Toshiba HWT-602S21SM3W-E(TR) Service Manual page 134

[E04] Regular communication failure between hydro unit and outdoor unit
Outdoor unit failure occur
(Check the display board
of outdoor unit)
Solve the outdoor unit
failure
[F03] TC sensor failure
Start
TC sensor
connector (CN601) is
connected
TC sensor
resistance characteristic
is normal
Check water
heat exchange
control board
If defective, replace it
No
Yes
connecting between outdoor
TB01 terminal block (1, 2, 3)
on again, D503 (Yellow LED)
If defective, replace it
No
Yes
No
Yes
PC board
MCC-1753
The wiring and
No
unit and hydro unit
are correct
Yes
Hydro unit
CN01 connector and
No
wiring are correct
Yes
When power is
No
Flashes
Yes
Check water
heat exchange
control board
PC board
MCC-1753
133
Correct wiring and
connecting wire
Correct connector and
terminal block wiring
Check outdoor
control board
If defective, replace it
PC board
<401,601> MCC-1768
<801,1101> MCC-1675
(3 phase)<801,1101,1401>
MCC-1781
Correct TC sensor
connection
Replace TC sensor