Navien Combi Boiler Error Codes
Navien NCB, NPE and NHB combi boilers display an 'E' fault code on the front panel and through the NaviLink app. Note the exact code and your model number before calling.
This is not a DIY repair
Combi boilers are gas-fired appliances regulated under the BC Safety Standards Act. Opening the unit, touching the gas valve, or working on the flue without a valid BC gas-fitter licence is both unsafe and illegal. Diagnosing the fault is helpful — fixing it should always be left to a certified technician.
Call 778-909-5731Navien fault codes (19)
E003UrgentIgnition failure — the boiler tried to light but no flame was detected.E004UrgentFalse flame detected — the boiler senses a flame when it should be off.E012UrgentFlame loss during operation — the burner lit but the flame was lost.E016UrgentOverheating — water temperature exceeded the safe limit.E030UrgentExhaust (flue) temperature too high.E041ModerateWater flow sensor / low flow fault on the DHW side.E047UrgentAir pressure / APS fault — combustion air or flue pressure out of range.E109UrgentFan fault — the combustion fan is not running at the commanded speed.E110UrgentOverheat / high-limit lockout triggered.E202ModerateInlet/return water temperature sensor fault.E207ModerateOutlet (supply) water temperature sensor fault.E301ModerateDHW (domestic hot water) temperature sensor fault.E351ModerateCommunication error between control board and display.E438ModerateMixing valve / 3-way valve fault.E441ModerateLow water flow rate detected during heating.E515UrgentControl board (PCB) error.E517ModerateDip switch / configuration setting error.E594ModerateCascade communication fault (multi-unit systems).E760LowNaviLink Wi-Fi communication fault.