SiUS341802E Troubleshooting by Error Code
Service Diagnosis 210
2.30 Actuation of Low Pressure Sensor
Error Code E4
Applicable
Models
All outdoor unit models
Method of Error
Detection
Make judgement 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:
îš„ Operating pressure: 0.07 MPa (10.2 psi)
Supposed
Causes
îš„ Abnormally drop in low pressure
îš„ Defective low pressure sensor
îš„ Defective outdoor unit PCB
îš„ The stop valve is not opened
Troubleshooting
Note: ∗1. Make a comparison between voltage measured by the pressure sensor and that read by the
pressure gauge.
(The pressure sensor makes measurement of voltage at its connector block to convert it to
pressure. )
Refer to page 284.
Refer to page 297.
YES
NO
NO
YES
Are the
characteristics
of the low pressure
sensor normal?
(∗1)
NO
YES
(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?
- The low pressure sensor is normal, and pressure detection with the outdoor unit main PCB is
also normal.
- The low pressure has really become low.
Replace the outdoor unit main
PCB (A1P).
Replace the low pressure sensor
(S1NPL).
Open the stop valve.
CHECK 2
CHECK 12
Check if
the low
pressure value
and the actual value
measured by
pressure sensor
are the same.
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
: Eliminate factors that cause the low pressure to decrease.
Compare the low pressure value checked with the Service Checker and the actual value
measured by pressure sensor (∗1).
Service Checker
CHECK 12
CHECK 2
CHECK 12
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