SEQUENCE OF OPERATION
PAGE 23
ENGLISH
The outdoor unit main board also controls the position of
the EEV (Electronic Expansion Valve) to regulate the ow of
refrigerant to the indoor unit evaporator coil.
Temperature Sensors
Four temperature sensors located in the outdoor unit provide
temperature information to the outdoor unit main board for
control of the system during cool mode.
The outdoor ambient temperature sensor provides the tem-
perature of the air drawn into the outdoor coil of the outdoor
unit.
The defrost temperature sensor provides the temperature
sensed at the output of the outdoor coil.
The suction line temperature sensor provides the tempera-
ture sensed at the incoming suction line pipe.
The compressor discharge sensor provides the temperature
sensed at the discharge pipe of the compressor.
Call to Terminate Cooling
The system will call to terminate cooling when the indoor am-
bient temperature sensor is equal to or lower than 2°F of the
room set temperature. The indoor control board will com-
municate to the outdoor control board to de-energize the
compressor. The outdoor fan will run for 60 seconds before
stopping.
The indoor fan motor and louver will continue operating after
cooling has been terminated.
To stop cool mode, press the power button to turn the sys-
tem o, or change to another mode.
Freeze Protection Function
To prevent freezing of the indoor unit coil during cool mode,
when the compressor operates continuously for 10 seconds
and the temperature of the indoor coil has been below 32°F
for 10 seconds, the compressor will stop, and the error will
be recorded in the malfunction list. The indoor unit fan will
continue to operate. When the temperature of the indoor coil
rises to 45°F for more than 3 minutes the compressor will
restart and the system will continue functioning.
Heat Mode
Overview
The setpoint control range in heating mode is 60°F - 86°F. The
temperature set by the remote control and the indoor unit
ambient temperature sensor will determine if a call for heat is
needed. If a call for heat is justied, a temperature compen-
sation adjustment is automatically added to the operating
parameter and the call is communicated from the indoor unit
to the outdoor unit.
The indoor unit louver will open using a stepper motor. The
indoor fan will not operate at this time.
The outdoor unit will shift the 4-way valve to the heat mode
position and determine the position of the EEV (if equipped)
and speed (frequency) of the compressor. There can be a
delay of up to 3 minutes before the outdoor unit fan and com
-
pressor start.
(Tr = room temperature Ts = set temperature)
If Tr ≤ Ts, the outdoor unit will operate and the indoor fan
operates in cold air prevention function
If Tr > Ts+, the outdoor unit turns o and the indoor fan oper-
ates at heat residue sending mode.
If Tr < Ts+, the outdoor unit will restart and the indoor fan
operates in cold air proof mode.
The speed of the indoor fan can be controlled manually by
the user or automatically by the system. The speed can be
changed between HIGH, MEDIUM, and LOW. The predeter-
mined conditions for automatic control are as follows:
High Speed: Tr < Ts
Medium Speed: Ts ≤ Tr ≤ Ts + 4°F
Low Speed: Tr > Ts + 4°F
When the indoor fan is running in automatic mode and there
is no delay when the speed switches from high to low, the
indoor fan will maintain high speed for a period of 3 minutes
before switching to low speed.
Cold Air Proof Operation
At initial start of heat mode, indoor blower will not be turned
on immediately until indoor coil temperature senses a mini-
mum temperature. This period usually takes 30 seconds to 3
minutes depending on the outdoor ambient temperature.
HSU12HG(DB)-SM Wiring Diagrams
16
Domestic Air Conditioner
*Indoor fan control
manual control: You can choose high, medium, low and automatic speed control.
Automatic: When Tr<Ts, high speed.
When Ts≤Tr≤Ts+2ć, medium speed.
When Tr> Ts+2ć, low speed.
When the airflow speed has no delay from the high to low switching, the speed should be delayed for
3 minutes (remain at high speed for 3 minutes.) before the next switch.
*Airgate location control: the location for the airgate can be set according to your needs.
Coldair proof operation
1. The indoor operation within 4 minutes after the start up is as the following diagram, the air speed
can be raised only after the speed has reached a certain level.
2. 4 minutes after the start up of the indoor fan, the light airflow and the low airflow will be turned to the
set speed airflow.
3. In the cold air proof operation, the fan won’t stop after the start up.
4. During the cold air proof operation, the indoor system will continuously send ‘indoor high speed’
signals to the outdoor system.
* Residue heat sending. The indoor fan will send the residue heat at a low speed for 12 seconds.
If other conditions are satisified, when the compressor stops, the indoor system will operate at a light
speed. The indoor fan will stop when the coil temperature is below the ‘heat start temp 4’.
* Defrosting. When the system receives the defrosting signal from outdoors, the indoor fan will stop
and the indoor temperature display won’t change. At the time, any indoor coil malfunctions will be
neglected. When the outdoor defrosting finishes, the coil malfunction will still be neglected until the
compressor has been started up for 30 seconds. The indoor temperature display will not change and
the system operates at the cold air proof mode.
* Automatic heating temperature compensation: when the system enters the heating mode, the
temperature compensation (4) will be added. When the status is switched off, the compensation will
be erased.
Heat start temp 1
Heat start temp
2
Heat start temp
3
Heat start temp
4
Low speed
Light speed
Fan/off
Fan/off
Keep the hig
speed. The fa
doesn’t stop
4 minutes after the indoor fan starts, the light or low speed
will switch to the set speed.
In cold air proof operation, the fan remains on after startup.
Residual heat sending: The indoor fan will operate on low
speed for 12 seconds.
Outdoor unit temperature sensors: Outdoor ambient,
defrost, suction line, and compressor discharge, used in
conjunction with the indoor temperature sensors, indoor
ambient and tube, provide information to the outdoor control
board to monitor the system and regulate the frequency of
the compressor, EEV positioning, and outdoor fan speed to
achieve the desired room temperature.
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