How To Diagnose Faulty Part - Toshiba RAS-24UKHP-ES-1 Service Manual

9-5. How To Diagnose Faulty Parts
[04 Serial signal error] (Heat pump model)
Does outdoor
unit operate?
YES
[08 Four-way valve error] (Heat pump model)
Does four-way valve
operate properly?
YES
Is TC sensor
resistance value
(10kΩ at 25°C) normal?
NO
NO
Are 1, 2 and 3 crossover
wires connected properly?
YES
Is connector
connected properly?
YES
Does LED (Orange) on
outdoor P.C. board blink?
YES
Does LED (Green) on
outdoor P.C. board blink?
YES
Does coil terminal
NO
have 220 − 240 V
in heating operation?
YES
Are circuit
wires normal?
YES
Is outdoor P.C. board
normal?
YES
YES
NO
NO
NO
NO
Outdoor P.C. board
is defective.
Indoor P.C. board
is defective.
YES
Four-way valve
is defective.
NO
NO
Outdoor P.C. board
is defective.
(CN11 220 − 240V)
Indoor P.C. board
is defective.
– 48 –
FILE NO. SVM-03009
Operation
Check item
Conceivable principle cause
Measure
Item by symptoms
Connect crossover
wires properly.
Connect connector
properly.
Replace
P.C. board.
Replace
P.C. board.
Replace
Four-way valve
Circuit check/modification
Replace
P.C. board.
Replace
P.C. board.
Replace TC sensor.