Pressure Sensor Failure - Panasonic U-10MF1E8 Service Manual

16. Pressure Sensor Failure

This system contains 2 types of pressure sensors: a high-pressure sensor and a low-pressure sensor.
(1) High-pressure sensor failure
Identification of a failure caused by a loose or displaced connector is based on the relationship between the pres-
sure detected by the high-pressure sensor and the operation of the high-pressure switch, and on the relationship
between the temperature detected by the high-pressure sensor and the various temperature thermistors.
However, when the pressure increases suddenly, the judgment for the high-pressure sensor failure alarm may
1
occur before operation of the high-pressure switch. Therefore, before concluding that there is a failure in the
pressure sensor, first verify that the service valve was not accidentally left closed, that there are no blocked cir-
cuits, and that there is no leakage of refrigerant into stopped outdoor units. Also check for a difference between
the high pressure measured by the manifold gauge and the pressure detected by the pressure sensor.
(2) Low-pressure sensor failure
Identification of a failure caused by a loose or displaced connector is based on the relationship between the
temperature detected by the low-pressure sensor and the various temperature thermistors.
Before concluding that a failure has occurred, check for a difference between the low pressure measured by the
manifold gauge and the pressure detected by the low-pressure sensor.
Alarm display
High-pressure sensor failure
F16
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Control Functions
Low-pressure sensor failure
F17
3-WAY SYSTEM