Refrigerant System Diagram - Mitsubishi Electric Mr.SLIM PUZ-HA24NHA Service Manual

9

REFRIGERANT SYSTEM DIAGRAM

PUZ-HA24NHA
Ball valve
Refrigerant
GAS pipe
connection
[15.88(5/8)
Linear
expansion valve-B
Refrigerant
LIQUID pipe
connection
[9.52
(3/8)
Stop valve
(with service port)
REFRIGERANT COLLECTING (PUMP DOWN)
When relocating or disposing of the indoor/outdoor unit, pump down the system following the procedures below so that no refrig-
erant is released into the atmosphere.
1 Turn off the power supply (circuit breaker).
2 Connect the low pressure valve on the gauge manifold to the charge plug (low pressure side) on the outdoor unit.
3 Close the liquid stop valve completely.
4 Supply power (circuit breaker).
• When power is supplied, make sure that "CENTRALLY CONTROLLED" is not displayed on the remote controller. If "CEN-
TRALLY CONTROLLED" is displayed, the refrigerant collecting (pump down) cannot be completed normally.
• Startup 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 minutes after the power (circuit breaker) is turned on.
5 Perform the refrigerant collecting operation (cooling test run).
• Push the pump-down SWP switch (push-button type) on the control board of the outdoor unit. The compressor and ventilators
(indoor and outdoor units) start operating (refrigerant collecting operation begins). (LED1 and LED2 on the control board of
the outdoor unit are lit.)
• Only push the pump-down SWP switch if the unit is stopped. However, even if the unit is stopped and the pump-down SWP
switch is pushed less than 3 minutes after the compressor stops, the refrigerant collecting operation cannot be performed.
Wait until the compressor has been stopped for 3 minutes and then push the pump-down SWP switch again.
6 Fully close the ball valve on the gas pipe side of the outdoor unit when the pressure gauge on the gauge manifold shows 0.05
to 0 MPa [Gauge] (approx. 0.5 to 0 kgf/cm²) and quickly stop the air conditioner.
• Because the unit stops automatically in about 3 minutes when the refrigerant collecting operation is completed (LED1 off,
LED2 lit), be sure to quickly close the gas ball valve. However, if LED1 is lit, LED2 is off, and the unit is stopped, open the
liquid stop valve completely, close the valve completely after 3 minutes or more have passed, and then repeat step 5. (Open
the gas ball valve completely.)
• 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.
• Note that when the extension piping is very long with a large refrigerant amount, it may not be possible to perform a pump-
down operation. In this case, use refrigerant recovery equipment to collect all of the refrigerant in the system.
7 Turn off the power supply (circuit breaker), remove the gauge manifold, and then disconnect the refrigerant pipes.
Warning:
When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes.
• If the refrigerant pipes are disconnected while the compressor is operating and the stop valve (ball valve) is open, the pressure
in the refrigeration cycle could become extremely high if air is drawn in, causing the pipes to burst, personal injury, etc.
OCH721A
Solenoid valve
(4-way valve)
Strainer
(#50)
Charge plug
(Low pressure)
Strainer
(#100)
Strainer
(#100)
Power
receiver
Strainer
(#100)
Heat exchanger
Charge plug
(High pressure)
Muffler
High pressure
switch 63H
Thermistor TH4
(Discharge)
Thermistor TH33
(Comp. surface)
Linear expansion valve-A
Compressor
16
Unit: mm (in)
Thermistor TH7
(Ambient)
Thermistor
TH6
(2-phase pipe)
Thermistor TH3
(Liquid)
Distributor
Strainer
(#100)
Thermistor TH8
(Heat sink)
Power circuit board
Refrigerant flow in cooling
Refrigerant flow in heating