Toshiba MMW-AP0481CHQ-E Service Manual page 67

Check code Check code name
Activation of water heat
exchanger frost
[A04]
protection
(H-HWM)
Are characteristics
of TWI (TA) and TWO
(TC2) sensor resistance
normal ?
Is H-HWM ambient
temperature within the
use range ?
H-HWM ambient temperature decrease
H-HWM control P.C. board trouble
TWI (TA) sensor trouble
TWO (TC2) sensor trouble
NO
YES
NO
YES
Cause
– 67 –
Replace TWI (TA) or
TWO (TC2) sensor.
Install H-HWM and water
pipes in the freeze-free
place.
Check H-HWM control
P.C. board.
Failure → replace