Multi-Zone Technical Overview

TECHNICAL OVERVIEW
PAGE 37
ENGLISH
The blower assembly consists of a plastic blower wheel that
is connected to a variable speed indoor blower motor. A set
screw holds the blower wheel to the blower motor.
The indoor blower motor is a DC Fan Motor that is
connected to the indoor unit control board via Plug CN-9.
The wiring from the motor to indoor board consists of 5 wires
connected to pins 1, 4, 5, 6 and 7. Pin 1 should have 310 VDC.
Pin 4 is ground. Pin 5 +15VDC. Pin 6 is the feedback signal. Pin
7 is the speed control.
During normal operation, the indoor control board will
energize the indoor blower motor and request proper speed.
The indoor blower motor will control the speed via a command
at the Pin 7 speed control. Proper fan speed is veried by the
indoor control board via the voltage level at the feedback
signal on Pin 6. Should the feedback signal not be present
during a call for indoor blower, the indoor control board will
indicate a Malfunction Code E14.
Louver motors
The louver motors are stepper type motors that move
the louvers either right/left or up/down. The motors are
controlled by pulsed voltage that cannot be measured. If the
louver does not move when it should, check for a blockage
in the louvers. If the louver is free to move, refer to the Test
Procedure Section.
See A and B below.
INDOOR WALL MOUNT UNIT TECHNICAL OVERVIEW
Blower Assembly
Indoor Ambient
Temperature Sensor
Indoor Pipe Sensor
Temperature Sensors
The Piping Temperature Sensor senses indoor coil
temperature in the cooling mode and in the heating mode.
This sensor is used for Anti Freezing and Anti Cold Blow cycles.
The sensor also provides critical temperature information
to the ECU that may be used in frequency adjustments. See
Temperature Sensor Functions.
The Ambient Temperature Sensor senses room
temperature. This sensor provides room temperature
information to the ECU for calculation of inverter capacity and
temperature control.
Both sensors are negative temperature coecient type that
reduce electrical resistance as temperature rises.
B
A