11-7
CONTROL SYSTEM
SM HDDHED 2-A.1 GB
11.11 Protections
There are 4 protection codes.
Normal (Norm) – unit operate normally.
Stop Rise (SR) – compressor frequency can not be raised but does not have to be decreased.
HzDown – Compressor frequency is reduced by 2Hz/s (For 9k/12k, temperature protection is
4Hz/60s)
Stop Compressor (SC) – Compressor is stopped.
11.11.1
Indoor Coil Defrost Protection
Conditions for Start Controlling
Judge the controlling start with the ICT (Indoor Coil Temperature) after 2 sec from operation start.
During cooling operation, the signals being sent from the indoor unit allow the operating frequency
limitation and then prevent freezing of the indoor heat exchanger.
Compressor frequency will be decreased or stop increasing if ICT<6C
Compressor will stop when ICT <= -1C for continuous 3 mins.
If the unit stops as such protection for 6 times, it can not resume running automatically and display
malfunction, it can resume by pressing ON/OFF.
11.11.2
Indoor Coil over Heating Protection
Conditions for Start Controlling
Judge the controlling start with the ICT after 2 sec from operation start.
During heating operation, the signals being sent from the indoor unit allow the operating frequency
limitation and prevent abnormal high pressure.
Compressor will stop when ICT/OCT reaches 62
o
C
If the unit stops as such protection for 6 times, it can not resume running automatically and display
malfunction, it can resume by pressing ON/OFF.
11.11.3
Compressor over Heating Protection
The Discharging temperature is used as the compressor’s internal temperature. If the discharge
temperature rises above a certain level, the operating frequency upper limit is set to keep this
temperature from going up further.
Compressor will stop when CTT reaches 115C
If the unit stops as such protection for 6 times, it can not resume running automatically and display
malfunction, it can resume by pressing ON/OFF.
