Navien NCB-180, Service Manual

Page: 93 / 149

90 NCB Service Manual Version 1.0
5.2.4 016Error
Error occurrence conditions and check items
Error Description
E016
Bimetal
overheated
If the overheat controller on the heat exchanger is initiated during combustion/standby of the boiler, the
system displays the 016E (manually cleared) message on the front panel. The boiler switches into Lock-Out,
and performs post-purge continuously and operates the pump.
Check items
1. Check if the overheat controller is working properly.
* Check resistance value or continuity. (refer to page 61)
2. Check the hot water temperature sensor. (refer to page 62)
NO
YES
Is HTL* normally
operating?
* HTL: High Temperature Limit Switch
YES
NO
Is HTL* normally
operating?
Check the resistance between #11 and #12 of
CN 13: short-circuit
1 step: Flushing, Clean Filter
2 step: Try to restart
Replace HTL
Check connector
(#11 and #12 of CON 13)
Measuring should be done at least 30 minutes
after error.