Refrigerant Recovering; Start And Finish Of Test Run - Mitsubishi Electric PUZ-A18NHA4 Service Manual

1. Refrigerant recovering (pump down)
Perform the following procedures to recover the refrigerant when moving the indoor unit or the outdoor unit.
1 Turn on the power supply (circuit breaker).
wWhen power is supplied, make sure that "CENTRALLY CONTROLLED" is not displayed on the remote controller. If
"CENTRALLY CONTROLLED" is displayed, the refrigerant collecting (pump down) cannot be completed normally.
2 After the liquid stop valve is closed, set the SWP switch on the control board of the outdoor unit to ON. The compressor
(outdoor unit) and ventilators (indoor and outdoor units) start operating and refrigerant recovering operation begins. LED1
and LED2 on the control board of the outdoor unit are lit.
wSet 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.
3 Because the unit automatically stops in about 2 to 3 minutes after the refrigerant recovering operation (LED1 is not lit and
LED2 is lit), be sure to quickly close the gas stop valve.
wIn case the outdoor unit is stopped when LED1 is lit and LED2 is not lit, open the liquid stop valve completely, and then
repeat step 2 3 minutes later.
wIf the refrigerant recovering operation has been completed normally (LED1 is not lit and LED2 is lit), the unit will remain
stopped until the power supply is turned off.
4 Turn off the power supply (circuit breaker.)

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.
1 Set the operation mode (cooling/heating) using SW4-2.
2 Turn on SW4-1 to start test run with the operation mode set by SW4-2.
3 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
not a problem with the product because the linear expansion valve 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 not a 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.)
27
<SW4>
ON
OFF
1 2
Stop operation
Cooling Heating
(PUZ only)