Mitsubishi Electric PFD-P250VM-E, Service Handbook, Page: 211 / 326

[8-5 Pressure Sensor Circuit Configuration and Troubleshooting Pressure Sensor Problems ]
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8-5 Pressure Sensor Circuit Configuration and Troubleshooting
Pressure Sensor Problems
8-5-1 Comparing the High-Pressure Sensor Measurement and Gauge Pressure
By configuring the digital display setting switch (SW4 (when SW6-10 is set to OFF)) as shown in the figure below, the pressure
as measured by the high-pressure sensor appears on the LED1 on the control board.
(1) While the sensor is stopped, compare the gauge pressure and the pressure displayed on self-
diagnosis LED1.
1) When the gauge pressure is between 0 and 0.098MPa [14psi], internal pressure is caused due to gas leak.
2) When the pressure displayed on self-diagnosis LED1 is between 0 and 0.098MPa [14psi], the connector may be defective or
be disconnected. Check the connector and go to (4).
3) When the pressure displayed on self-diagnosis LED1 exceeds 4.15MPa [601psi], go to (3).
4) If other than 1), 2) or 3), compare the pressures while the sensor is running. Go to (2).
(2) Compare the gauge pressure and the pressure displayed on self-diagnosis LED1 while the sen-
sor is running. (Compare them by MPa [psi] unit.)
1) When the difference between both pressures is within 0.098MPa [14psi], both the high pressure sensor and the control board
are normal.
2) When the difference between both pressures exceeds 0.098MPa [14psi], the high pressure sensor has a problem. (perfor-
mance deterioration)
3) When the pressure displayed on self-diagnosis LED1 does not change, the high pressure sensor has a problem.
(3) Remove the high pressure sensor from the control board to check the pressure on the self-di-
agnosis LED1.
1) When the pressure displayed on self-diagnosis LED1 is between 0 and 0.098MPa [14psi], the high pressure sensor has a
problem.
2) When the pressure displayed on self-diagnosis LED1 is approximately 4.15MPa [601psi], the control board has a problem.
(4) Remove the high pressure sensor from the control board, and short-circuit between the No.2
and 3 connectors (63HS1) to check the pressure with self-diagnosis LED1.
1) When the pressure displayed on the self-diagnosis LED1 exceeds 4.15MPa [601psi], the high pressure sensor has a problem.
2) If other than 1), the control board has a problem.
SW4
ON
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
The figure at left shows that the switches 1 through 5 are set to ON and 6 through 10 are set to OFF.
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