Dry Mode; Heating Mode; 4-Way Valve Control; Defrosting Function - Hyundai HSH-I073NBE Service Manual

3, Dry mode

running into this mode, the Air cond. firstly operates for 3 minutes according to cooling mode (set
temperature is 7℃) , and then takes the detected backflow air temperature minus 2℃ as a new set
temperature (the minimum value of 5℃) and runs according to cooling mode, indoor fan operates at
low-speed, at this moment the setting operation of Fan speed is invalid but Swing is adjustable.

4. Heating mode

On the Heating mode, the room temperature is repaired. After repaired, the room temperature
display on the LED CRT=RT-3℃.
1) The control of the compressor
a. When ST－CRT≥1℃，the compressor is running.
b. When ST－CRT＜-1℃，the compressor is off.
c. When -1℃≤ST－CRT＜1℃, the compressor keeps its original state
2) Outdoor fan motor and the compressor run simultaneously (except for defrosting)
3) The control of indoor fan motor:
a. Indoor fan motor can operate by automatic, low, middle, and high airflow speed circularly.
b. indoor fan motor's the automatic airflow speed control Indoor fan motor can operate by automatic，
as shown in Figure 2:
Hi
Mid
Lo
ST－CRT
When the temperature changes lead to changes in airflow speed, the switch can only be made
orderly, and every grade of air flow speed runs 1 minute at least.
4) Vane motor control: run as set state.

5) 4-way valve control:

a. Under heating mode, the four-way valve maintains well-connected status (including the
compressor stops on set condition, but except for the defrosting process)
b. When the mode switches into the heating mode or start-up, four-way valves will open 5 Seconds
before the compressor starts; while the mode exits from the heating mode or turn off, the four-way
valve will close 2min after after the shut-down the compressor.

6) Defrosting function:

During defrosting, once mode switch, temperature setting signals received, and the buzzer and
display make response immediately, but the other operations won't implemented until defrosting
finished;
During defrosting, the signals of on-off, timing, sleep, airflow speed ans swing will be responded, but
the airflow speed and swing should be in accordance with anti-cold air rules.
Except the above signal processing during defrosting, no other signals will be dealt with, but only a
loud buzz.
During defrosting, electrical heating stops compulsively.
Defrosting enter and exit pragram:
Option 1：with jumper JC
The condition of enter defrosting: run into defrosting once any of condition 1, 2, and 3 met.
Air Conditioner Service Manual
Figure 2 Heating automatic airflow
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1℃ 2℃ 4℃