Pump Down; Preparation For Pump Down; Pump Down Procedure - Fujitsu LHT Series Installation Manual

13. PUMP DOWN

Never touch electrical components such as the terminal blocks except the button on
the display board. It may cause a serious accident such as electric shock.
During the pump-down operation, make sure that the compressor is turned off before
you remove the refrigerant piping.
Do not remove the connection pipe while the compressor is in operation with 2-way or
3-way valve open. This may cause abnormal pressure in the refrigeration cycle that
leads to breakage and even injury.
Perform the pump down operation before disconnecting any refrigerant pipe or electric
cable.
Collect refrigerant from the service port or the 3-way valve if pump down cannot be
performed.
In case of a group control system installation, do not turn the power off until pump down
is completed in all outdoor units.
(Group control system installation described in "SPECIAL INSTALLATION METHODS"
in the installation manual of the indoor unit.)
• Operate [PUMP DOWN] button on the display board in the manner described
below.
LED display part
/
SW107 SW108 SW109 SW112 SW110

13.1. Preparation for pump down

• Confi rm that the power is off , and then open the service panel.

13.2. Pump down procedure

(1) Check the 3-way valves (both the liquid side and gas side) are opened.
(2) Turn the power on.
PUMP
POWER/
ERROR
DOWN
MODE
(L1)
● ○ ○
○ ●
Sign " ": Lights off, " ": Lights on
(3) Press [PUMP DOWN] button for 3 seconds or more after 3 minutes after power on.
PUMP
POWER/
ERROR
DOWN
MODE
(L1)
● ○ ●
○ ●
Sign " ": Lights off, " ": Lights on
LED display lights on as shown in the above fi gure, and the fans and the
compressor start operating.
• If the [PUMP DOWN] button is pressed while the compressor is operating, the
compressor will stop, then start again in about 3 minutes.
(4) LED display will change as shown below about 3 minutes after the compressor
starts. Fully close the 3-way valve on the liquid pipe side at this stage.
PUMP
POWER/
ERROR
DOWN
MODE
(L1)
● ○ ●
○ ●
Sign " ": Lights off, " ": Lights on
• If the valve on the liquid pipe side is not closed, the pump down cannot be performed.
En-17
WARNING
CAUTION
Button part
LOW PEAK
NOISE CUT
(L2) (L3) (L4) (L5)
○ ○ ○ ○
LOW PEAK
NOISE CUT
(L2) (L3) (L4) (L5)
○ ○ ● ●
LOW PEAK
NOISE CUT
(L2) (L3) (L4) (L5)
○ ○ ○ ●
(5) When LED display changes as shown in the below fi gure, close the 3-way valve on
the gas pipe side tightly.
POWER/
ERROR
MODE
● ○
○
Sign " ": Lights off, "
• If the valve on the gas pipe side is not closed, refrigerant may fl ow into the piping
after the compressor stops.
Hexagon wrench
(6) LED display changes after 1 minute as shown in the fi gure below.
POWER/
ERROR
MODE
● ○
○
Sign " ": Lights off, "
Fans and compressor stop automatically.
• If the pump down is successfully completed (the above LED display is shown), the
outdoor unit remains stopped until the power is turned off .
(7) Turn the power off .
POWER/
ERROR
MODE
○ ○
○
Sign " ": Lights off
Pump down is completed.
NOTES:
• To stop pump down, press the [PUMP DOWN] button again.
• To start the pump down again after the compressor is automatically stopped due to
an error, disconnect the power supply and open the 3-way valves. Wait 3 minutes,
reconnect the power supply and start the pump down again.
• When starting the operation after completion of the pump down, disconnect the power
supply, and then open the 3-way valves. Wait 3 minutes, reconnect the power supply
and perform a test run in the Cooling operation mode.
• If an error occurs, recover the refrigerant from service port.
(L6)
○
(L6)
●
(L6)
●
PUMP LOW
DOWN NOISE
(L1) (L2) (L3) (L4)
● ○ ○ ○
●
": Lights on
Step (4) Step (5)
Closing direction Closing direction
Liquid pipe
Gas pipe
PUMP
LOW NOISE
DOWN
(L1) (L2) (L3) (L4)
● ○ ○ ○
●
": Lights on
PUMP
LOW NOISE
DOWN
(L1) (L2) (L3) (L4)
○ ○ ○ ○
PEAK
CUT
(L5) (L6)
○ ●
PEAK
CUT
(L5) (L6)
○ ○
PEAK
CUT
(L5) (L6)
○ ○