Navien E515: Main Control (MICOM) Abnormal
What the Navien E515 error code means, what causes it, and why it's a job for a licensed BC gas technician — not a DIY reset.
Severity
Moderate — book a service visit
What the Navien E515 error code means
The boiler detected an internal main-control (microprocessor) abnormality.
On Navien NCB-E, NCB-H, NHB, NFB and NPE-A2 series, E515 is a control-board (pcb) fault. It is a protective response — the boiler is telling you something needs attention, and the safe, lasting fix is a proper diagnosis rather than repeated resets.
Symptoms you may notice
- Boiler unresponsive or erratic
- Multiple unrelated faults at once
- Display errors that persist after reset
Common causes of Navien E515
Why this is not a DIY fix
A genuine control-board fault should only be declared after sensors, wiring and power have been ruled out — boards are expensive and are often blamed wrongly. A technician confirms the board has truly failed before replacing and re-commissioning it.
In British Columbia, gas work must be performed by a TSBC-licensed gas fitter. GasBoilers.ca — a CanroHeat division — sends Red Seal–certified, gas-licensed technicians who diagnose the true cause, repair it correctly, and verify safe operation before they leave.
How our technicians diagnose & repair it
- 1Rule out sensors, wiring, power and grounding first
- 2Check board fuses, relays and output signals
- 3Confirm correct firmware/dip-switch and model configuration
- 4Replace and re-commission the board, then verify all functions
Related Navien codes
Navien E515 — FAQ
What does the Navien E515 error code mean?
The boiler detected an internal main-control (microprocessor) abnormality. On Navien NCB-E, NCB-H, NHB, NFB and NPE-A2 series, this is categorised as a control-board (pcb) fault.
What causes Navien E515?
The most common causes are: Control-board fault; Power-supply disturbance; Firmware/grounding issue. A licensed technician confirms which one applies before any part is replaced.
Can I fix Navien E515 myself?
No. A genuine control-board fault should only be declared after sensors, wiring and power have been ruled out — boards are expensive and are often blamed wrongly. A technician confirms the board has truly failed before replacing and re-commissioning it. Repeatedly resetting the boiler without fixing the root cause can be unsafe and can cause further damage. Call GasBoilers.ca at 604-359-1081 for a licensed diagnosis.
Is the Navien E515 error code dangerous?
This is a protective fault — the boiler has shut down a function to protect itself. It is best diagnosed promptly by a licensed technician so the underlying cause does not lead to a more expensive failure.
How much does it cost to fix Navien E515 in Greater Vancouver?
Cost depends on the root cause and any parts needed. We start with a flat-rate diagnostic, then quote the repair before any work begins — no surprises. Call 604-359-1081 for current pricing and same-day availability.
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Navien showing E515? We'll fix it right.
Licensed, Red Seal–certified gas technicians across Greater Vancouver. Upfront pricing, same-day service available.