the holder when changing
the battery.
Self Diagnostics —
The microprocessor controller has a
built-in diagnostics feature so that in the event of an alarm, the
nature of the fault can be determined. The red timer/alarm LED
(light-emitting diode) flashes on the fascia in a pre-determined
frequency depending on the fault as identified below:
1. Alarm LED flashes once every second: indoor coil sensor
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. 17 for explanation of
receiver indicators.
NOTE: When the microprocessor is used in a master/slave net-
work AND is configured for slave operation, both the cool and
heat indicators will be lit, even during periods when the unit is
switched off.
Fig. 4 — Microprocessor Control Board
SW
W
FH
FM
FL HP
HP
F1
0
COMP
OUT
HEAT
OUT
HEAT
IN
Compressor
Out
Compressor
In
Heat
Output
230VAC
Heater
Supply
Vane Motor
Output
Indoor Fan
3 Speeds
Reversing
Valve Out
IR Receiver
Connector
Sensor
T1 = Room Sensor
T3 = Indoor Coil
Transformer
Terminal
10A Fuse
Battery
Pendant
Connector
JMP1
JMP2
Network Terminals
For Master/Slave
Jumper Links
CPU
JMP3
T1
T1
T
2
T2
T
3
T
3
––
SS
1
R
C
COMP
IN
230VAC
230VAC
Terminal
L1
Reversing
Valve In
Condensate
Pump
L2
L2
a42-4038
