Protection Functions - Haier AW09EH2VHD Service Manual

Tempe T T rature Sensors
Four temperature sensors located in the outdoor unit provide
information to the outdoor unit PCB for control of the system
The outdoor ambient temperature sensor provides the
temperature of the air drawn into the condenser c
The defrost temperature sensor provides the temperature
sensed at the output of the condenser c
The suction line temperature sensor provides the tempera-
ture sensed at the inc
The compressor discharge sensor provides the temperature
sensed at the discharge pipe of the compr
To stop dry mode, press the power button to turn the system
o , or change to ano
Defrost Operation
Defrost cycle will initiate if any of three conditions are met:
Te = Defrost temperature sensor
Tao = Outdoor ambient temperature sensor
Tes = Condensation point temperature
Tes = C X Tao-a
To enter the defrost mode, the compressor must have acc-
When the defrost cycle begins, the following conditions take
place:
The system will exit the defrost cycle if any of the following
conditions are met:
PAGE 24
Upon exiting the defrost cycle, the following conditions will
take place:
1. Compressor High Temperature
The compressor discharge pipe sensor (exhaust temp)
senses the temperature of the refrigerant exiting the compressor
The sensed temperature received from the sensor
by the control circuitry will cause the compressor fr f f equency
to increase or decrease (see chart below If a temperature
of >= 23 f
protection error code will be indicated at the outdoor unit
TTC
°F
212
°F
°F
°F
°F
2. Overheating Protection for Indoor Unit
sensor monitors coil temperature in both heating and cooling
modes, and causes the compressor to speed up, slow down, or
SEQUENCE OF OPERATION

Protection Functions

°F is sensed fo f f seconds, an exhaust overheating
(°F)
stop
Decreasing the frequency rapidly (1HZ/1second)
Decreasing the frequency slowly (1HZ
The frequency doesn't change
Increasing the frequency (1HZ
Increasing the frequency (1HZ/1second)
f f
conds)
conds)