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240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
Error Code
Malfunction description
Cancellation method
321
Disconnected/short-circuited inlet thermistor
Turn off the power or water supply
Diagnosis
Check point
1 Inlet thermistor fault
(Refer to section 10-12)
Visual inspection: connection/breakage of wires and/or debris on
thermistor.
Check voltage/resistance between black & black (#42).
Refer to Section 8 (A) for proper range of values.
E2
Error Code
Malfunction description
Cancellation method
331
Disconnected/short-circuited outlet thermistor
(Only 540 (T-H3) models)
Turn off the power or water supply
Diagnosis
Check point
1 Heat exchanger thermistor fault
(Refer to section 10-12)
Visual inspection: connection/breakage of wires and/or debris on
thermistor.
Check voltage/resistance between black & black (#12).
Refer to Section 8 (A) for proper range of values.
E3
Error Code
Malfunction description
Cancellation method
391
Disconnected AFR rod
Turn off the power or water supply
Diagnosis
Check point
1 AFR rod fault
(Refer to section 10-6)
Visual inspection: connection/breakage of wires, soot on it.
I
Error Code
Malfunction description
Cancellation method
341
Disconnected/short-circuited exhaust thermistor
(Only Direct Vent Indoor models only)
Turn off the power or water supply
Diagnosis
Check point
1 Exhaust thermistor fault
(Refer to section 10-13)
Visual inspection: connection/breakage of wires and/or debris on
thermistor.
Check voltage/resistance between white & white.
Refer to Section 8 (B) for proper range of values.
K1