HSU12HG(DB)-SM    Wiring Diagrams
24 
Domestic Air Conditioner
5.2.3˖The control of the outdoor electronic expansion valve 
When starting the compressor: the opening size of the valve must be guaranteed to have entered into 
the standard opening size, and then the compressor can be started.   
When refrigeration is in vain (the machine is shut down or is in the state of retrograde operation), the 
opening size of the expansion valve of the indoor unit is 5 steps;   
When heating is in vain, the opening size of the expansion valve of the indoor unit is 55 steps;   
When the outdoor unit is shut down, the valve is opened completely for 2 minutes, and then begin 
initialization.  
The scope of refrigerationg valve      90-----480 steps 
The scope of heating valve        80-----480 steps 
The valves are adjusted according to the degree of superheat —SHaˈƸSHa. 
 
 
5.2.4˖Four way control 
For the details of defrosting four-way valve control, see the defrosting process.   
Four way working in other ways: 
Under the mode of heating, open the four-way valve, when the compressor is not started or changed 
to non-heating mode, make sure the compressor is stoped for 2 minutes, and then close the four-way 
valve.  
 
 
5.2.5  ˖Protection function 
5.2.5.1˖TTC high temperature-preventing protection 
Once the machine is started, it can run TTC overheating protection of air-blowing, but air-blowing 
sensor malfunction must alarm after 4 minutes during which the compressor is started (during the 
course of self-detection, there’s no such limitation)   
Sensor detection methods: 100 times (one cycle of procedure run is one time, and about 5ms, 
detection method for each time: continuously sampling for 8 times, then order them and take the 
mean value of the middle 2 values), take the mean value.   
TTC˄ć˅ 
      Abnormal stop 
    110 
      Decreasing the frequency rapidly˄1HZ/second˅ 
    100 
      Decreasing the frequency slowly (1HZ/10seconds) 
    98 
      The frequency doesn’t change.  
    93 
      Increasing the frequency (1HZ/10second) 
    90 
      Increasing the frequency˄1HZ/1second˅ 
TTC>=110ć lasts for 20 seconds. Overheating protection of air-blowing, alarm malfunction to the 
indoor, others don’t last.