Sharp AE-XM30GR Service Manual Download Page 10

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AE-XM30GR

2 – 2

[2] FUNCTIONS

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 fre-
quency 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 tempera-
ture 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 fre-
quency 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 approxi-
mately 108



C, the frequency is raised approximately 5Hz once

every 60 seconds, and normal operation is restored. If the fre-
quency 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 mini-
mum frequency. When the temperature of all of indoor heat
exchangers go below the overheating prevention line 1, the fre-
quency 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.

If the temperature of any of indoor heat exchangers exceeds the over-
heating prevention line 1 or 2 during heating, the operating frequency
is lowered by approximately 5 to 15Hz. After that, the frequency is low-
ered 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 fre-
quency is raised by approximately 5Hz once every 60 seconds, and
normal operation is restored. If the condition that the frequency is min-
imum lasts for 2 minutes, the compressor will be stopped.

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 com-
plete stop request signal is sent to the indoor unit, and the outdoor unit
will remain stopped until the indoor operation is stopped. DC over cur-
rent is detected by the power module. AC over current is detected by
CT1, on the outdoor PWB.

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 tem-
perature 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 out-
door unit will remain stopped until the indoor operation is stopped.

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 compressor is stopped, if the temperature is
below 85



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.

5. SERIAL SIGNALS

Serial signals consist of all 96-bit signals. If the condition as outdoor
unit unable to receive a serial signal from the indoor unit continues for
30 seconds, it closes the expansion valve which corresponds to the
room which can not be communicated. If all indoor units can not com-
municate with the outdoor unit, the compressor is stopped.

6. THERMISTOR OPEN OR SHORT

When compressor, heat exchanger, outdoor thermistor, suction ther-
mistor (CN8A) are in OPEN or SHORT condition, even if they are in
the condition which an operation signal is transmitted from indoors, the
compressor will not start. If any suction thermistors (CN8C) become
OPEN or SHORT resistance, the protective procedure will work only
for the cycle corresponding to the malfunctioning suction thermistor.

7. MISWIRING CHECK

“Mis-wiring check” is conducted by detecting the indoor heat
exchanger temp. For example, when the expansion valve for only
room A is open, and the wiring is correct, the indoor heat exchanger
temp for room A will reduce. If the wiring is incorrect, the indoor heat
exchanger temp for a different room will reduce.

8. SAFETY TIME

When the unit is operated by the remote control after the breaker is
turned on, the safety device of the compressor will work and the com-
pressor will not operate for 90 seconds.

Cooling mode

Heating mode

16.5A

Overheating Prevention line 1



Lower 5Hz once every

60 seconds

Overheating Prevention line 2



Lower 15Hz once

every 120 seconds

Overheating Prevention clear line