How To Diagnose Faulty Parts - Toshiba RAS-18UFHP-E Service Manual

9-5. How to Diagnose Faulty Parts

[04 Serial signal error]
Does outdoor
unit operate?
YES
[08 Four-way valve error]
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?
NO
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.
– 54 –
FILE NO. SVM-02008
Operation
Check item
Conceivable principle
cause
Measure
Item by symptoms
Connect crossover
wires properly.
Connect crossover
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.