07Error - Navien NP-180 Service Manual

5.2. 07Error

Error occurrence conditions and check items.
Error
1. Pre ignition false-flame
If a flame signal is detected continuously for 6 seconds before combustion
(stand-by, pre-purge, pre-ignition), a false-flame error 04E (automatically cleared)
is dis-played on the thermostat, and the system performs continuous post-purge
07E
and operates the pump.
Hot water
2. Post purge false-flame
temperature
If a flame signal is detected continuously for 6 seconds when the system performs
sensor open
post-purge as fuel supply is stopped, a false-flame error 04E (automatically cleared)
is displayed on the thermostat, and the system performs continuous post-purge
and operates the pump.
1. Check if gas leaks due to defective air sealing of the gas block.
2. Check if electricity is discharged from the electrode.
Check items
3. Check if gas is supplied at higher pressure than the standard gas pressure.
4. Defective PCB.
Is the hot water thermistor
normal?
Yes
Check connector
©Navien America Inc. 2010
Description
No Replace hot water thermistor
Resistance between two red wires of CN 13 is from
0.8 to 20k ohm at normal condition.
Caution: B efore measuring resistance of the
thermistor, remove the connector from the PCB
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NR/NP series service Manual Version 2.0