Service manual

Troubleshooting by Indication on the Remote Controller SiUS28-902_a
129 Troubleshooting
3.35 “U0” Outdoor Unit: Low Pressure Drop Due to
Refrigerant Shortage or Electronic Expansion Valve
Failure
Remote
Controller
Display
U0
Applicable
Models
RZQ18~30PVJU
Method of
Malfunction
Detection
Short of gas malfunction is detected by discharge pipe temperature thermistor and low pressure
saturation temperature.
Malfunction
Decision
Conditions
Microcomputer judge and detect if the system is short of refrigerant.
Malfunction is not decided while the unit operation is continued.
Supposed
Causes
 Out of gas or refrigerant system clogging (incorrect piping)
 Defect of pressure sensor
 Defect of outdoor unit P.C.B. (A1P)
 Defect of thermistor R3T