Mitsubishi Electric Mr.Slim PUZ-SM100VKA Service Manual page 26

8-1. REFRIGERANT COLLECTING (PUMP DOWN)
When relocating or disposing of the indoor/outdoor unit, pump down the system following the procedure below so that no refriger-
ant is released into the atmosphere.
1 Turn off the power supply (circuit breaker).
2 Connect the low pressure valve on the gauge manifold to the charge plug (low pressure side) on the outdoor unit.
3 Close the liquid stop valve completely.
4 Supply power (circuit breaker).
● When power is supplied, make sure that "CENTRALLY CONTROLLED" is not displayed on the remote controller. If "CEN-
TRALLY CONTROLLED" is displayed, the refrigerant collecting (pump down) cannot be completed normally.
● Startup of the indoor-outdoor communication takes about 3 minutes after the power (circuit breaker) is turned on. Start the
pump-down operation 3 to 4 minutes after the power (circuit breaker) is turned on.
5 Perform the refrigerant collecting operation (cooling test run).
● Push the pump-down SWP switch (push-button type) on the control board of the outdoor unit. The compressor and ventila-
tors (indoor and outdoor units) start operating (refrigerant collecting operation begins). (LED1 and LED2 on the control board
of the outdoor unit are lit.)
● Only push the pump-down SWP switch if the unit is stopped. However, even if the unit is stopped and the pump-down SWP
switch is pushed less than 3 minutes after the compressor stops, the refrigerant collecting operation cannot be performed.
Wait until the compressor has been stopped for 3 minutes and then push the pump-down SWP switch again.
6 Fully close the stop valve on the gas pipe side of the outdoor unit when the pressure gauge on the gauge manifold shows 0.05
to 0 MPa [Gauge] (approx. 0.5 to 0 kgf/cm²) and quickly stop the air conditioner.
● Because the unit automatically stops in about 3 minutes when the refrigerant collecting operation is completed (LED1 off,
LED2 lit), be sure to quickly close the gas stop valve. However, if LED1 is lit, LED2 is off, and the unit is stopped, open the
liquid stop valve completely, close the valve completely after 3 minutes or more have passed, and then repeat step 5. (Open
the gas stop valve completely.)
● If the refrigerant collecting operation has been completed normally (LED1 off, LED2 lit), the unit will remain stopped until the
power supply is turned off.
● Note that when the extension piping is very long with a large refrigerant amount, it may not be possible to perform a pump-
down operation. In this case, use refrigerant recovery equipment to collect all of the refrigerant in the system.
7 Turn off the power supply (circuit breaker), remove the gauge manifold, and then disconnect the refrigerant pipes.
Warning:
When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes.
• If the refrigerant pipes are disconnected while the compressor is operating and the stop valve is open, the pressure in
the refrigeration cycle could become extremely high if air is drawn in, causing the pipes to burst, personal injury, etc.
8-2. START AND FINISH OF TEST RUN
• Operation from the indoor unit
Execute the test run using the installation manual for the indoor unit.
• Operation from the outdoor unit
By using the DIP switch SW4 on the control board of outdoor unit, test run can be started and finished, and its operation
mode (cooling) can be set up.
1 Turn on SW4-1 to start test run.
2 Turn off SW4-1 to finish the test run.
• There may be a faint knocking sound around the machine room after power is supplied, but this is no problem with product
because the linear expansion pipe is just moving to adjust opening pulse.
• There may be a knocking sound around the machine room for several seconds after compressor starts operating, but this
is no problem with product because the check valve itself, generates the sound because pressure difference is small in the
refrigerant circuit.
OCH708
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