©Navien America Inc. 2010 NR/NP series service Manual77Version 2.05.2. 07ErrorError occurrence conditions and check items.DescriptionError07EHot watertemperaturesensor openCheck items1. Pre ignition false-flameIf 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-purgeand operates the pump.2. Post purge false-flameIf a flame signal is detected continuously for 6 seconds when the system performspost-purge as fuel supply is stopped, a false-flame error 04E (automatically cleared)is displayed on the thermostat, and the system performs continuous post-purgeand operates the pump.Is the hot water thermistornormal?YesNoCheck connectorReplace hot water thermistorResistance between two red wires of CN 13 is from0.8 to 20k ohm at normal condition.Caution: B efore measuring resistance of thethermistor, remove the connector from the PCB1. Check if gas leaks due to defective air sealing of the gas block.2. Check if electricity is discharged from the electrode.3. Check if gas is supplied at higher pressure than the standard gas pressure.4. Defective PCB.
