Pump Down Residual Operation - Panasonic Urban Multi MX1R Series Service Manual

Function
1.12

Pump Down Residual Operation

If refrigerant is remaining in the accumulator when the compressor starts, liquid refrigerant is sucked into
the compressor, diluting the refrigerant machine oil and reducing the lubricating performance. To prevent
this, the pump-down operation discharges refrigerant from the low pressure side when the unit is not in
operation.
Residual operation may be carried out for Max.10 minutes under the following conditions.
1.
2. When the thermostat is ON during residual operation, residual operation is not carried out if the total of
Thermostat
Compressor and
outdoor unit fan
∗ When outdoor temperature (R1T) is less than -5°C and a stop command is reseived from the
Outdoor Unit
Function
„ During defrost or oil return, residual operation is not carried out even if a stop command comes.
Notes:
„ Forced thermostat OFF occurs if defrost or oil return signal comes during residual operation.
254
Secondary side heat exchanger 4 way valve (Y2R) is ON.
Discharge pipe thermistor (R3-1T) on inverter side: 95°C or lower
Outside air temperature thermistor (R1T) < 0°C
&
When compressor continuous operating time is less than 10 minutes and thermostat is OFF, or
when stop command is received from remote controller
OR
Within 20 minutes after defrost or oil return operation
R5T (oil temperature) ≤ Te+15
Max. 10 min.
ON
Thermostat
OFF
ON
Compressor and
outdoor unit fan
OFF
1+2+3 is 10 minutes or more.
Max. 10 min.
ON
OFF
1
ON
OFF
thermostat sensor, etc., residual operation is carried out for 10 minutes without fail. (Operation may
however stop for discharge pipe or high/low pressure safety.)
Outdoor air (R1T)
R1T < -10°C 86Hz
-10°C ≤ R1T < 0°C
76Hz
R1T ≥ 0°C
62Hz
Residual operation for 10 min.
Residual
operation
2
Residual operation not carried out
if 1 + 2 + 3 is 10 minutes or more.
Compressor Electronic
expansion valve
INV STD
OFF 0~300 pulses
OFF 0~300 pulses
OFF 0~300 pulses
Function Urban Multi "MX1R, ME1R Series" Using R-407C
Operation may stop during the 10 minutes
residual operation due to protection discharge,
high/low pressure, etc.
Max. 10 min.
3
Thermostat
ON
Pressure equalizing
Solenoid valve
ON or OFF
ON or OFF
ON or OFF
PACD011001C2
(VL006)
(VL007)
Time
10 min.
10 min.
10 min.