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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.
$99 dispatch and diagnosis fee — waived if you approve the repair
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.
Need Navien repair on the South Shore?
An error-code guide can explain the symptom. If your home is in Hull, Quincy or our surrounding South Shore service area, Johnson Bros. can help with the next step: diagnosing your Navien boiler, combi boiler or tankless water heater.
The house has no heat
Tell us whether every room is cold or just one heating zone, and whether the boiler display shows a code.
Boiler and no-heat repairThe taps have no hot water
Check whether it affects one fixture or every hot tap. Tell us if you have a tank, a tankless heater, or a boiler that also heats your water.
Help with no hot waterBoth stopped working
Mention both symptoms when you call, especially with a combi boiler. Have the brand, model and displayed code ready if you can read them safely.
Navien service and repairCalls are answered 24/7. Call for urgent no-heat or no-hot-water trouble; we will confirm appointment availability. Online booking does not guarantee immediate dispatch.
Local service: Hull heating repair · Quincy · Weymouth · Hingham · Braintree · Abington.
Smell gas? Leave the house first, then call the gas utility or 911 from outside. Do not use switches, phones or anything that sparks inside the building, and do not go looking for the source. Call us afterwards, once it is safe, for the repair.
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.
Can't talk right now? Get a callback.
Related services
All Navien error codes
The other codes this unit can show, and what each one means.
Navien service and repair
Installation, service and repair for Navien equipment on the South Shore.
Water heater repair and replacement
Repair and replacement options for tank and tankless water heaters.
Family Plan
Members get 10% off, priority scheduling, and the $99 fee waived even if you decline the quote.
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Upfront Options
You get a clear explanation of the work and price before the job begins.
Repair-First Guidance
We help you understand whether repair, replacement, or follow-up service makes the most sense.
Navien E515 diagnosed properly
We diagnose the cause rather than clearing the code and hoping. You get an upfront price before any work starts.
Call for urgent help now. Book online when you want the next available fit for your schedule.