Components; Component Overview - Haier 2U18MS2VHB Service Manual

The Slim Duct Indoor Unit will act as evaporator coils during cooling mode and condenser coils during heating mode. This unit can
operate with a motorized supply air louver or it can have a LIMITED amount of ducting added to the unit's return and supply air
duct connection flanges. The return air ducting can be connected to the end of the cabinet or the bottom blank off plate can be
removed for bottom return configuration.
DIP Switches on the unit's circuit board configure the fan power to match the ducting configuration.
These units have a built in condensate pump with an associated condensate level switch. The condensate pump is capable of
lifting water out of the indoor unit. If high water lift is needed, the water from the cassette pump should be pumped into a field
supplied condensate pump with high lift power.
The layout of the system is very straightforward and components are easily accessed should service be required. The blower
assembly and room air temperature sensor is accessed at the rear of the evaporator coil, and the piping temperature sensor
is located under the top cover. The condensate pump and float switch are accessed under the removable panel next to the
electrical control box.
The wired controller can be configured to sense room air temperature. There is no option for use with remote control.
All operating status and information is displayed on the wired controller. The Slim Duct unit does not have a display.

Component Overview

Slim Duct units are
controlled by a wired
controller only.
1 Evaporator Coil
Blower Assembly
2
The indoor unit features a DC variable speed dual shaft
blower motor that will change speed to match the
capacity demand from the outdoor unit. The motor
is a dual shaft type that powers two individual blower
assemblies.
The blower assembly consists of 2 plastic blowers. A set
screw holds each blower wheel to the blower motor.
The indoor blower motor is connected to the indoor
unit control board. The wiring from the motor to indoor
board consists of 5 wires connected to pins that deliver
line voltage, speed, and feedback information.
During normal operation, the indoor control board will
energize the indoor blower motor and request proper
speed. Fan power should be set using the DIP Switches
SW1 settings.
F-2

Components

1
8
SLIM DUCT TECHNICAL OVERVIEW
6
2
3
Terminal Block
Power to operate the indoor unit comes from the
electrical line voltage terminal block at the outdoor unit.
The wiring includes 4 wires, 1, 2, 3 and ground. Wires 1
and 3 complete the data path. These wires should always
be 14 gauge AWG Stranded type wire. Splices in wires 1
or 3 may cause communication errors.
4
Control Board
Located under the electrical control box cover.
5
Ambient Temperature Sensor
The Ambient Temperature Sensor senses room
temperature. This sensor provides room temperature
information to the ECU for calculation of inverter
capacity and temperature control.
7
8
4
3
5