Navien NCB-180, Service Manual

Page: 97 / 149

94 NCB Service Manual Version 1.0
5.2.6 046Error
Error occurrence conditions and check items
5.2.7 047Error
Error occurrence conditions and check items
Replace exhaust thermistor
Yes
Is exhaust thermistor
operating normally?
Check connector
(#9 and #10 of CN13)
NO
Resistance between #9 and #10 of CN13 is from 2k
Ω
to 300k
Ω
at normal condition. (see page 56 for
Wiring Diagram)
Is heat exchanger
thermistor normally
operating?
1 step: Flushing, Clean Filter
2 step: Try to restart
3 step: Replace PCB
NO
Yes
Replace heat exchanger
thermistor.
Is resistance
within normal range?
(refer to page 62)
Check connector
( #3 and #4 of CN 13)
Yes
NO