Navien CH-180, Service Manual, Page: 89 / 155

87
Error occurrence conditions and check items
5.16. 16Error
Error Description
If the high limit switch cutoff on the heat exchanger is sensed to be 197
ı
or higher
continuously for 1 second at combustion/stop of the boiler, the system displays the
16E (manually cancelled) heat exchanger high limit switch cut-off message on the
remote controller. The boiler switches into Lock-Out, and performs post-purge
continuously.
1. Check the heating supply/return valve.
2. Check if the heating strainer is clogged.
3. Check the circulation pump operating status.
4. Check if the high limit switch is defective.
5. Check if the thermal fuse is disconnected.
6. Check the heating supply temperature sensor.
7. Check if the heat exchanger or the DHW heat exchanger is clogged.
8. Check if the heat exchanger is defective.
16E
High Limit
Switch
Cut-off
Check
items
Is HTL
*
normally operating?
Yes
No
Replace HTL
Check the resistance between two white wires of CN 13: short-circuit (016E)
Check the resistance between two brown wires of CN 13: short-circuit (030E)
Replace PCB
Caution : Measuring should be done at least 30 minutes after error.
*HTL: High Temperature Limiter
© Navien Ameri c a I n c . 20 1 0 CH series servi c e Manua l Version 1 .0