Output Of Pcb - Panasonic U-120ME2U9 Service Manual

4. Special Control

4. Output of PCB

Items
Solenoid valve
Expansion valve
1
Crankcase heater
(1) 4-way Valve [20S]
2
This valve turns OFF at cooling mode, and turns ON at heating mode.
This valve turns OFF at defrosting control.
* When the outdoor unit stops, the 4-way valve maintains in the same state as before.
3
(2) SAVE Valve [SAVE]
This valve turns ON for 5 seconds before the inverter compressor starts. After the inverter compressor starts, the
● This valve turns ON for 5 seconds before the inverter compressor starts.
valve is ON for 10 seconds. After that, it turns OFF.
After the inverter compressor starts, the valve turns ON for 10 seconds. Then it turns OFF.
● This valve turns ON for 30 seconds after the outdoor unit stops. Then it turns OFF.
● This valve turns ON when high pressure sensor detects 496psi (3.42MPa) to prevent abnormal pressure.
4
This valve turns OFF when the high pressure goes down below 481.5psi (3.32MPa).
● This valve might turn ON when the system capacity is excessive although the inverter compressor operates at
Min. frequency.
● This valve turns ON in the following status :
(Compressor discharge temperature - High pressure saturation temperature) < 9deg F (5deg C)
● Under control of 4-way valve adjustment control
5
● This valve turns ON when low pressure sensor goes down 24.7psi (0.17MPa) to prevent abnormal pressure.
This valve turns OFF when low pressure sensor increase 29psi (0.20MPa) or over.
6
This valve turns ON for 30 seconds after the outdoor unit stops. After that, it turns OFF.
This valve turns ON when the high pressure sensor detects α to prevent
abnormal pressure shown in the table at right.
This valve turns OFF when the high pressure goes down below β shown
in the table at right.
7
This valve turns ON when the high pressure switch is activated.
This valve stays ON for 10 seconds after the high pressure switch returns in normal.
After that, it turns OFF.
This valve might turn ON when the system capacity is excessive although the inverter compressor operates at
minimum frequency.
8
This valve turns ON while the discharge temperature of the compressor is low.
This valve turns ON during the operation of 4-way valve control.
9
4-way valve
Save valve
Refrigerant control valve
Refrigerant balance valve
Oil recovery valve
By-pass valve
Accumulator valve
O valve
2
MOV for heat exchanger 1
MOV for heat exchanger 2
SC circuit expansion valve
Crankcase heater for 1st compressor
Crankcase heater for 2nd compressor
5 seconds
SAVE valve
Compressor
Inverter compressor starts
Valve turns ON
Remarks
10 seconds
Valve turns OFF
1 - 12
2WAY VRF SYSTEM
2WAY VRF SYSTEM
Control Functions
Control Functions
Indication on PCB
20S
SAVE
RCV
RBV
ORVR
BPV
ACV
O
2
MOV1
MOV2
MOV4
CH1
CH2
α 496.0 psi (3.42 MPa)
β 481.5 psi (3.32 MPa)