Navien NFC-175, Service Manual

Page: 84 / 138

84 NFC Service Manual
Version 1.0
5.2.5 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 53).
2. Check the hot water temperature sensor (refer to page 54).
3. Check for proper power supply(120 VAC) to the pump(external).
4. Check for proper resistance at the pump(external).
5. Check if Air Purge is fully done in the system. (If Air Vent is opened?)
Is HTL* normally
operating?
Is the PCB normally
operating?
Check connector
(#13 and #14 of CNJ1)
Replace HTL
Step 1: Flushing, Clean Filter
Step 2: Try to restart
Check the resistance between
#13 and #14 of CNJ1: short-circuit
No
YES
Yes
No
Measuring should be done at least
30 minutes after error.
* HTL: High Temperature Limit Switch