AE-XM24CR (serv.man8). Functions - Sharp Air Conditioner Service Manual (repair manual). Page 8

38

2-1 FREQUENCY CONTROL
(1) AC current peak control

Cooling MODE

Heating MODE

14.0A

14.0A

(2) Prevention control of outdoor heat exchanger

overheating
If the temperature of the outdoor heat exchanger
exceeds the overheating 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.

Overheating Prevention line 1

Overheating Prevention line 2

Lower 5Hz once every 60 seconds

Lower 15Hz once every 120 seconds

Overheating Prevention clear line

55˚C

57˚C

54˚C

(3) Prevention control of compressor overheating

If the temperature of the compressor exceeds
approximately 108ÅãC, 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 108ÅãC, 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

< for 2 minutes since 2room ON 1room ON >
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 1 min, the compressor will be stopped.

< when normal >
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 1 min, the compressor will be stopped.

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.

The set value of AC current

16.0A

Cooling mode

Heating mode

16.0A

When 
ON

When 
OFF

Overheat 
prevention line 2

Overheat 
prevention line 1

Overheat 
prevention line 2

Overheat 
prevention line 1

~ 25Hz

25 ~ 
35Hz

35 ~ 
95Hz

95Hz ~

47.0˚C

45.0˚C

60.0˚C

57.0˚C

54.0˚C

52.0˚C

63.0˚C

59.0˚C

56.0˚C

54.0˚C

64.0˚C

60.0˚C

55.0˚C

53.0˚C

62.0˚C

58.0˚C

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 99ÅãC.
In 90 seconds after the compressor is stopped, if the
temperature is below 90ÅãC, 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.