Panasonic Urban Multi MX1R Series Service Manual page 464

PACD011001C2
3.1.17 Heating Pump-Down Residual Operation
Conduct an operation during stop mode to discharge refrigerant from the low pressure side, since liquid
refrigerant remaining in the accumulator can be sucked into the compressor during startup and dilutes the
refrigerating machine oil in the compressor and lowers the lubricating performance.
[Residual operation starting condition]
DSHi : INV discharge pipe superheat degree
Th6-Te : Suction pipe temp. -Low pressure equivalent saturation temp.
[Description of movement]
Movement
∗ Receiver gas relief solenoid valve is open and liquid refrigerant is moved to liquid line for 60 seconds
[Ending condition]
3.1.18 Backup Operation
[Purpose]
The following backup operation is activated when the constant-speed compressor protection device
operates.
< For 2-compressor system >
„ When the STD compressor OC operates, the operation continues using only the inverter compressor
< For 3-compressor system >
„ When the STD compressor OC operates, the operation continues using compressor except last started
„ When OC operates again immediately after a backup operation (within 5 minutes after STD compressor
„ If OC activates again, only the inverter compressor is used for the operation.
„ The compressor in which OC is activated is prohibited to operate until power reset is conducted for a
Function UM Combination "MA1R Series" Using R-407C
Thermostat ON → OFF
& DSHi < 20°C
OR
Th6 – Te < 10°C
Compressor
67Hz+OFF
PI control when SHS = 10°C
after entering pump-down residual operation.
However, this relief solenoid valve closes at Th6-Te < 0.
DSHi > 90°C
Th6 – Te < 10°C
& LP < 0.07MPa
Tc > 48.6°C
10 min elapse
based on all remote control reset. (for 3 hours only)
STD compressor based on remote control reset. (for 3 hours only)
startup), STD1 and STD2 are switched and operation is retried.
(In any case, the backup operation ends after 3 hours.)
restart.
Outdoor unit
Motorized valve Solenoid valve for hot gas
Initial 2000 pls →
Outline of Control
Indoor unit
Motorized valve
ON (equalization) 500 pls (all indoor unit)
443