Navien Tankless Water Heater Repair
- No hot water output
- Error codes on the display
- NaviLink app not connecting
- Flow sensor not detecting water
- Ignition won't engage
- Water leaking from the unit
- Scale buildup reducing performance
- Fluctuating water temperature
- Short cycling on and off
- Sudden spike in gas or energy bills
- Venting or air intake blockage
Our Happy Customers
Common Navien Tankless Water Heater Problems We Deal With
- No hot water output
- Error codes on the display
- Flow sensor not detecting water
- Ignition won't engage
- Water leaking from the unit
- Scale buildup reducing performance
- NaviLink not communicating
- Fluctuating water temperature
- Unit won't start
- Short cycling
- High gas or energy bills
- Venting or intake blockage
No Hot Water Output
When a Navien tankless water heater stops producing hot water, the cause is usually tied to a failed ignition module, an activated flow sensor fault, a blocked vent, a gas supply issue, or a control board that's no longer starting the burner sequence correctly. Navien's NPE and NCB series units often flag the issue with an error code on the display before the symptom becomes obvious, so an early inspection can save you from a bigger repair.
Our technicians work on the full Navien lineup, from NPE tankless water heaters to NCB and NFC combi-boiler units, and diagnose heating and hot water problems quickly. We'll get your Navien unit back to full performance as fast as possible.
Error Codes on the Display
Navien units show a specific error code on the front display for issues ranging from an ignition failure to a blocked exhaust vent, and misreading the code can lead to the wrong part being replaced. Common triggers include a flame rod fault, overheat lockout, water flow error, or a communication error between the PCB and remote controller.
Our technicians know how to pull and interpret Navien's error codes and trace them back to the actual failing component, so you're not paying for guesswork.
Flow Sensor Not Detecting Water
If your Navien unit won't fire up even with a faucet running, the flow sensor may not be registering water movement due to sediment buildup, a clogged inlet filter, low water pressure, or a failing sensor itself. Tankless units rely entirely on this sensor to know when to ignite.
We'll clean the inlet filter, check water pressure, and test the flow sensor to restore reliable hot water on demand.
Ignition Won't Engage
If your Navien unit won't ignite, common causes include a failed ignition module, a dirty or misaligned flame rod, a closed or restricted gas valve, or a blocked intake or exhaust vent. Venting issues are especially common on tankless units installed in tight mechanical closets.
We'll test the ignition system, gas supply, and venting first, since that's often the fastest and most affordable fix, and move on to deeper diagnostics only if needed.
Water Leaking from the Unit
Water around your Navien unit is typically caused by a failed pressure relief valve, a cracked heat exchanger, a leaking condensate line, or loose fittings on the water connections. Left unresolved, this can damage walls, flooring, and surrounding equipment.
Our technicians will locate the source of the leak, repair or replace the failed part, and confirm the unit is sealed and draining properly before we leave.
Scale Buildup Reducing Performance
Mineral scale buildup inside the heat exchanger is one of the most common issues on tankless units, especially in hard water areas without a water softener. Scale restricts water flow and heat transfer, leading to reduced hot water output, error codes, and eventually premature failure.
We'll descale the heat exchanger with a proper flush, check the water hardness, and recommend a maintenance schedule to keep your Navien unit running efficiently.
NaviLink Not Communicating
Navien's NaviLink app relies on a stable Wi-Fi connection and constant communication with the unit's control board, so a dropped connection, a firmware glitch, or a failed Wi-Fi module can prevent the app from showing accurate status or responding to remote commands.
We'll test the Wi-Fi module, check the connection to your network, and reset or reconfigure the system so it's communicating with your Navien unit the way it should.
Fluctuating Water Temperature
Sudden temperature swings, sometimes called a "cold water sandwich," happen when the unit can't keep up with quick changes in demand, when multiple fixtures draw hot water at once, or when the mixing valve or temperature sensor is malfunctioning. Undersized units for the household's hot water demand can also cause this.
We'll check the flow rate, sensors, and mixing valve, and confirm your Navien unit is sized correctly for your household's hot water needs.
Unit Won't Start
If your Navien unit won't power on at all, check first for a tripped breaker or blown fuse — but the deeper cause is often a failed transformer, a bad remote controller, a safety lockout that hasn't been reset, or a control board fault.
We run a full electrical and safety-circuit diagnostic on Navien equipment to find the actual cause and get your unit started again without unnecessary part swaps.
