001Error - Navien NCB-150E Service Manual

5.1.1 001Error

Error occurrence conditions and check items
Error
1. In order to prevent boiler in the heat exchanger, if the space heating water temperature is higher than
E001
Overheating of Heat 2. If the space heating water temperature is lower than 212 °F(100 °C), E001 will be automatically reset and the
Exchanger
3. If overheating occurs three(3) times consecutively, E001 will be displayed and must be manually reset.
1. Check the circulation pump operating status.
2. Check the 3-way-valve operating status.
3. Check if the heating strainer is clogged.
4. Check if the main heat exchanger or the DHW heat exchanger is clogged.
Check items
5. Check the heating inlet/outlet valve and distribution piping for any obstructions.
6. Check the PCB DIP S/W capacity setting.
7. Check if the PCB is operating properly.
8. If the issues continue despite checking the items above, replace the PCB.
86 NCB-E Service Manual
212 °F(100 °C), E001 will be displayed on the front panel.
unit will repeat the combustion cycle.
Verify
thermistor readings at
the front panel. Is the hot
water thermistor readings
normal?
Yes
Verify checkpoints under
Check Items list
Description
NO
Replace the supply thermistor
Resistance between #7 and #8 of CN13 is from
0.437kΩ to 176kΩ at normal condition.
(see page 61 for Wiring Diagram)
Before measuring resistance of the thermistor,
detach the connector from the PCB.
Version 1.4