Navien Tankless Water Heater Repair
24/7 Emergency Repair Service Across Long Island
Schedule ServiceFast, Expert Navien Repair When You Need It Most
When your Navien tankless water heater stops working, you need a team that knows these systems inside and out. At All Island Comfort, our certified technicians specialize exclusively in Navien tankless water heaters, giving us the deep expertise to diagnose and fix problems faster than general plumbers.
We repair every Navien residential model sold in the United States, including the NPE-A2 Series, NPE-S2 Series, NHW-AI Series, and NHW-AE Series. Whether you have a simple error code or a complex heat exchanger issue, we carry the parts and knowledge to get your hot water back.
Navien Error Codes We Diagnose & Fix
Your Navien unit communicates problems through error codes on its display panel. Here are the most common codes our technicians resolve for Long Island homeowners.
Ignition Failure
The unit attempts to ignite but fails. Common causes include a faulty igniter, dirty flame rod, closed gas valve, or insufficient gas pressure. Often requires igniter or flame rod replacement.
False Flame Detection
The unit detects flame signal when there should be none. Typically caused by a faulty flame sensor, ground wire issue, circuit board problem, or a leak in the heat exchanger.
Flame Loss
The burner ignites but the flame goes out during operation. Check gas pressure (3.5" WC for natural gas, 11" WC for LP), intake air filter, ground wire, and heat exchanger wiring.
Heat Exchanger Overheating
Caused by mineral scale buildup (calcification) restricting water flow through the heat exchanger. Requires descaling with a vinegar flush. Left untreated, it can lead to pinhole leaks.
Overheating
The heat exchanger temperature has exceeded safe limits. May require cleaning the inlet strainer, flushing the heat exchanger, or verifying proper water flow through the unit.
Low Water Pressure
Water pressure has dropped below the minimum operating threshold. Check for closed valves, kinked supply lines, or low municipal water pressure. System resets once pressure stabilizes.
Air Flow Problem
An airflow sensor has detected insufficient combustion air. Could be a vent blockage (birds' nests, debris, ice), a faulty APS sensor, or incorrect venting configuration.
Exhaust Overheat
Flue gas temperature has exceeded the safe limit (230°F for more than 10 seconds). Usually caused by exhaust vent blockage, improper venting, or a failing exhaust thermistor.
Fan Motor Failure
The fan motor is not operating properly. May require cleaning of the fan assembly, checking the wiring connections, or replacing the fan motor entirely.
Outlet Thermistor Error
The hot water outlet temperature sensor is reading an open or short circuit. Typically requires replacement of the outlet thermistor and checking the wiring harness.
Maintenance Service Alarm
Your Navien is due for its routine maintenance flush. This alarm triggers based on runtime hours. We recommend annual descaling to clear mineral buildup and maintain efficiency.
Abnormal Water Flow
The flow sensor has detected an irregular water flow rate. Often caused by a failing flow sensor, clogged inlet filter, or partially closed water valve. Flow sensor replacement resolves most cases.
Don't see your error code? No problem. Our technicians can diagnose and repair all Navien error codes. Contact us or call (631) 591-2289 for immediate help.
Common Navien Repairs We Perform
Igniter & Flame Rod Replacement
The igniter creates the spark and the flame rod confirms the burner is lit. When either component fails, your Navien won't fire. We carry OEM igniters and flame rods for all Navien models and can replace them during a single service visit.
Heat Exchanger Descaling
Long Island's hard water causes mineral scale to build up inside the heat exchanger over time, restricting flow and causing E016 overheating errors. Our technicians perform a 45-minute vinegar flush followed by a 10-minute freshwater rinse to restore full performance.
Flow Sensor Replacement
The flow sensor tells the unit when to fire by detecting water flow through the system. A failing sensor can cause the unit to not ignite, produce lukewarm water, or cycle on and off unexpectedly. We stock OEM flow sensors and can complete the replacement in under an hour.
Control Board Replacement
The PCB (printed circuit board) is the brain of your Navien unit, managing ignition, temperature regulation, and safety shutdowns. When the board fails, it can trigger random error codes or cause the unit to shut on and off without explanation. We diagnose board-level failures and replace with genuine Navien PCBs.
Gas Valve & Pressure Adjustment
If your Navien is receiving incorrect gas pressure (standard is 3.5" WC for natural gas, 11" WC for LP), it can cause ignition failure, weak flame, or complete shutdown. We test gas pressure at the unit, adjust the regulator, and verify proper combustion.
Venting & Exhaust Repair
Navien condensing units (NPE-A2, NPE-S2) use PVC venting, while non-condensing models (NHW-AI, NHW-AE) require stainless steel. We inspect for blockages, correct improper venting configurations, and repair or replace damaged vent pipes to prevent E027 and E030 errors.
Thermistor Replacement
Navien units use multiple thermistors (inlet, outlet, and heat exchanger) to monitor temperatures throughout the system. When a thermistor fails, it sends incorrect readings that can trigger E407 errors or cause inconsistent water temperatures.
Condensate Neutralizer Service
Condensing Navien models produce acidic condensate that must be neutralized before it enters your drain. We service, refill, and replace condensate neutralizers to protect your plumbing and keep your unit compliant with local codes.
Navien Models We Repair
We service the complete Navien residential tankless water heater lineup. Click any model below to learn more about it.
NPE-A2 Series
CondensingPremium model with ComfortFlow built-in recirculation pump and 0.5-gallon buffer tank. Up to 199,000 BTU and 11.2 GPM. Industry-leading 0.96 UEF efficiency rating.
View NPE-A2 Details →NPE-S2 Series
CondensingStandard condensing model without built-in recirculation. Up to 199,000 BTU and 11.2 GPM. Ideal for homes that don't need instant hot water at every fixture.
View NPE-S2 Details →NHW-AI Series
Non-CondensingIndoor non-condensing model designed for easy installation. Stainless steel venting required. Budget-friendly option for homes that need reliable on-demand hot water.
View NHW-AI Details →NHW-AE Series
Non-CondensingOutdoor non-condensing model with weather-resistant enclosure. No venting required. Perfect for Long Island homes with limited interior installation space.
View NHW-AE Details →Our Repair Process
From your first call to problem solved, here's what to expect when you schedule a Navien repair with All Island Comfort.
Call or Schedule Online
Call us at (631) 591-2289 any time, day or night, or schedule online. Describe your issue or error code and we'll dispatch the right technician.
Pre-Arrival Call
Your technician calls before arriving so you know exactly when to expect them. No waiting around for a vague 4-hour window.
Diagnose & Quote
We perform a thorough diagnostic of your Navien unit, identify the root cause, and provide clear, upfront pricing before any work begins. No surprises.
Repair & Test
We complete the repair using genuine Navien parts, then run a full system test to verify proper operation, water temperature, flow rate, and combustion safety.
Navien Not Working? We're On It.
Our certified technicians are available 24 hours a day, 7 days a week across all of Long Island. Call now for same-day Navien repair, or schedule at a time that works for you. Don't forget to check our coupons page for current specials, and ask about flexible financing options.
Have questions? Check our FAQ page for answers about Navien repairs, maintenance, and more.