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    Johnson Bros. Plumbing & Drain Cleaning

    Navien Service, Repair & Annual Maintenance

    Error code on the front panel? No hot water on a Saturday morning? Original installer ghosted you? We diagnose the root cause, fix what is actually broken, and get you on a real annual service schedule.

    Johnson Bros. — Quincy & Abington offices. $99 service fee applies toward the work.

    Call (617) 479-9911Book Service
    4.8 stars on Google · 367 reviews across Quincy and AbingtonMA Lic. PL #17034-MEmergency calls 24/7Quincy & Abington offices

    What a Real Navien Service Visit Covers

    Heat exchanger descale (flush)

    Pump cleaning solution through the heat exchanger for 45–60 minutes. Scale is the #1 killer of tankless units. Annual descaling is the most important service task.

    Inlet water filter cleaning

    Remove, inspect, rinse. Grit collects here and restricts flow if ignored.

    Flame rod inspection

    Flame rod fouling causes ignition codes (E003, E004). We clean or replace if needed.

    Combustion analysis

    We verify CO and O2 are within spec. This is how you know combustion is actually correct, not just that the unit fires.

    Condensate trap & drain check

    Blocked condensate trips lockouts. We clean the trap and verify the neutralizer media.

    Error log review

    We pull the Navien error log and look at what the unit has been telling you even if you missed it.

    Common Navien Error Codes We Handle

    E003
    Ignition failure

    Gas valve, flame rod, venting, or low gas pressure. See our E003 page for details.

    E012
    Flame loss during operation

    Flame rod fouling, gas pressure, or combustion air. See E012 page.

    E027
    Outlet water temp sensor

    Sensor or wiring. Straightforward diagnostic. See E027 page.

    E016
    High exhaust temperature

    Scaling or reduced water flow through the heat exchanger. Usually a descale.

    E040
    Gas pressure fault

    Low gas supply pressure. Often a gas-sizing issue, not a unit problem.

    A012
    Air intake fault

    Venting obstruction or damper issue.

    Common Questions About Navien Service

    My Navien is throwing an error code — can you service it?
    Yes. We service all current Navien residential models — NPE tankless water heaters and NCB/NFB combi boilers. Call (617) 479-9911, tell us the model (it's on the side label) and the code, and we'll tell you whether it's something to treat as emergency or standard diagnostic.
    How often does a Navien need maintenance?
    Every 12 months. That visit includes flushing and descaling the heat exchanger, cleaning the inlet water filter, inspecting the flame rod and condensate trap, and verifying combustion is in spec. In hard-water areas of the South Shore, descaling may be needed more often.
    What happens if I skip annual service?
    Scale buildup in the heat exchanger is the #1 reason tankless units fail early. Skipped service leads to reduced flow, error codes, short-cycling, and in the worst case, a ruined heat exchanger — which is close to the cost of replacing the whole unit. Annual service is cheap insurance.
    Can you take over service on a Navien the original installer no longer supports?
    Yes. We do take-over service on existing Navien units. We start with a diagnostic and combustion check, identify any install issues (wrong venting, undersized gas, missing flush valves), and get you on an annual maintenance schedule. If the original installer cut corners, we document what we find and fix it properly.
    Are parts in stock locally?
    Most common Navien service parts (flame rods, ignition components, sensors, PC boards, pump assemblies) are available through local parts channels on the South Shore. We carry the fast-moving items on our trucks. For rarer parts we get next-day or two-day delivery.
    Local trust + next step

    Why South Shore homeowners choose Johnson Bros.

    Family-owned and local
    Serving Quincy, Abington, and the South Shore.
    Licensed and insured
    MA Master Plumber License PL #17034-M with insured work and professional standards.
    Clear service path
    We'll review your request and confirm the next available appointment.

    Need Navien service or diagnostics?

    Call if it's down or throwing a code so we can triage the visit. If you're setting up annual maintenance, book and we will put you on the schedule.

    Call About Navien ServiceBook Annual Maintenance

    Need help fast? Call for urgent plumbing issues. Booking online is best when you want the next open appointment without waiting on the phone.

    Areas we serve
    QuincyBraintreeWeymouthHinghamPlymouthMarshfieldScituateAbington

    Related services

    Navien Overview

    Main Navien specialty page.

    Navien Installation

    Installing a new Navien — proper gas, venting, commissioning.

    Navien Error Codes

    Complete guide to common Navien fault codes.

    Need Navien service or diagnostics?

    Call if it's down or throwing a code so we can triage the visit. If you're setting up annual maintenance, book and we will put you on the schedule.

    Call About Navien ServiceBook Annual Maintenance

    Call for urgent help now. Book online when you want the next available fit for your schedule.