It was a Tuesday morning in January. A homeowner in Merrick walked downstairs to find her Navien boiler flashing E003 and the house getting colder by the minute. She called two companies. Neither one had worked on a Navien before. The third call was to us.
We were there in two hours. Fixed it same day.
That’s not an unusual story. Since so many Nassau County homeowners switched from oil to gas over the past decade, Navien boilers have become one of the most common heating systems on Long Island. And because they’re sophisticated condensing units — not your basic old boiler — they need someone who actually knows them.
That’s us. AJ Services is a family-owned plumbing and heating company in Bellmore. We’ve been working on Navien systems across Nassau County for years, and we know these units inside and out.
Navien condensing combi boiler installation for heating and hot water
Navien builds some of the most efficient heating equipment on the market. The NCB combi-boilers, NHB boilers, and NPE tankless units are popular across Long Island for good reason — they run clean, they’re compact, and they cut heating bills for homeowners who made the switch from oil.
But when something goes wrong, they speak in error codes. And if your technician doesn’t know what those codes mean, you end up with a cold house and a technician guessing.
Here are the most common Navien error codes we see on Long Island service calls:
Short cycling, inconsistent hot water, low pressure lockouts, and condensate drain freezing are also common on Long Island Navien installs — especially in houses where the original installation wasn’t quite right.
Not every boiler repair company knows Navien. That matters more than most people realize.
Navien systems use a different diagnostic approach than older atmospheric boilers. They have multiple sensors, a modulating gas valve, a condensate trap, and a sealed combustion system. Getting a repair wrong — or misreading a fault code — can mean an unnecessary part replacement, or worse, a misdiagnosed issue that comes back three weeks later.
AJ Services has the hands-on experience with Navien units to get it right the first time. We diagnose accurately, we explain what we found, and we fix the actual problem — not just clear the code and hope for the best.
Nassau County’s water is harder than most areas. Mineral scale builds inside Navien heat exchangers faster than homeowners expect. If your system is losing efficiency or throwing E110, scale is often the culprit. Annual descaling adds years to your unit’s life.
Navien recommends annual service to maintain warranty coverage. A lot of homeowners skip it. Then they wonder why their system started having problems at year four or five.
On Long Island, annual Navien maintenance is more important than the manual suggests. Salt air, humidity, and hard water all take a toll that’s faster here than in drier, inland climates. We service Navien units all across Nassau County every fall and catch problems before they become January emergencies.
Our Navien maintenance visit includes:
We’re AJ Services. We’re based in Bellmore, and we’ve been servicing heating systems in Nassau County for over 20 years. Ben, the owner, is personally involved. When you call us, you’re talking to the people who actually do the work — not a dispatcher routing your call to a subcontractor.
Our reviews tell the story better than we can. 4.9 stars across more than 200 Long Island homeowners. People mention that we show up when we say we will, explain everything clearly, and don’t upsell them on things they don’t need. That’s the way we were raised to do business.
We work on Navien systems throughout Nassau County — Bellmore, Wantagh, Merrick, Baldwin, Freeport, Oceanside, Lynbrook, Valley Stream, Rockville Centre, Massapequa, Garden City, Levittown, and beyond.
What does a Navien E003 error mean?
E003 is an ignition failure code. It usually means the unit tried to fire and couldn’t establish a flame. Common causes are a dirty flame sensor, a gas pressure issue, or a faulty igniter. It’s one of the most common Navien calls we get in Nassau County and it’s usually a straightforward repair.
Why does my Navien keep shutting off?
Short cycling — where the unit fires up and shuts off repeatedly — is often caused by a scale buildup in the heat exchanger, a blocked condensate drain, or a sensor fault. It can also happen if the unit was oversized for the home. We’ll diagnose the actual cause rather than just reset the unit.
How much does Navien boiler repair cost in Nassau County?
It depends on what’s wrong. A sensor cleaning or condensate drain clearing might be a service call plus a small parts cost. A heat exchanger issue is a bigger job. We’ll give you a clear price before we start anything.
Is my Navien still under warranty?
Navien offers warranties ranging from 5 to 15 years depending on the model and component. Warranty coverage typically requires proof of annual maintenance. We can help you check your registration and service history.
AJ Services serves all of Nassau County & Suffolk County for Navien boiler repair and maintenance. Call (516) 807-8700 — we’re available 24/7 for heating emergencies.
Our emergency phone line is 24/7.
Appointments are scheduled from 8-5 Monday through Friday, except for emergencies
Phone: 516-807-8700
Address: 2448 Charles Ct, Bellmore, NY 11710