Si30-408
Malfunction Tree Analysis (FTA)
Troubleshooting
97
4.1
Actuation of Freeze-up Prevention Control of Indoor Unit
Freeze-up
prevention control
Heat exchanger
temperature drops
(Evaporating
temperature drop)
False detection of
heat exchanger
temperature
Faulty compressor
capacity control
Faulty design
(Soft miss)
Refrigerant
circulation
volume low
Evaporation
capacity too
small
Faulty liquid pipe
thermistor
Faulty control
PC board
False detection
of pressure
Faulty actuation
of expansion
valve
Piping resistance
high
Run out of gas
Dirty evaporator
Load
too small
Air flow
drop
Faulty control PC board
Faulty low
pressure sensor
Faulty
expansion
valve
Faulty
control
Abnormal
piping length
Warp · Collapse
Foreign
matter clog
Faulty
selecting
model
Outside of
application
scope
Operation
capacity low
Fan output drop
Ventilation path
resistance high
Faulty driving
part
Faulty sensor
Faulty control
board
Faulty valve
body
Faulty
therrmistor
Short
circuit
Faulty control
PC board
Latent heat
load too small
Faulty fan motor
Faulty control PC
board
(Including
capacity setting)
Dirty filter
Obstruction