Panasonic CS-PW18GKE, Service Manual, Page: 40 / 53

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14.2. Relationship Between The Condition Of The Air Conditioner And
Pressure And Electric Current
• Carry out the measurements of pressure, electric current, and temperature fifteen minutes after an operation is started.
14.3. Diagnosis Methods Of A Malfunction Of A Compressor And 4-way Valve
Cooling Mode Heating Mode
Condition of the
air conditoner Low Pressure High Pressure Electric current
during operation
Low Pressure High Pressure Electric current
during operation
Insufficient refrigerant
(gas leakage)
Clogged capillary tube or
Strainer
Short circuit in the indoor
unit
Heat radiation deficiency of
the outdoor unit
Inefficient compression
Nature of fault Symptom
• Electric current during operation becomes approximately 20% lower than the normal value.
Insufficient compressing of a compressor • The discharge tube of the compressor becomes abnormally hot (normally 70 to 90
°
C).
• The difference between high pressure and low pressure becomes almost zero.
Locked compressor
• Electric current reaches a high level abnormally, and the value exceeds the limit of an
ammeter. In some cases, a breaker turns off.
• The compressor has a humming sound.
Insufficient switches of the 4-way valve
• Electric current during operation becomes approximately 80% lower than the normal value.
• The temperature different between from the discharge tube to the 4-way valve and from
suction tube to the 4-way valve becomes almost zero.