Refrigerant Recovering (Pump Down); Unit Replacement Operation; Start And Finish Of Test Run; Replacement Operation Procedures - Mitsubishi Electric PUHZ-RP250YHA2 Service Manual

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 liquid 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 is not lit
and LED2 is lit), be sure to quickly close the gas stop valve.
In 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 3 minutes later.
If 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.
Turn off the power supply (circuit breaker.)

9-2. Unit replacement operation

When reusing the existing pipes that carried R22 refrigerant for the RP200 and RP250 models, replacement operation
must be performed before performing a test run.
If new pipes are used, these procedures are not necessary.
During replacement operation, "C5" is displayed on "A-Control Service Tool(PAC-SK52ST)".

Replacement operation procedures

Turn on the power supply.
Set DIP switch SW8-2 on the control board of the outdoor unit to ON to start replacement operation.
• The replacement operation is performed using the cooling system. Cool air will flow from the indoor unit during the replace-
ment operation.
• During the replacement operation,
control board of the outdoor unit blink together.
The duration of the replacement operation is determined by the length of the piping. Always perform the replacement
operation for longer than the stipulated time.
* Use one of he following methods to complete replacement operation. When the replacement operation ends, the unit will
automatically stop.
(1)Set SW8-2 from ON to OFF. (When ending a replacement operation of
less than 2 hours.)
• Each time SW8-2 is set from OFF to ON, the replacement operation can
be started. Always perform the replacement operation for longer than the
stipulated time.
(2) The replacement operation will automatically stop after 2 hours. (It will end with SW8-2 still in the ON position.)
• When the replacement operation has ended automatically after 2 hours of operation, there is no need to set SW8-2 from
ON to OFF; normal air conditioning operations can be started with the SW8-2 being set to ON. However, to repeat the
replacement operation, SW8-2 will have to be returned to OFF and then set to ON.

9-3. 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.
Set the operation mode (cooling/heating) using SW4-2.
Turn on SW4-1 to start test run with the operation mode set by SW4-2.
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 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 no problem with product because the check valve, itself, generates the
sound since 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.)
is displayed on the remote controller and LED1 (green) and LED2 (red) on the
TEST RUN
<Required replacement operation times>
Piping Length
0 to 20 meters
21 to 30 meters
31 to 70 meters
20
"Replacement
Operation Time"
30 minutes or more
45 minutes or more
60 minutes or more
<SW4>
ON
OFF
1 2
Stop Operation
Cooling Heating