Functions and control 
18  Domestic air conditioner
7.1.4 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. 
7.1.5 Protection function 
7.1.5.1 TTC high temperature-preventing protection 
Once  the  machine  is  started,  it  can  run  TTC(air-blowing  temp) 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 s
ampling for 8 times, then order them and take the mean 
value of the middle 2 values), take the mean value. 
TTC
09K Abnormal stop 
107
Decreasing the frequency rapidly
1HZ/second
102 
Decreasing
 the frequency slowly (1HZ/10seconds) 
98
The frequency doesn’t change. 
95
Increasing the frequency (1HZ/10second) 
93
        Increasing the frequency
1HZ/1second
TTC>=110   lasts  for  20  seconds. Overheating  protection  of  air-blowing,  alarm  malfunction  to  the 
indoor, others don’t last. 
7.1.5.2 TC high temperature-preventing control of the indoor heating unit
Tpg_indoor is  the  highest  value  of  the  effective  indoor  unit  (start  it  and  it  is  in  accord  with  the 
running state). TC=indoor coil temp.   
The  indoor  heat  exchanger  sensor  tests  the  temperature  of  the  indoor  heat  exchanger.  If  the 
temperature  is  higher  than  63
,  decrease  the  rotate  speed  of  the  compressor  and  do  the  high 
temperature-preventing protection of the indoor heat exchanger; if the temperature of the indoor heat 
exchanger is lower than 45
, recover to the normal control.