Special Functions; Refrigerant Collecting (Pump Down) - Mitsubishi Electric PUZ-A12 NHA7 Manuel D'installation

7. Test run
► The followings must be checked as well.
• The outdoor unit is not faulty. LED1 and LED2 on the control board of the outdoor
unit fl ash when the outdoor unit is faulty.
• Both the gas and liquid stop valves are completely open.
• A protective sheet covers the surface of the DIP switch panel on the control board
of the outdoor unit. Remove the protective sheet to operate the DIP switches easily.
7.2. Test run
7.2.1. Using SW4 in outdoor unit
1) PUZ Type
SW4-1 ON
Cooling operation
SW4-2 OFF
SW4-1 ON
Heating operation
SW4-2 ON
2) PUY Type
SW4-1 ON
Cooling operation
SW4-2 ON or OFF
* After performing the test run, set SW4-1 to OFF.
• After power is supplied, a small clicking noise may be heard from the inside of the
outdoor unit. The electronic expansion valve is opening and closing. The unit is
not faulty.

8. Special functions

A
X
X
SW1
A Circuit diagram example (low noise mode)
B On-site arrangement
C External input adapter (PAC-SC36NA-E)
X: Relay
A
X Y
X
SW2
SW3
Y
A Circuit diagram example
(Demand function)
B On-site arrangement
X, Y: Relay

8.3. Refrigerant collecting (pump down)

Perform the following procedures to collect the refrigerant when moving the indoor
unit or the outdoor unit.
1 Supply power (circuit breaker).
• When power is supplied, make sure that "CENTRALLY CONTROLLED" is not
displayed on the remote controller. If "CENTRALLY CONTROLLED" is dis-
played, the refrigerant collecting (pump down) cannot be completed normally.
• Start-up 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 min-
utes after the power (circuit breaker) is turned ON.
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 fans (indoor and outdoor
units) start operating and refrigerant collecting operation begins. LED1 and LED2
on the control board of the outdoor unit are lit.
• Only set the SWP switch (push-button type) to ON if the unit is stopped. How-
ever, even if the unit is stopped and the SWP switch is set to ON less than 3
minutes after the compressor stops, the refrigerant collecting operation cannot
be performed. Wait until compressor has been stopped for 3 minutes and then
set the SWP switch to ON again.
10
C D
CNDM
Orange
1
Brown
Fig. 8-1
Red
3
D Outdoor unit control board
E Max. 10 m, 33 ft
F Power supply for relay
C D
CNDM
Orange
1
Brown
Fig. 8-2
Red
3
C External input adapter
(PAC-SC36NA-E)
D Outdoor unit control board
E Max. 10 m, 33 ft
F Power supply for relay
• Make sure that the all of the SW5 DIP switches for function changes on the control
board of the outdoor unit are set to OFF. If all of the SW5 switches are not set to
OFF, record the settings and then set all of the switches to OFF. Begin recovering
the refrigerant. After moving the unit to a new location and completing the test run,
set the SW5 switches to the previously recorded settings.
• A few seconds after the compressor starts, a clanging noise may be heard from
the inside of the outdoor unit. The noise is coming from the check valve due to the
small difference in pressure in the pipes. The unit is not faulty.
The test run operation mode cannot be changed by DIP switch SW4-2 during
the test run. (To change the test run operation mode during the test run, stop
the test run by DIP switch SW4-1. After changing the test run operation mode,
resume the test run by switch SW4-1.)
7.2.2. Using remote controller
Refer to the indoor unit installation manual.
8.1. Low noise mode (on-site modifi cation) (Fig. 8-1)
By performing the following modifi cation, operation noise of the outdoor unit can be
reduced by about 3-4 dB.
The low noise mode will be activated when a commercially available timer or the
contact input of an ON/OFF switch is added to the CNDM connector (option) on the
control board of the outdoor unit.
• The ability varies according to the outdoor temperature and conditions, etc.
1 Complete the circuit as shown when using the external input adapter
(PAC-SC36NA-E). (Option)
2 SW7-1 (Outdoor unit control board): OFF
3 SW1 ON: Low noise mode
SW1 OFF: Normal operation
8.2. Demand function (on-site modifi cation) (Fig. 8-2)
By performing the following modifi cation, energy consumption can be reduced to
0–100% of the normal consumption.
The demand function will be activated when a commercially available timer or the
contact input of an ON/OFF switch is added to the CNDM connector (option) on the
control board of the outdoor unit.
1 Complete the circuit as shown when using the external input adapter
(PAC-SC36NA-E). (Option)
2 By setting SW7-1 on the control board of the outdoor unit, the energy consump-
tion (compared to the normal consumption) can be limited as shown below.
SW7-1 SW2
OFF
ON
Demand
ON
function
ON
OFF
3 Because the unit automatically stops in about 2 to 3 minutes when the refrigerant
collecting operation is completed (LED1 off, LED2 lit), be sure to quickly close
the gas stop valve. If LED1 is lit and LED 2 is off and the outdoor unit is stopped,
refrigerant collection is not properly performed. Open the liquid stop valve com-
pletely, and then repeat step 2 after 3 minutes have passed.
• 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.
4 Turn off the power supply (circuit breaker).
• Note that when the extension piping is very long with large refrigerant amount,
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).
Warning:
When pumping down the refrigerant, stop the compressor before disconnect-
ing the refrigerant pipes. The compressor may burst if air etc. get into it.
SW3 Energy consumption
OFF 100%
OFF 75%
ON 50%
ON 0% (Stop)