Troubleshooting With Gauge Pressure - Komatsu PC88MR-10 Shop Manual

80 Appendix

Troubleshooting with gauge pressure

Troubleshooting with gauge pressure

Perform troubleshooting according to the high and low gauge pressures of the cooling cycle. For details, see
"Connection of service tool".
a The gauge pressure varies largely with the weather condition and operating condition of the machine.
Check the gauge pressure under the pressure measurement conditions.
Pressure of high-pressure line is too high: Min. approx. 2.5 MPa {25 kg/cm
Pressure of high-pressure line is too low: Max. approx. 1 MPa {10 kg/cm
Pressure of low-pressure line is too high: Min. approx. 0.3 MPa {3 kg/cm
Pressure of low-pressure line is too low: Max. approx. 0.05 MPa {0.5 kg/cm
a Dual pressure switch turns "OFF" to protect the air conditioner circuit if the pressure of the high-pressure
or low-pressure line is abnormal.
[Measurement condition for pressure]
Ambient temperature
Engine speed
Air conditioner switch
Fan switch
Set temperature
Dual pressure switch
a The switch is normally "ON", and becomes "OFF" when it detects abnormal pressure for compressor
operation.
LA: 0.20 MPa {2 kg/cm 2
LB: 0.02 MPa {0.2 kg/cm
HA: 3.14 MPa {32 kg/cm
HB: 0.59 MPa {6 kg/cm 2
80-76
Item
}
2 }
2 }
}
(PC220-3840-362-A-00-A)
2 }
2 }
2 }
2
Condition value
25 to 50 °C
1,500 rpm
ON
HI
Cool-Max
}
PC88MR-10