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Navien E515 — Control Board (PCB) Fault
Your Navien's control board flagged an abnormal condition in itself or a part it monitors. It's a protective lockout that points to the PCB and its connected components.
E515 is a control-board (PCB) fault. The board runs continuous self-checks and monitors key components — the igniter, fan, gas valve, and venturi among them. When it detects a condition it can't reconcile, it posts E515 and locks the unit out as a safety measure.
Sometimes the board itself has failed; other times a component it watches, or a loose connection to it, is the real problem. Because the board sits at the center of everything, E515 needs methodical diagnosis — we check connections and monitored parts before condemning the PCB, since the board is one of the pricier components.
What causes E515
1. Control-board (PCB) failure
The board itself can fail after years of heat and electrical cycling. When testing confirms it, replacement restores the unit.
2. A monitored component faulting
The board watches the igniter, fan, dual venturi, and 3-way valve. A fault in one of those can surface as E515 — so we test them before replacing the board.
3. Loose or corroded connectors
A poor connection at the board can mimic a board failure. Reseating and cleaning connections sometimes clears it outright.
4. Power-supply irregularity
Unstable incoming power or a grounding issue can upset the board's self-checks. We verify clean power as part of the diagnosis.
What you can safely check first
- Note anything that changed just before the code appeared: a power outage, a surge, water near the unit. It genuinely narrows the diagnosis.
- One reset is reasonable. If E515 returns straight away it is reporting a real condition rather than a glitch.
When to stop and call us
The board is one of the more expensive parts on a Navien, so a proper E515 diagnosis tests the monitored components and the connections first. Sometimes a reseated connector or a cheaper monitored part clears it without a new board.
Seeing E515 on your Navien?
Book online and we will diagnose the actual cause, explain what we find, and price the repair before starting.
Navien E515 FAQs
What does Navien error code E515 mean?
E515 is a control-board (PCB) fault. The board continuously checks itself and the components it drives; when it detects a condition it cannot reconcile, it locks the unit out and posts E515 as a safety measure.
What causes E515?
Either the board itself has failed, or a component it monitors — the igniter, fan, dual venturi, or 3-way valve — has faulted, or a connector to the board is loose or corroded. A power-supply or grounding irregularity can also upset the board.
Do I need a new control board for E515?
Not necessarily. The board is one of the more expensive parts, so a proper E515 diagnosis tests the monitored components and the connections first. Sometimes reseating a connector or replacing a cheaper monitored part clears it without a new board.
How much does E515 repair cost?
The $99 service fee sends a licensed technician out to diagnose the problem. Approve the repair on the spot and the fee is not charged at all; decline it and the $99 covers the visit. Cost depends on what testing finds — a connector or a monitored part is modest; a replacement control board is a larger, quoted repair we confirm with you first.
Other codes on this unit? See all Navien error codes.
Why South Shore homeowners choose Johnson Bros.
Navien E515 diagnosed properly
We diagnose the cause rather than clearing the code and hoping. You get an upfront price before any work starts.
Not sure what's wrong? Send a photo or videoBooking online is the quickest way to hold the next open appointment. Call instead if it is urgent and you would rather talk to someone.
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Navien E515 diagnosed properly
We diagnose the cause rather than clearing the code and hoping. You get an upfront price before any work starts.
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