AEXM24HR
2 – 2
[2] FUNCTION
1. OUTDOOR UNIT
1.1. FREQUENCY CONTROL 
(1) AC current peak control 
(2) Prevention control of outdoor heat exchanger overheating 
      If the temperature of the outdoor heat exchanger exceeds the 
      over heating  prevention line 1or 2 during cooling, the operating 
      frequency is lowered by approximately 5 to 15Hz. 
      After that, the frequency is lowered 
     approximately 5Hz once every 60 seconds or approximately 15Hz
     once every 120 seconds. 
     When the temperature of the outdoor heat exchanger goes below      
     the overheating 
     prevention clear line, the frequency is raised by approximately 5Hz  
     once every 60 seconds, and normal operation is restored. 
     If the frequency is lowered to minimum frequency without the
     temperature of the outdoor heat exchanger decreasing and this 
     condition   lasts for 1 minute, the compressor will be stopped.
 
(3) Prevention control of compressor overheating If the temperature 
      of the compressor exceeds approximately 108°C the operating
      frequency is lowered approximately 5Hz. 
      After that, the frequency is lowered approximately 5Hz once  every
      60 seconds. 
      When the compressor temperature drops below approximately  
      108°c, the frequency is raised 
      approximately 5Hz once every 60 seconds, and normal operation
       is restored. 
      If the frequency is lowered to minimum frequency without the
       temperature of the compressor decreasing,and this condition lasts
       for 1 minute, the compressor will be stopped. 
(4) Prevention control of indoor heat exchanger overheating 
     Two minutes after room several decrease If the temperature of any 
     of indoor heat exchangers  exceeds the overheating prevention line
     1 or 2 during heating, the operating frequency is lowered to
     minimum frequency.
     When the temperature of all of indoor heat exchangers go below
     the overheating prevention line 1, the frequency is raised by 
     approximately 5Hz  once every 60 seconds, and normal operation 
     is restored.
     If the condition that the frequency is minimum lasts for 2 minutes,
     the compressor will be stopped. 
 <when nomal>
     if the temperature of any of indoor heat exchangers exceeds  the
     overheating prevention line 1 or 2 during heating, the operating 
  frequency is lowered by approximately 5 to 15Hz.
  After that , the frequency is lowered approximately 5Hz once every 
  60 seconds or approximately 15Hz once every 90 seconds.
  When the temperature of all of indoor heat exchangers go below the
  overheating prevention line 1, the frequency is raised by 
  approximately 5Hz once every 60 seconds, and normal operation is 
  restored. 
  If the condition that the frequency is minimum lasts for 2 minutes, the
  compressor will be stopped. 
1.2. OVER CURRENT PROTECTION 
    DC over current detection, AC over current detection
    To protect against over current due to sudden change in load,the 
    compressor is stopped if 55A DC is exceeded in the DC section. 
    If the set value of AC current is exceeded in the AC section, the 
    compressor is stopped. 90 seconds after the compressor has been 
    stopped, another starting try will be made. 
    Three retries are allowed. On the fourth retry, a complete stop 
     request signal is sent to the indoor unit, and the outdoor unit will
     remain stopped until the indoor operation is stopped. 
     DC over current is detected by the power module.
     AC over current is detected by CT1 on the outdoor PWB.
1.3. COMPRESSOR PROTECTION CONTROL
   If the temperature of the compressor exceeds 113°C the compressor 
    is stopped. 
    In this case, the outdoor fan is not stopped until the temperature of 
    compressor drops below 99°C.In 90 seconds after the 
    compressor  is stopped, if the temperature is below 90°C another
    starting try will be made. Three retries are allowed. 
    On the fourth retry, a complete stop request signal is sent to the 
    indoor unit, and the outdoor unit will remain stopped until the indoor 
    operation is stopped. 
1.4. POWER TRANSISTOR MODULE PROTECTION 
     If the temperature of the chips in the power transistor module
     exceeds 100°C,the compressor is stopped.
     In this case, the outdoor fan is not stopped until the temperature of 
     power module drops below 85°C. In 90 seconds after the 
Cooling mode  Heating mode 
AE-XM24HR 16.5A 16.5A
Overheating Prevention 
line 1
55°C Lower 5Hz once every 60 
seconds
Overheating Prevention line 
2
57°C Lower 15Hz once every 120 
seconds
Overheating Prevention 
clearline
54°C
Cooling mode Heating mode
AE-XM24HR 19.3A 19.3A
When ON
(When OFF)
Overheating
prevention
line 1
900
44
(57
)
54
48
51
57
47
(60 )
2100 5200 7200
Overheating
prevention line 2
When ON
(When OFF)
Overheating
prevention
line 1
900
44
(57
54
48
51
57
47
(60
2100 5200 7200
Overheating
prevention line 2
(62 )(6
(59 )
(57 )
(54 )