Haier 1U71S2SG1FA Service Manual page 216

Control of defrosting in heating
In heating mode, defrosting temp. sensor will check the frosting condition of outdoor heat exchanger and make
defrosting control.
A: Enter condition:
Unitary: After the unit is in heating for 10 minutes and compressor run for 45 minutes in all, according to check the
defrosting temp. sensor Te and outdoor ambient temp. sensor Tao, if they can meet the following condition,
entering in defrosting operation.
o o
1. 5 C< (E) <Tao, Te<=-6 C< (E) ;
o o
2. -6 C< (E) <=Tao<=5 C, Te≤C×Tao-α;
o
Herein :α=8 (E) ; C:Tao<0
o o
3.Tao<-6 C, Te≤-15 C< (E) and defrosting compressor run for 48 minutes in all.
Multi:
a. In heating mode, if the compressor has run for 10 minutes continously and run for 55 minutes in all, the system
will measure the defrosting temperature sensor Te and outdoor ambient temp. sensor TA, if the below condition can
be met for continous 5 minutes, the unit will enter defrosting operation:
Tc≤C×TA-α
o
Herein: C: TA<0 , C=0.8 TA≥0
According to SW5-2, the setting is as follow: in the place easy to frost, it is H; when out of factory, it is M.
Jumper Selection
o
α ( C)
b. Defrosting entering condition: -15
c. Stop and Pause condition of compressor running accumulative time in heating mode:
Checking Stop: running operation changes from heating to cooling.
Checking Pause: thermostat OFF, or the unit stops.
Cancel condition:
It will take the max. 10 minutes from beginning defrosting to quit it. Te sensor will measure the condition of outdoor
heat exchanger, if the temp. is over 7
will be over.
Compulsory Defrosting Control
Enter condition: in heating mode, after receiving the compulsory defrosting signal from indoor unit, the unit will
perform the compulsory defrosting operation.
o
Cancel condition: Te≥12 C and keep for 1 minute or the defrosting time is over 10 minutes. The manual defrosting
signal of indoor unit will remain until the outdoor enters defrosting mode.
Note: When outdoor compressor not running, the unti still can enter manual defrosting, but it will comply with the
3-minute protection of compressor.
o
C; C=0.8; Tao≥0 C, C=0.6;
o
C, C=0.6
M (Out of Factory)
o o
C≤C×TA-α≤-2 C;
o
C for 60 seconds in all or is up to 12
8 (E)
o
C for 30 seconds in all, the defrosting
213
H
6 (E)