Service and Parts Manual (2018, 2019, 2020, 2021, 2022)

20 PB
OPERATION
Function and Control
Buttons and Display
1) Buttons
There are ON/OFF, UP, DOWN, HEAT, COOL, CONSTANT FAN and fan speed of HIGH, LOW, AUTO buttons.
1. ON/OFF: Press to turn power on or off to the unit.
2. COOL, HEAT: choose the mode of operation
3. HIGH, LOW, AUTO: choose the fan speed.
4. UP, DOWN: Adjust the setting temperature , default: 60-90°F(16~32°F).
2) Dual 8 Digital Tube Displayer and LED
Two 8 digital tube and 7 LEDs (ON/OFF, HIGH, LOW, AUTO, HEAT, COOL, CONSTANT FAN)
1. Mode LED display: when the unit is running in a certain mode, the corresponding LED is lit up.
2. ON/OFF LED: at ON status, the LED is lit up.
3. CONSTANT FAN LED: when this function is enabled, the LED is lit up.
4. Fan speed LED: when the unit is running at HIGH, LOW or AUTO fan speed, the corresponding LED is lit up.
5. Dual 8 digital tube displayer: normally, it displays the indoor ambient temperature. When the UP/DOWN
button is pressed it displays the setting temperature. If an error occurs, it displays the ERROR.
CODE (See table below).
The LED close to the button indicates the current status (lit up means effective).
ERROR CODE TABLE:
"E2" Indoor ambient temp sensor is open circuit or short circuit
"E3" Indoor pipe temp sensor is open circuit or short circuit
"E4" 1.Indoor vent outlet temp sensor is open circuit or short
circuit
2.Outlet air overheat in Electric heating mode
"E5" Outdoor pipe temp sensor is open circuit or short circuit
"E8" 1.Frost protection in cooling
2.Indoor pipe overheat protection in heat pump"
"E9" High pressure protection
Temperature Parameter
Indoor setting temperature (Ts)
Indoor ambient temperature (T1)
System Basic Function
Once the compressor starts, the compressor won’t stop with the change of the indoor temperature. Once the
compressor stops, it can only start after a 3 mins delay. (The compressor can stop immediately at the time of mode
switchover, turning off the unit, adjusting setting temperature and turning off from a function error.)
1) Cooling Mode
Working conditions and process for cooling:
When T1≥Ts+2°F(1°C), the unit is running in cooling mode. Meanwhile, the compressor is running and the fan is
running at the setting fan speed;
When T1≤Ts-2°F(1°C), the compressor is OFF. Meanwhile, the fan will run at the setting fan speed for 15s (CONSTANT
FAN OFF); or run at the setting speed continuously (CONSTANT FAN ON);
When Ts-2 2°F(1°C)<T1<Ts+ 2°F(1°C), the unit keeps previous running status.