Mitsubishi Electric MXZ-4C36NAHZ Technical & Service Manual page 115

<HIGH PRESSURE SENSOR>
Comparing the High Pressure Sensor Measurement and Gauge Pressure
By configuring the digital display setting switch (SW1) as shown in the figure below, the pressure as measured by the high pressure
sensor appears on the LED1, 2 on the control board.
ON
The figure at left shows that the switches 1 through 4 are set to ON and 5 through 8 are set to OFF.
1 2 3 4 5 6 7 8
(1) While the outdoor unit is stopped, compare the gauge pressure and the pressure displayed on self-diagnosis LED1, 2.
1) When the gauge pressure is between 0 and 14 PSIG [0.098 MPaG], internal pressure is caused due to gas leak.
2) When the pressure displayed on self-diagnosis LED1, 2 is between 14 PSIG [0.098 MPaG], the connector may be defective or
be disconnected. Check the connector and go to (4).
3) When the pressure displayed on self-diagnosis LED1, 2 exceeds 725 PSIG [5.0 MPaG], 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 LED1,2 after 15 minutes have passed since
the start of operation. (Compare them by PSIG [MPaG] unit.)
1) When the difference between both pressures is within 36 PSIG [0.25 MPaG], both the high pressure sensor and the control board
are normal.
2) When the difference between both pressures exceeds 36 PSIG [0.25 MPaG], the high pressure sensor has a problem. (perfor-
mance deterioration)
3) When the pressure displayed on self-diagnosis LED1, 2 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-diagnosis LED1, 2.
1) When the pressure displayed on self-diagnosis LED1, 2 is between 0 and 14 PSIG [0.098 MPaG], the high pressure sensor has a
problem.
2) When the pressure displayed on self-diagnosis LED1, 2 is approximately 725 PSIG [5.0 MPaG], the control board has a problem.
(4) Remove the high pressure sensor from the control board, and short-circuit between the pin 2 and pin 3 connectors
(63HS) to check the pressure with self-diagnosis LED1, 2.
1) When the pressure displayed on the self-diagnosis LED1, 2 exceeds 725 PSIG [5.0 MPaG], the high pressure sensor has a problem.
2) If other than 1), the control board has a problem.
High Pressure Sensor Configuration (63HS)
The high pressure sensor consists of the circuit shown in the figure below. If 5 V DC is applied between the white and the black
wires, voltage corresponding to the pressure between the blue and the black wires will be output, and the value of this voltage
will be converted by the microcomputer. The output voltage is 0.078 V per 14 PSIG [0.098 MPaG].
Note:
The pressure sensor on the body side is designed to connect to the connector. The connector pin number on the body side
is different from that on the control board side.
Body side
Vcc Pin 1
Vout Pin 2
GND Pin 3
OUTDOOR MULTI CONTROLLER
CIRCUIT BOARD
5 V DC
3
WH
2
BU
Vout
1
BK
63HS
3–1: 5 V (DC)
2–1: Output Vout (DC)
OCH573E
SW1
ON
1 2 3 4 5 6
Control board side
Pin 3
Pin 2
Pin 1
Pressure: 0–725 PSIG [5.0 MPaG]
Vout: 0.5–4.5 V
0.078 V/14 PSIG [0.098 MPaG]
MICRO
PROCESSOR
GND
7 8
Vout (V)
4.5
2.5
0.5
0
PRESSURE
363 725
(PSIG)
(MPaG)
2.5 5