Mitsubishi Electric PUHZ-RP35VHA4 Service Manual page 33

9-1. Refrigerant recovering (pump down)
Perform the following procedures to recover the refrigerant when moving the indoor unit or the outdoor unit.
Turn on the power supply (circuit breaker).
When power is supplied, make sure that "CENTRALLY CONTROLLED" is not displayed on the remote controller. If
"CENTRALLY CONTROLLED" is displayed, the refrigerant recovering (pump down) cannot be completed normally.
After the gas stop valve is closed, set the SWP switch on the control board of the outdoor unit to ON. The compressor (outdoor
unit) and fans (indoor and outdoor units) start operating and refrigerant recovering operation begins. LED1 and LED2 on the
control board of the outdoor unit are lit.
Set the SWP switch (push-button type) to ON in order to perform refrigerant recovering operation only when the unit is
stopped. However, refrigerant recovering operation cannot be performed until compressor stops even if the unit is stopped.
Wait 3 minutes until compressor stops and set the SWP switch to ON again.
Because the unit automatically stops in about 2 to 3 minutes after the refrigerant recovering operation (LED1 and LED2 are
lit), be sure to quickly close the gas stop valve.
In case the outdoor unit is stopped when LED1 and LED2 are lit, open the liquid stop valve completely, and then repeat step
2 3 minutes later.
If the refrigerant recovering operation has been completed normally (LED1 and LED2 are lit), the unit will remain stopped
until the power supply is turned off.
Turn off the power supply (circuit breaker.)
* Note that when the length of the extension piping is long, it may not be possible to perform a pump-down operation. When
performing the pump-down operation, make sure that the low pressure is lowered to near 0 MPa (gauge).
9-2. 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/heating) can be set up.
1Set the operation mode (cooling/heating) using SW4-2.
2Turn on SW4-1 to start test run with the operation mode set by SW4-2.
3Turn 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.
Note:
The operation mode cannot be changed by SW4-2 during test run. (To change test run mode, stop the unit by SW4-1,
change the operation mode and restart the test run by SW4-1.)
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<SW4>
ON
OFF
1 2
Stop Operation
Cooling Heating