AE-M18 (serv.man2) - Sharp Air Conditioner Service Manual (repair manual). Page 33

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Pump down is to collect the refrigerant into the outdoor unit by control of the 2 and 3-way valve and the compressor. This
method is adopted in the case of unit removal for re-installation, abandonment, repair etc. Especially, pump down must
be performed when abandoning the air conditioner. For environmental protection, do not cut the pipes connecting the
indoor and outdoor unit and release the refrigerant into air.

Pump down can be performed only under cooling operation conditions.
Perform pump down with cooling test run mode. (REFER THE FOLLOWING TEST RUN)

How to do perform the pump down:
(1) Stop the air conditioner operation and connect the gauge manifold(compound gauge) hose to the service point of 3-

way valve.

(2) Remove the air in the hose by loosening screw  a   shown in the figure below.
(3) Run the air conditioner with cooling test run mode 5 minutes.

If pump down is performed with normal cooling operation, the protection system may work and the operation may
stop.

(4) Fully close the stop valve of 2-way valve side by turming the hexagon socket screw key clockwise.
(5) Close the stop valve of 3-way valve side to half closed position.
(6) Keep running the air conditioner for 40 - 60 seconds. When the pressure of the compound gauge reads 0.05MPa,

then immediately fully close the stop valve opf 3-way side.

(7) Disconnect the hose and attach the service port cap as it was before.

If you run the air conditioner until the pressure drops below 0.05MPa, Indoor unit side become negative pressure.
As a result, moisture or dust in the air will enter into the indoor unit.
Thereforte, stop the air conditioner when 0.05MPa.

OPERATION LAMP

OPERATION PANEL

INDOOR UNIT

COMPOUND
GAUGE

OUTDOOR 
UNIT

HEXAGON SOCKET
SCREW KEY

(FULLY CLOSE)

SMALLER TUBE

STOP VALVE

LARGER TUBE

STOP VALVE

SERVICE 
PORT

(HALF CLOSED)

STOP VALVE
(2-WAY VALVE)
SMALLER TUBE
FULLY CLOSE

COMPOUND 
GAUGE

PRESSURE

GAUGE

HOSE

STOP VALVE(3-WAY VALVE)
FIRST, CLOSE UNTIL HALF-CLOSED
THEN FULLY CLOSE ACCORDING
TO GAUGE READING 0.05 - 0MPa

SERVICE PORT

TEST RUN
(1) Push the TEST RUN button on the operation panel of the

indoor unit.
The operation lamp flashes and the unit operates in the
cooling mode.

(2) Push the AUX. button to stop the TEST RUN operation.