16
AH-S327W2
AU-S327W2
2. OUTDOOR UNIT
2-1 Frequency control
(1) AC current peak control
This control lowers the compressor frequency if the AC
current exceeds the set values. If the current is below
the set values, the compressor frequency will not be
raised above that frequency, as the maximum
frequency, for 1 minute.
AU-S327W2
Model
Set value
Approximately 10.4 A
(2) Control for prevention of outdoor heat exchanger
overheating
If the temperature of the outdoor heat exchanger
exceeds approximately 57
°
C during cooling, the
operating frequency is lowered by approximately 5 to 15
Hz. After that, the frequency is lowered by
approximately 5 to 10 Hz once every 120 seconds.
When the temperature of the outdoor heat exchanger
goes below approximately 55˚C, the frequency is raised
by approximately 5 Hz 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) Control for prevention of discharge overheating
If the discharge temperature exceeds approximately
105 ~ 107
°
C during compressor operation, the
operating frequency is lowered by approximately 5 Hz.
After that, the frequency is lowered by approximately 5
Hz once every 60 seconds. When the temperature of
the outdoor heat exchanger goes below approximately
104 ~ 106˚C, the frequency is raised by approximately 5
Hz once every 60 seconds, and normal operation is
restored.
If the frequency is lowered to minimum frequency
without the discharge temperature decreasing and this
condition lasts for 1 minute, the compressor will be
stopped.
(4) Control for prevention of indoor heat exchanger freezing
If the temperature of the indoor heat exchanger goes
below approximately 5
°
C during cooling, the operating
frequency is lowered by approximately 5 Hz. After that,
the frequency is lowered by approximately 5 Hz once
every 60 seconds. When the temperature of the indoor
heat exchanger rises above approximately 5
°
C, the
frequency is raised by approximately 5 Hz once every
60 seconds, and normal operation is restored.
If the temperature of the indoor heat exchanger goes
down to approximately 0
°
C and this condition continues
for 4 minutes, the compressor is stopped. When the
temperature rises above approximately 2˚C, normal
operation is restored.
2-2 Overcurrent protection
(1) Compressor lock detection
If the set value (4.25 A) of AC current is exceeded at 17
to 30 Hz when operation begins, operation is stopped.
In this case, the compressor outdoor fan does not stop,
and 170 seconds after operation is stopped, another 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 reset is performed. At this time, the 3-minute delay
for control of the outdoor unit will not function; therefore,
do not cancel by removing the plug and cutting the
power.
(2) DC overcurrent detection, AC overcurrent detection
To protect against overcurrent due to sudden changes
in load, the compressor is stopped if the set value 30 A
DC is exceeded in the DC section, or the set value 15 A
AC is exceeded in the AC section. In this case, the
outdoor fan does not stop, and 170 seconds after
operation is stopped, another 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 reset is performed. At this
time, the 3-minute delay for control of the outdoor unit
will not function; therefore, do not cancel by removing
the plug and cutting the power.
2-3 Compressor protector control
If the temperature of the compressor chamber exceeds
114
°
C, the compressor is stopped. In this case, the
outdoor fan does not stop, and when the compressor
chamber temperature decreases to 100
°
C three
minutes after operation is stopped, another 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 reset is
performed. At this time, the 3-minute delay for control of
the outdoor unit will not function; therefore, do not
cancel by removing the plug and cutting the power.
2-4 Power transistor module protector
If the temperature of the chips in the power transistor
module exceeds 105
°
C, the compressor is stopped. In
this case, the outdoor fan does not stop, and when the
temperature of the chips in the power transistor module
decreases to 105
°
C 170 seconds after operation is
stopped, another 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 reset is performed. At this time, the
3-minute delay for control of the outdoor unit will not
function; therefore, do not cancel by removing the plug
and cutting the power.
2-5 Serial signals
(1) Serial signals consist of all 96-bit signals.
(2) If the outdoor unit does not receive a serial signal, it will
stop approximately 30 seconds later. Note that this is
true only of normal operation; in test mode, it does not
stop and operation takes place based on the test mode
commands.
