8-4.Diagnosis Flow Chart For Each Check Code; 8-4-1.Hydro Unit Failure Detection - Toshiba HWT-602S21SM3W-E(TR) Service Manual

8-4. Diagnosis flow chart for each check code
8-4-1. Hydro unit failure detection
[A01] Flowing quantity failure
Perform air vent
Yes
2-3 minutes after its
Check water heat exchange
[A01] occurs
Operation restarts
No
Built-in circulation
pump rotates
Yes
Excess air noise
comes from inside
the pump
No
Pump stops
Yes
rotation started
No
Flow shortage
detected by flow sensor
is almost same as
PC board
control board
MCC-1753
If defective, replace it
Pump is connected
to board
Yes
(Identify causes, and resolve)
Flow rate
No
actual value
Yes
Dirt clogging inside
water circuit
12M or longer water
pipe to a branch,
5 or less branches
122
No
Connect pump
connector to board
Replace the pump
Replace the flow sensor
Remove waste
Fit buffer tank and
the second pump