Navien Boiler Error Codes — Meanings, Causes & Repair in Greater Vancouver

Seeing a fault code on your Navien boiler? This guide explains what the most common Navien boiler error codes mean, what’s safe to check yourself, and when to call HeatLand’s licensed, TSBC-certified gas technicians for Navien boiler repair across Metro Vancouver and the Fraser Valley.

The codes below apply across common Navien models (NPE, NCB, NHB, NFC, NPN). Meanings follow Navien’s documented fault codes — always confirm against your unit’s own manual, because exact wording can vary by model, control board and firmware.

How to read Navien boiler error codes

Navien displays a letter 'E' followed by a 3-digit number (e.g. E003, E109, E352) on the front-panel display or wired/NaviLink remote controller. Some codes carry an internal subcode that narrows the fault. Code numbering is consistent across most NPE, NCB, NHB, NFC and NPN models, though a few descriptions vary slightly by series and firmware.

Navien boiler error codes & what they mean

These are the Navien boiler codes our Greater Vancouver technicians see most. Anything marked pro repair involves gas, electrical, sealed-combustion or control-board work that must be done by a licensed gas technician (TSBC-certified in BC) — never open gas or electrical components yourself.

Code	What it usually means	Common causes	Safe to check yourself
E001	Overheating of heat exchanger (high-limit trip) pro repair	restricted water flow; scaled/clogged heat exchanger; low system water flow	confirm system water pressure gauge reads in the normal 12-25 psi range; make sure isolation valves are open; power-cycle/reset once
E003	Ignition failure (unit failed to establish a flame) pro repair	no gas supply / gas valve closed; low gas pressure; faulty igniter or flame rod	confirm the gas supply is turned on; check that other gas appliances in the home work; confirm the unit has power
E004	False flame detection (flame sensed when there should be none) pro repair	loose or missing ground wire; moisture or contamination on the flame rod; faulty flame sensor	confirm the unit has power; press the reset button once
E012	Flame loss (flame went out during operation) pro repair	interrupted or low gas supply; dirty flame rod; loose ground wire	confirm the gas supply is on and other gas appliances work; check that the intake/exhaust vent terminals outside are clear of snow, ice or debris; press the reset button once
E016	Overheating of heat exchanger pro repair	scale buildup / restricted flow in heat exchanger; clogged cold-water inlet filter; low water flow	confirm system water pressure gauge is in the normal range; make sure water shutoff/isolation valves are fully open; power-cycle/reset once
E030	Abnormal exhaust (flue) temperature / exhaust overheat pro repair	scaled or partially blocked heat exchanger; improper venting; exhaust thermistor fault	check that the outside vent terminals are clear of obstructions; press the reset button once
E046	Abnormal operation of the heat exchanger overheating (high-limit) sensor pro repair	faulty or disconnected high-limit/overheat sensor; wiring fault; PCB issue	press the reset button once
E047	Abnormal operation of the exhaust thermostat / exhaust thermistor (open or short) pro repair	disconnected or faulty exhaust thermistor; wiring open or shorted; PCB issue	press the reset button once
E060	Abnormal operation of the dual venturi limit switch pro repair	faulty dual venturi limit switch; gas/air mixture fault; wiring fault	press the reset button once
E109	Abnormal fan motor operation pro repair	seized or failing fan motor; obstructed fan; clogged intake air filter	check that the outside intake/exhaust vent terminals are clear of debris, snow or ice; press the reset button once
E110	Exhaust blockage / abnormal air pressure (vent or condensate blockage detected) pro repair	blocked or restricted intake/exhaust vent; clogged or frozen condensate drain; improper vent length/configuration	check that the intake and exhaust vent terminals outside are clear of snow, ice, leaves or nests; confirm the condensate drain line is not clogged or frozen; press the reset button once
E127	Abnormal operation of the air pressure sensor (APS) pro repair	faulty air pressure sensor; blocked sensing tube; venting restriction	check that outside vent terminals are clear; press the reset button once
E205	Heating (central heating) supply thermistor open or short circuit pro repair	disconnected or faulty CH supply thermistor; wiring open/short; PCB issue	press the reset button once
E218	Heating (central heating) return thermistor open or short circuit pro repair	disconnected or faulty CH return thermistor; wiring open/short; PCB issue	press the reset button once
E302	Low water pressure in the heating/system loop pro repair	system needs topping up (water lost over time); leak in heating system; faulty water pressure sensor or auto feeder valve	read the system water pressure gauge — if it is below ~12 psi the system is low; look for any obvious water leaks around the unit and on visible piping; press the reset button once
E351	Abnormal auto feeder valve / make-up water (valve ran to add water but pressure was not restored) pro repair	system leak so make-up water cannot maintain pressure; faulty auto feeder/make-up valve; closed make-up water supply	read the system water pressure gauge; look for visible leaks around the unit and piping; press the reset button once
E352	High water pressure in the system pro repair	system overfilled; faulty/stuck auto feeder valve adding water; failed expansion tank	read the system water pressure gauge (normal is roughly 12-25 psi); press the reset button once
E353	Abnormal operation of the water pressure sensor pro repair	faulty water pressure sensor; wiring fault; PCB issue	press the reset button once
E407	Domestic hot water (DHW) outlet thermistor open or short circuit pro repair	disconnected or faulty DHW outlet thermistor; wiring open/short; PCB issue	press the reset button once
E421	Domestic hot water (DHW) / cold water inlet thermistor open or short circuit pro repair	disconnected or faulty inlet thermistor; wiring open/short; PCB issue	press the reset button once
E438	Abnormal operation of the recirculation pump pro repair	faulty check valve(s); defective flow sensor; damaged or seized recirculation pump	press the reset button once
E515	Abnormal operation of the PCB (relay feedback) pro repair	faulty control board (PCB); relay failure; internal wiring fault	press the reset button once
E517	Abnormal DIP switch setting on the PCB pro repair	incorrect DIP switch configuration; DIP switch set for wrong model/gas/altitude; PCB issue	press the reset button once
E594	Abnormal operation of the EEPROM (PCB memory) pro repair	corrupted or failed EEPROM/control board memory; PCB fault	press the reset button once
E615	Abnormal operation of input and memory (MCU) pro repair	microcontroller/PCB fault; internal memory error	press the reset button once
E740	Abnormal operation of the outdoor temperature sensor pro repair	disconnected or faulty outdoor reset sensor; wiring fault; PCB issue	press the reset button once
E777	Abnormal operation of the low water cut-off (LWCO) pro repair	low system water level/pressure; faulty LWCO device or wiring	read the system water pressure gauge; look for visible leaks around the unit; press the reset button once
E782	Abnormal main panel / display communication pro repair	loose or damaged communication wiring between display and main PCB; faulty display panel or PCB	press the reset button once
E783	Abnormal operation of the OpenTherm remote control pro repair	OpenTherm thermostat/remote wiring fault; incompatible or faulty remote control; PCB issue	confirm the thermostat is set to call for heat; press the reset button once
E788	Abnormal gas type setting pro repair	unit configured for wrong gas type (NG vs LP); incorrect DIP/parameter setting after conversion	press the reset button once

Navien boiler codes we get called for most

E003 — Ignition failure (unit failed to establish a flame)

Typical causes include no gas supply / gas valve closed; low gas pressure; faulty igniter or flame rod. A few things are safe to check yourself (confirm the gas supply is turned on; check that other gas appliances in the home work), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes E003 on Navien boilers throughout Greater Vancouver.

E012 — Flame loss (flame went out during operation)

Typical causes include interrupted or low gas supply; dirty flame rod; loose ground wire. A few things are safe to check yourself (confirm the gas supply is on and other gas appliances work; check that the intake/exhaust vent terminals outside are clear of snow, ice or debris), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes E012 on Navien boilers throughout Greater Vancouver.

E110 — Exhaust blockage / abnormal air pressure (vent or condensate blockage detected)

Typical causes include blocked or restricted intake/exhaust vent; clogged or frozen condensate drain; improper vent length/configuration. A few things are safe to check yourself (check that the intake and exhaust vent terminals outside are clear of snow, ice, leaves or nests; confirm the condensate drain line is not clogged or frozen), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes E110 on Navien boilers throughout Greater Vancouver.

E001 — Overheating of heat exchanger (high-limit trip)

Typical causes include restricted water flow; scaled/clogged heat exchanger; low system water flow. A few things are safe to check yourself (confirm system water pressure gauge reads in the normal 12-25 psi range; make sure isolation valves are open), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes E001 on Navien boilers throughout Greater Vancouver.

Is it safe to keep running a Navien boiler with a fault code?

Most Navien fault codes put the boiler into a safe lockout for a reason. You can safely check the basics — gas supply on, power on, the thermostat calling for heat, system pressure in the normal range, and the condensate drain not frozen or blocked (a common cause in Vancouver cold snaps) — and restart it once. If the code returns, stop and book a technician. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911.

Navien boiler repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair Navien boilers — ignition faults, flame and sensor errors, low-pressure and pump problems, fan and flue faults, and control-board issues — including units we didn’t install. We’re brand-agnostic, carry common parts, and give you an honest repair-or-replace assessment with upfront pricing and a free estimate. If your boiler is beyond economical repair, we’ll show you right-sized, high-efficiency replacement options and the rebates available.

Need it sorted fast? We offer priority emergency boiler repair. Explore Boiler services, browse all boiler error codes by brand, or request a free estimate.

Navien boiler service areas

We repair Navien boilers across Greater Vancouver and the Fraser Valley, including:

Navien boiler error code FAQs

Can I reset my Navien boiler myself?

Yes — power-cycling the reset button once is generally safe after you’ve checked the basics (gas supply on, power on, the thermostat calling for heat, system pressure in the normal range, and the condensate drain not frozen or blocked (a common cause in Vancouver cold snaps)). If the boiler faults again right away, stop and note the code — repeatedly resetting a boiler that keeps locking out can mask a real problem. Call a licensed, TSBC-certified gas technician to diagnose it.

What does the Navien E003 code mean?

On Navien boilers, E003 commonly indicates ignition failure (unit failed to establish a flame). Confirm the exact meaning against your unit’s manual — codes can vary by model and series — and have the repair done by a licensed, TSBC-certified gas technician. HeatLand fixes this across Greater Vancouver.

Do you repair Navien boilers you didn’t install?

Yes. HeatLand is brand-agnostic and services Navien boilers throughout Metro Vancouver and the Fraser Valley, whether or not we installed the unit. We carry common parts and give you an honest repair-or-replace assessment.

Is a Navien boiler fault code an emergency?

No heat in cold weather is worth treating urgently. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911. For priority boiler repair across Greater Vancouver, call (604) 330-3812.

How much does Navien boiler repair cost in Vancouver?

It depends on the fault. Many Navien codes point to sensors, ignition or pump parts — usually far cheaper than replacement. We give upfront pricing and a free estimate before any work.

More Boiler error-code guides

HeatLand repairs every major boiler brand across Greater Vancouver. More brand guides: