Daikin REYQ-AATJA, Service Manual

Page: 353 / 495

SiUS372201EA Troubleshooting by Error Code
Part 6 Service Diagnosis 346
Reference
Reference
3.36 Activation of Low Pressure Sensor
Applicable
Models
All outdoor unit models
Error Code
E4
Method of Error
Detection
Make judgment of pressure detected by the low pressure sensor with the outdoor unit main PCB.
Error Decision
Conditions
When low pressure caused a drop while the compressor is in operation:

Operating pressure: 0.07 MPa (10.2 psi)
Supposed
Causes
 Abnormal drop in low pressure

Defective low pressure sensor
 Defective outdoor unit main PCB
 The stop valve is not opened
Troubleshooting
CHECK 2 Refer to page 425.
CHECK 12 Refer to page 437.
YES
NO
(1) Mount a pressure gauge on the low pressure service port.
(2) Reset the operation using the remote controller, and then restart the operation.
Is the stop valve open?
Open the stop valve.
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Replace the outdoor unit
main PCB (A1P).
NO
YES
Are both
pressure values the
same?
-The low pressure sensor is normal, and outdoor unit main PCB is also
normal.
-The low pressure has really become low.
CHECK 2
: Eliminate factors that cause the low pressure to fall.
Connect the service checker, and then compare the low pressure value
measured by the service checker with the voltage measurement of the
connector of the pressure sensor (
1)
Service Checker
CHECK 12
Replace the low pressure sensor
(S1NPL).
NO
Compare the voltage
measurement of the connector of the
pressure sensor ( 1) with the measurement
of the pressure gauge. Are the
characteristics of the low
pressure sensor
normal?
CHECK 12
YES
( 1) Use the table on CHECK 12 to
convert the voltage measurement into
pressure measurement.