Toshiba HWS-P805XWHM3-E(TR) Service Manual page 102

[A11] Error Release protection operation
Start
Flow switch is normal
Yes
Excess air
noise comes from
inside pump
No
Chattering
noise comes from
flow switch
No
TWI sensor is
attached to pipe
Yes
TWI and TWO
sensor characteristics
are normal
Yes
Replace water heat
exchange control board
No
Yes
Secure water
circulation amount
Yes
Circulation flow
shortage
No
No
Remove sufficiently
excess air
Waste stuck inside
water circuit
12 M or longer water
pipe to a branch,
or 5 or less branches
101
Replace flow switch
Remove waste
Place buffer tank and
the second pump
Attach TWI sensor
Replace TWI or TWO sensor