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

22 PB
OPERATION
Function and Control
Special Function
1) Advanced Settings
Fahrenheit / Centigrade display
Fahrenheit and Centigrade display mode can be switched over by holding the UP and DOWN two buttons at the
same time for 3s.
Setting Temperature Range
Hold UP and HIGH fan speed buttons at the same time for 5s, digital tube displayer will show R1—R8, default is
R8. The temperature range as the table below:
NO. SET POINT (MIN)°F SET POINT (MAX)°F
R1 63 86
R2 65 86
R3 72 90
R4 72 74
R5 67 92
R6 69 90
R7 68 72
R8 60 90
Switch Over Between 24V Remote Thermostat and Control Panel
On standby mode (unit is powered on but stays in OFF), hold the “COOL” and “UP” buttons at the same time
for 5 seconds, the digital tube will display “r” and buzzer beeps twice when it switches to 24V remote
thermostat; it will display “p” and buzzer beeps once when it switches to control panel.
Memory Function
The unit will keep the same status it was running before power down.
FD Control (front-desk control)
The unit can be turned ON/OFF by front desk control switch. The control terminal is located on the remote
thermostat interface.
Control logic:
(a). Turn ON unit: short R and FD then release one time within 5s.
(b). Turn OFF unit: short R and FD then release twice within 5s.
(c). Force unit shut down for one time: short R and FD short over 5s.
NOTE: After forced shut down, you can turn on the unit again by control panel
Protections
1) Indoor Pipe Frost Protection In Cooling Mode
When compressor has run for 12 minutes, and indoor pipe temperature ≤33°F(1°C), compressor and outdoor fan stop,
and the indoor fan keeps running. When indoor pipe temperature ≥59°F(15°C)for 5 minutes, it will quit protection
mode.
2) High Pressure Protection
When system pressure is higher than normal condition, the outdoor pipe will over heat. When outdoor pipe temp
reaches 149°F(65°C), the compressor and outdoor fan are shut down to protect. After 3 minutes, if system comes
back to normal pressure condition, unit resumes normal operation.
3) Outlet Air Overheat Protection In Electric Heating Mode
Any obstacle in the vent loop, or indoor fan failure will cause outlet air overheat in electric heating mode. To prevent
any danger, when outlet air temp reaches 154°F(68°C), the E-heater will shut down. If the temperature has reduced
after one minute, it will restart.