Navien Tankless Error Code Troubleshooting

Like any other water heater, sometimes you may experience a problem with your Navien tankless water heater. When an issue arises, your Navien will likely display an error code on the LCD display on the front of the unit.

Need to hire a plumber?
Get a free estimate online
from top local home service pros in your area.

There are a large number of unique Navien error codes that help with troubleshooting the issue. Some problems can be solved with simply resetting the water heater unit (press the Reset button on the front panel) but other require more work.

Below you’ll find the most common error codes for a Navien tankless water heater along with a suggested fix. Often, you can complete simple fixes on your own with a few tools but for some more complex problems, you’ll need to contact a professional plumber who is familiar with Navien models or go straight to the manufacturer for support.

Have a different tankless water heater brand that needs troubleshooting?

Navien Tankless Water Heater Error Codes

Error Code E003
What it Means: Ignition failure in your tankless water heater.

How to Fix: Confirm the main gas supply valve is open.

Error Code E004
What it Means: False flame detection.

How to Fix: Confirm properly grounded electrical cord.

Error Code E012
What it Means: Flame loss.

How to Fix: Confirm properly grounded electrical cord. Inspect and clean intake air filter.

Error Code E016
What it Means: Overheated heat exchanger.

How to Fix: Turn off the water heater for 30 minutes and restart. Inspect and clean the filter in cold water inlet. Flush the heat exchanger.

Error Code E030
What it Means: Exhaust overheating. The unit will shut down when the temperature in the flue exceeds 149° Fahrenheit (65° Celcius).

How to Fix: Turn off the water heater for 30 minutes and restart. Inspect and clean the filter in cold water inlet. Flush the heat exchanger.

Error Code E046
What it Means: Abnormality in limit control.

How to Fix: Call technical support (800-519-8794).

Error Code E047
What it Means: Abnormality in exhaust thermostat.

How to Fix: Call technical support (800-519-8794).

Error Code E060
What it Means: Abnormality in dual venturi.

How to Fix: Call technical support (800-519-8794).

Error Code E109
What it Means: Abnormality in fan motor.

How to Fix: Inspect and clean the intake air filter.

Error Code E110
What it Means: Abnormality in air pressure.

How to Fix: Confirm there are no obstructions in the exhaust pipe. Inspect and clean intake air filter.

Error Code E407
What it Means: Thermistor open or short circuited (hot water outlet).

How to Fix: Call technical support (800-519-8794).

Error Code E421
What it Means: Thermistor open or short circuited (cold water inlet 1).

How to Fix: Call technical support (800-519-8794).

Error Code E432
What it Means: Thermistor open or short circuited (cold water inlet 2).

How to Fix: Call technical support (800-519-8794).

Error Code E434
What it Means: Abnormality in water adjustment valve.

How to Fix: Call technical support (800-519-8794).

Error Code E438
What it Means: Abnormality in circulation pump.

How to Fix: Confirm all water supply and return lines are open. Check direction of the internal 2-way valve.

Error Code E439
What it Means: Abnormality in flow sensor.

How to Fix: Call technical support (800-519-8794).

Error Code E441
What it Means: Thermistor open or short circuited (hot water inlet 2).

How to Fix: Call technical support (800-519-8794).

Error Code E445
What it Means: Abnormality in bypass mixing valve.

How to Fix: Call technical support (800-519-8794).

Error Code E515
What it Means: Abnormality in PCB.

How to Fix: Confirm proper grounding of electrical cord.

Error Code E517
What it Means: Abnormality in DIP switch setting.

How to Fix: Call technical support (800-519-8794).

Error Code E593
What it Means: Abnormality in front panel key.

How to Fix: Call technical support (800-519-8794).

Error Code E615
What it Means: Abnormality in input and memory.

How to Fix: Call technical support (800-519-8794).

Error Code E736
What it Means: Abnormality in cascade communication.

How to Fix: Call technical support (800-519-8794).

Error Code E740
What it Means: Abnormality in outdoor temperature sensor.

How to Fix: Call technical support (800-519-8794).

Error Code E760
What it Means: Flushing/service alarm.

Need to hire a plumber?
Get a free estimate online
from top local home service pros in your area.

How to Fix: Call technical support (800-519-8794).

Error Code E782
What it Means: Abnormality in main panel communication.

How to Fix: Call technical support (800-519-8794).

Error Code E785
What it Means: Abnormality in flow switch/sensor.

How to Fix: Call technical support (800-519-8794).

Related Posts:

Comments

  1. Since I’ve had it for a year and a half every so often no hot water will come out of the Faucets until I go outside to the heater and push the reset button and then it comes back on. I’ve had to do this on both models. The LP180s and the 240 models.

  2. Have Model NR-240 LP since 2012. Unit has gone into error 026 while I shaving (no other fixtures using ANY water and no other appliances using gas)! Has happened while people are showering. Happens when washing dishes in the sink. Every time = Error Code 026. Navien Tech Support suggested multiple causes: ‘insufficient gas supply’ (either not enough propane in supply tank or inadequate gas supply from the gas regulator), ‘water pressure insufficient’ to ‘inadequate air intake supply’. Had gas company on site and had Navien Tech on phone with him. All potential ’causes’ were dispelled… LP tank is never less than half full, water supply/pressure consistently adequate and stable, air intake is provided in a 1,200 plus cubic foot externally vented storage area… and using manometer (spelling?) gas company verified that the gas supply/pressure/flow was exactly as required by manufacturer. I even had the gas company install a gas regulator specificall for the Navien unit (separating it from my gas fireplace) but the problem persisted. I was keeping a log of the problem, but stopped out of frustration. Mostly because I was told, ‘Call when it happens.’ I did call a few times and read off the error code (was told to power off/on and did it – which is certainly not a resolution), another time Tech had me open the unit and read off an internal LED panel code (was then told to power off/on – again, not a resolution), another time was directed to change a few ‘dip’ switches… and finally, power the unit off and on (if this sound repetitious — it is!).
    I am awaiting the catastrophic failure of the heater and will replace it with a Rinnai. I have shared my story with every other homeowner as they are building their house (and have posted it on our housing development web page). I have a close friend on an Architectural Review Board for a housing development (6,000 plus home sites) and he recommends reading my “review” of the product to every person that is beginning to build. You can not even write to the Navien management to ask for assistance… there is no web site link for it.
    Completely disappointed in the performance of the device as well as the ‘support’ team behind it.

    • Wow, I’m sorry for your experience. I’ve only heard about error code 026 one other time (Navien has no information about it online or in their manuals as far as I know). If I recall correctly, their issue was electrical because their home was susceptible to power flickers and short outages from time to time. Not sure if it was resolved or if your issue is even similar.

  3. I have a navien 240a. Same issue. Every 1-2 months unit will not fire error code 003. Hit the reset switch and everything is fine. Not acceptable

  4. i have a navien nr-240a (ng) it is flashing a code of 038E and then 12.00
    on the remote it is flashing 38 E then a 012 at the bottom

  5. I have a navies tank less water heater model # nr210. I’m getting a 45 E error code and only heats for about 3 min before getting error message and stoops heating. Also drips water from the bottom port when plug is removed. Please advise

  6. Every so often the hot water will quit, I have to hit reset, if that does not help, I hit power button. Most times that will start the water, no code shows. But the unit is trying to fire, but with no water it will not really fire. What is the reason.?

    Unit is the npe180a residential use.

  7. My Navien NPE-180A stops working and shuts off all water through it. It will restart by pressing the on/off switch and will heat water and reopen the water flow; but will not stay on when demand stops. There is no error code. What should I try next?

    • That’s a tough one if there’s no error code showing. The flow sensor seems to be the culprit for a lot of issues on this model but again, it should have thrown an error code. I’d recommend calling Navien on this one.

  8. I’m having a temperature fluctuation while taking a shower. There is no other hot water being used. Has anyone had and fixed this problem.

      • Unit worked fine yesterday, had a power outage and today it’s error code 038. Restarted it 10 times and no luck. Nothing ovious, full gas, full pressure, grounded, screen clean. It’s 3 am and I give up. I’ll call plumber in morning.

    • I had a similar problem. Remembered i recently changed out tub/shower fixtures. No flow restrictions in them. So if valve open too much, demand is higher. Navien unable to keep up with volume to heat. Solution: Don’t open hot water valve to much. All good.

  9. I have navien 240 it’s 2:25am. And it’s too cool. The code present is 03 error. I did everything was recommended and is not working yet. Navien company have to come with a solution.

  10. We are getting the error code E438 . Our unit was unplugged for two months while we were away and as far as we know nothing was changed except for the unit being unplugged. We tried resetting it after we plugged it in but no luck. I am very leary about going into the internal and checking the directions of the valves but as far as I know no one had messed with the valves

  11. We had ours for 2.5 years. It’s a NCB – 240 e. It breaks down multiple times a day and we have spent almost $1000 on repairs to the same water flow sensor. It’s leaked water all over our floor, left us without heat and hot water for days. This is the worst product ever. I would stop anyone from buying one.

  12. My Navien Model: NPE-240A is throwing a E.594 Code! Cannot find this code anywhere! What does this mean and how do I fix it??

    • Hi Jennifer! If you are still experiencing issues with your unit we recommend that you call into our tech support at 1-800-519-8794 option 2 so that we can have our team diagnose the issue and provide a solution. Our tech support is available Mon-Fri from 8am – 9pm EST and Sat-Sun from 8am – 8pm EST. Thanks!

  13. I found the code and the “fix” but it’s not working:/ any ideas? E016 says turn off check filter then flush, filter is brand new, flush done by professional 3 days ago.. 1000$ bill coming my way. Would love to fix issue on my own…

  14. We have had our navien ncb 240 e for almost two years .on top the cost of installation we have had to have repair men out 5 times at least . It is repeatedly breaking down and the cost is out of our pocket. This product is too expensive to own . We are considering changing back to central heat and water heater. I would not recommend Navien at all.

  15. NPE 210S displaying E.012 Hot water stops after running for 20 mins. Replaced Flame Rod Assembly every year for the last 3 yrs. Never find debris in the air intake filter. Electric cord is grounded.Temp set @ 117°. Any reason for this be happening?

    • This seems to be a common problem with the 210S. Seems the Dual Venturi gas/air mixer is often the culprit as its motor fails not allowing the heater to get to stage 2.

Leave a Comment