Navien NP Condensing Tankless Gas Water Heater - Service Manual

5.11. 16Error
Error occurrence conditions and check items.
Error
Description
16E
Bimetal
overheated
If the overheat controller on the heat exchanger operates during combustion
stop of the boiler, the system displays the 16E (manually cleared) message on the
remote controller and the PCB. The boiler switches into Lock-Out, and performs
postpurge continuously and operates the pump.
If the overheat sensor signal is detected within 10 min after the combustion is
stopped, no error is displayed, and the system does not start combustion until the
overheat sensor is returned to normal.
Check items
1. Check if the main heat exchanger is clogged.
2. Check if the overheat controller works properly.
3. Check the hot water output/input temperature sensor.
4. Check the PCB DIP S/W capacity setting.
5. Check if the PCB works properly.
Is HTL* normally operation?
No
Replaace HTL
Yes
Replace PCB
Check the resistance betweenteo white wires of CN 13:
short-circuit(016E)
Check the resistance betweenteo white wires of CN 13:
short-circuit(030E)
Caution: Measuning should be done at leat 30 minutes
after error.
©Navien America Inc. 2010
92
NR/NP series service Manual
Version 2.0