Service manual

– 32 –
2. Water outlet thermistor error.
Check the water outlet thermistor.
• Check to see whether the actual hot-water
temperature and displayed data of maintenance
information monitor no. 31 match.
(1) Measure the resistance between White 1 and
White 2 of connector M64.
Yes Continue to “3. Heat exchanger...”.
No Replace water outlet thermistor.
Temp.(°C)
Resistance( kΩ )
Normal
0 10 20 30 40 50 60 70 80
23.7 15.5 10.3 7.0 4.9 3.5 2.5 1.9 1.4
Check the water inlet thermistor.
• Check to see whether the actual water temperature
and displayed data of maintenance information
monitor no. 30 match.
(1) Measure the resistance bewteen White 1 and
White 3 of connector Q63.
1. Water inlet thermistor error.
C. Hot-water supply temperature cannot be adjusted.
Yes Continue to “2. Water outlet...”.
No Replace the water inlet thermistor.
Temp.(°C)
Resistance( kΩ )
Normal
0 10 20 30 40 50 60 70 80
23.7 15.5 10.3 7.0 4.9 3.5 2.5 1.9 1.4
(2) Measure the voltage between Blue 29 of
connector 38 and Red 9 of connector 63 on the
circuit board.
Normal
DC 4V or more
No
• Check the clogging of drain piping,
drain trap and connection hose.
• Replace the circuit board.
Yes Replace the circuit board.