Panasonic CS-A18CKH Service Manual page 65

13.1.1. Relationship between the condition of the air conditioner and pressure and
electric current
Condition of the air
conditoner
Insufficient refrigerant
(gas leakage)
Clogged capillary tube
or Strainer
Short circuit in the
indoor unit
Heat radiation
deficiency of the
outdoor unit
Inefficient compression
• Carry out the measurements of pressure, electric current, and temperature fifteen minutes after an operation is started.
13.1.2. Diagnosis methods of a malfunction of a compressor and 4-way valve
Nature of fault
Insufficient compressing of a compressor
Locked compressor
Insufficient switches of the 4-way valve
Cooling Mode
Low Pressure High Pressure
• Electric current during operation becomes approximately 20% lower than the normal value.
• 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.
• 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 is a humming sound.
• 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.
Electric current Low Pressure
during operation
Symptom
65
CS-A18CKH CU-A18CKH / CS-A24CKH CU-A24CKH
Heating Mode
High Pressure Electric current
during operation