Sv2 Gas Balance Control; Sv2 High Pressure Release Control; Sv2 Low Pressure Release Control; Sv41, 42 Low Pressure Release Control - Toshiba Super MMU-AP0091H Service Manual

No. Item
8 Release valve

(1) SV2 gas balance control

control

(2) SV2 high pressure release control

(3) SV2 low pressure release control

(4) SV41, 42 low pressure release control

(5) SV5 high pressure release control
9 Compressor This control is to forcedly stop the compressor in each outdoor
stop by high unit according to Pd pressure. It is individually executed by the
pressure header unit and each follower unit.
release control
(1) Contents of control
10 Case heater The case heater output includes compressor case heater and
control accumulator case heater. This control is to prevent accumulation
of refrigerant in the compressor case by turning of the power of
heater while the compressor stops, and it is executed in all the
outdoor units.
If electricity is not turned on for a specified time before the test
run after installation, a trouble of the compressor may be caused.
When the power has been interrupted for a long time and the
operation starts from the status as it was, it is desirable to turn on
the power before start of operation as per the test run time.
This control is used often together with the compressor winding
heating control. In this case, the power sound may be heard but it
is not a trouble.
(1) Contents of control
11 IPDU control IPDU controls the inverter compressor by command frequency,
frequency up/down speed, and current release control value from
the interface P .C. board.
The main controls of IPDU control P.C. board are described
below.
(1) Current release control
Operation explanation and applied data, etc.
This control is executed to balance the gas when opening
SV2 while the compressor is off, in order to decrease the
activation load in the next compressor-ON time. This control is
individually executed by the header outdoor unit and each
follower outdoor unit.
This control is to control pressure rising in low-frequency
operation of the inverter.
This control is to prevent quick pressure dropping in transient
operation. This control is individually executed by the header
outdoor unit.
This control is executed as necessary except during stop time
and thermostat-OFF time.
This control is to prevent low pressure dropping and is
individually executed by the header unit and each follower unit.
This control is executed during defrost operation, heating
start pattern control operation, and cooling operation.
This control is to prevent high pressure rising and is executed
for the header unit only.
• The compressor stops when Pd pressure is over 3.5MPa.
• Turns on during compressor-OFF
• Turns off when the detected TO sensor temp is 28°C or
higher, and turns on when it is 25°C or lower
• The operation continues for 10 minutes after compressor-
OFF changed to compressor-ON.
The output frequency is controlled by AC input current value
which is detected by inputting current sensor (CT) on the
control P.C. board to prevent the inverter input current from
rising higher than the specified value.
71
Remarks