Multi F Four-Way Ceiling Cassette Service Manual

Part 5. Trouble Shooting
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Only for training and service purposes
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Display
code
Title Cause of error Check point & Normal condition
35 Low Presser Error
Excessive decrease of low
pressure
• Defective low pressure sensor
• Defective outdoor/indoor unit fan
• Refrigerant shortage/leakage
• Deformation because of damage of refrigerant pipe
• Defective indoor / outdoor unit EEV
• Covering / clogging (outdoor unit covering during
the cooling mode / indoor unit filter clogging dur-
ing heating mode)
• SVC valve clogging
• Defective outdoor unit PCB
• Defective indoor unit pipe sensor
■ Error diagnosis and countermeasure flow chart
Is service valve
opened?
Open service valve
Are communication cable/
piping normal?
Yes
No
Is amount of refrigerant
normal?
[refer refrigerant part]
Yes
No
Adjust the amount of
refrigerant (Additive charge)
check communication/
piping correction.
Is strainer Ok?*
No
Replace the strainer
No
Replace the pressure sensor
Yes
Yes
Check indoor / outdoor unit LEV
Check Indoor unit PCB
Check indoor / outdoor unit
installation conditions
Yes
Is there pipe crack or trace
of refrigerant leakage?
Weld / reconnect the cracked
portion and recharge refrigerant
No
Yes
* If the temperature difference between inlet and outlet of strainer
is so large that frost or ice formation can be seen or confirmed
then clogging of strainer should be checked
(Notice: it is not full ice forming of strainer, in case that there is
not at inlet portion but at outlet portion)
Are the value of manifold
gauge and pressure
sensor same?
(Is the low pressure value
actually low?)