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

15 PB
OPERATION
Sequence of Operation
Main function
NOTES:
RT------Room Temperature.
IC------Indoor CoilTemperature.
ST------indoor Set Temperature.
OC---Outdoor Coil Temperature.
CRT---Compensated Room Temperature
1. Cooling mode
In the cooling mode, COOL indicator is ON, the set temperature and fan speed could be changed or adjusted.
a. When RT-ST≥ 1.8°F the compressor operates if there is not any protection or failure happened.
b. When RT-ST< 1.8°F the compressor stops, and fan motor keeps operation continuous.
c. When 1.8°F ≤RT-ST<1.8°F the compressor keeps former status.
1.1 Indoor fan motor control
1.1.1 Indoor fan motor can be controlled by Auto, Low, Med and High speed.
1.1.2 Indoor fan motor Auto control as below:
a) In cooling mode T=RT-ST
b) While T<0°F, operates in low speed;
c) If T= 3.6°F, in medium speed
d )If T≥7.2°F , in high speed
e) If 3.6°F < T < 7.2°F , The fan motor runs at original speed while it was set in High or Med mode. If original
at Low speed, it will change to Med speed automatically.
f) If 0°F ≤ T < 3.6°F, , The fan motor operates at original speed while it was set in Low or Med mode. If
original at High speed, it will change to Med automatically.
g) When fan speed changes due to the temperature variation, it could be changed only by sequence as High,
Med to Low speed or Low, Med to High speed, and each status will keep at least 2 minutes.
Temperature drop Temperature Rise
7.2
°
F
High speed
3.6
°
F
Medium Speed
0
°
F
Low Speed
3.6° F
7.2°F
Auto fan speed in cooling mode