Navien Error Codes & Faults We Repair
E003 — Ignition failure (no spark or no flame detection)
E012 — Flame loss during operation
E016 — Overheating / high limit fault
E030 / E031 — Exhaust or inlet sensor fault
E110 — High temperature limit
E407 — Cold water inlet sensor fault
Flow sensor replacement (no hot water fault)
Condensing heat exchanger descaling
Secondary heat exchanger replacement
Gas valve replacement and calibration
Fan assembly and inducer replacement
PCB (main control board) replacement
Boiler Not Working Right Now?
Call directly for same-day emergency response across York Region. We carry common parts on the truck.
📞 647-699-2474Our Repair Process
- You tell us the error code — if your Navien is showing a fault code, write it down before calling. It tells us exactly what system triggered the lockout and what parts to bring.
- We arrive prepared — as a certified Navien technician, we stock Navien-specific parts: ignitors, sensors, flow sensors, gas valves, and PCBs for the most common NCB and NHB models.
- Live diagnostic on the unit — we read fault history, test combustion, check gas pressure at the manifold, verify flow rates, and inspect the heat exchanger for scale.
- Repair and commissioning — after the repair, we reset the fault log, run a full heat and DHW cycle, check exhaust CO levels, and verify the system is operating within Navien's specified parameters.
- Documentation — we document the fault, parts replaced, and any other observations. Useful for warranty claims or future service history.
Common Questions
E003 means ignition failure — the boiler attempted to ignite but either didn't produce a spark or didn't detect a flame within the trial period. Common causes: failed ignitor electrode, faulty flame sensor, gas supply issue (check that other gas appliances are working), or a clogged burner. Don't keep resetting — repeated failed ignition attempts can flood the heat exchanger with unburned gas. Call us.
E110 is a high temperature limit fault — the boiler reached a temperature above its safety threshold and shut down. Common causes: low system water pressure, blocked pump, closed zone valves limiting flow, or a failing high-limit sensor. Check your system pressure gauge first (should be 12–15 PSI when cold). If pressure is low, add water carefully, reset once, and call us if it trips again.
On Navien combi units (NCB series), yes — the diverter or priority valve is the first thing we check. If domestic hot water isn't triggering properly, it could also be the cold water inlet flow sensor, which tells the boiler when to switch to DHW mode. On Navien units, flow sensor replacement is a common repair that restores hot water without needing a full unit replacement.
Navien recommends annual maintenance. In York Region's hard water areas — especially Richmond Hill, Vaughan, and Markham — scale buildup in the heat exchanger is the most common cause of premature Navien failure. Annual descaling significantly extends unit life. We run a combustion analysis, flush the heat exchanger, test all sensors and the gas valve, and inspect the condensate system at every maintenance visit.
Navien residential boilers come with a 10-year heat exchanger warranty and 5-year parts warranty when installed and serviced by a certified technician. If your unit is within warranty, we document all work and can help support a warranty parts claim with Navien Canada. Keep your original installation paperwork — serial number and install date are required for warranty claims.
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G1 licensed, Navien and NTI certified. York Region's owner-operated boiler specialist — the tech who answers is the tech who shows up.
- ✓ G1 Licensed — all gas boiler work
- ✓ Navien & NTI factory certified
- ✓ All brands and boiler types
- ✓ Same-day for emergencies
- ✓ Upfront pricing — no surprises
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