Navien Tankless Error Codes Troubleshooting

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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.

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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.

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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).

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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.

    Reply
  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.

    Reply
    • 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.

      Reply
    • If it is the gas supply Rinnai is not the answer. They consume gas at a larger rate and require a larger gasline. Navien is the best on lower gas volume. You may need to have the gas pressure set by a professional using a manometer. Then set the combustion with a Combustion Analyzer. Which is the measure of unburnt gas. I am certified and a licenced Plumber for 37 years I service and work on Navien, Rinnai, Aosmith. Lochinvar Tankless waterheaters. I have a Navien tankless water heater in my house. No problems If properly set up.

      Reply
  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

    Reply
    • Have you had any luck resolving this? I just bought the Navian 240 a and in the past week I’ve had to reset several times. Navian Told me I need to call while the plumber is here… I had a plumber check with a man to meet her today and he said it’s exactly as specified.

      Reply
  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

    Reply
  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

    Reply
  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.

    Reply
  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?

    Reply
    • 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.

      Reply
      • Navien will not help the consumer. They require a technician to be present in order to offer trouble shooting advise.

        Reply
    • Did you get an answer to your question? I have the same issue with 210A. It kicks on periodically without any water demand at all as well as when using only cold water

      Reply
      • You have an internal buffer tank on the “A” models (this is a good thing, and prevents cold spurts of water when cycling taps on/off). The unit is running to heat the internal buffer tank water. While this is happening, you can press the INFO button and press + and – to scroll through GPM and inlet/outlet water temps. This will show you that you have 0 GPM and its heating the water in the buffer tank, so when you want hot water, its ready for you. Nice feature to have.

        Reply
  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.

    Reply
      • 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.

        Reply
    • 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.

      Reply
  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.

    Reply
  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

    Reply
  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.

    Reply
  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??

    Reply
    • 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!

      Reply
  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…

    Reply
  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.

    Reply
  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?

    Reply
    • 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.

      Reply
  16. Hello. We have a Navien-180A that was installed in May. The unit regularly gives us a E003 code and we are typically in a rush to have a shower so unplug the unit and then reset and it works but it is a major pain to keep going to the basement to reset it. Our service plumber (Boonstra in Canada) not find anything wrong with the unit when they came to look at it. Any advice? We have had to reset it 6 times in September and the first half of October

    Reply
    • Hi Aaron! We are sorry to hear that you have experienced issues with your unit. We recommend that your licensed plumber 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. We need to be able to confirm the problem and resolution with a trained professional in order to resolve issues in the field.

      Your licensed plumber or contractor can download the “VisualSupport-RemoteCall” App in Google Play or Apple store. Once they download it, they can call 800-519-8794 option 2 and inform the technician that they have the Visual Support App.

      Our tech will provide him with a code to put into the app so that we can view your installation from his phone (like Skype) and we can go through the installation and check for common installation mistakes. When things aren’t installed correctly, it can cause premature failures in your unit. We can also go through troubleshooting and diagnostics at that time to determine what, if anything, is wrong with the unit.

      Thank you,

      Reply
      • Just want to say thank you to the Navien rep for the responses here. I’m in no way notifying them of reader comments so the fact they are monitoring this page for issues shows they care about customer service.

        For all readers considering a Navien (or any other brand), keep in mind that like any other appliance, water heaters can have rare issues. It’s much more likely you’ll read about negative experiences online vs those that are completely satisfied with their water heater.

        Reply
  17. HI, I have a Navien NR210A that has stopped working with error code 10E and 027 under it.
    I have cleaned the air filter and and the plug in the bottom. it started working once and stopped again now all I hear is gurgling sound in the heater and the fan but it goes to error mode after a minute or 2 with no ignition. Please advise.

    Reply
    • 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!

      Reply
  18. For all issues with Navien units, 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.

    Reply
    • For all issues with Navien units, 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.

      Reply
  19. I bought the 180 combination model and in 8 months, we spend more than $800. Error 001 keeps coming and hot water not working. After resetting hot water stops in two minutes, cannot take showers or use bathroom faucets. Regret buying this NAVEIN UNIT.

    Reply
  20. I have recently installed a NCB-240e, and I am getting and error code of e784. I am unable to find this error code listed anywhere in the literature.
    If anyone knows of what it is, please let me know.

    Reply
  21. I have a npe240s. About a year ago the unit shut off the water. No water would come out of the hot faucet and there were no error codes flashing. I unplugged the unit for a minute and when I plugged it back in you could hear it open up internally. It has happened again twice in the last two weeks. Any ideas on what is going on? I am a licensed plumber.

    Reply
  22. my customer has a navienNCB 240 (NG) unit has been running since 2017 and has had no issues .in the last couple of days it has been coming up with error code E109 – air intake filter cleaned – system reset – system runs for a few hours then sure down error code E109 displayed . this set of events continued multiple times – I attended customers residence – preformed an annual system overhaul recleaned all filters and flushed systems (domestic and hydronic heater sides) – restarted system and it ran 10 minutes then error code E109 showed up system shutdown.
    reset system and it runs for 12 hrs and error code E109 showed up again.
    filter is clean and dry no restrictions?
    any answers ?

    Reply
    • For all issues with Navien units, 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.

      Reply
    • Check your combustion fan motor. It sounds like something is going wrong with it. It may be the motor or something with the impeller. Good luck

      Reply
  23. Been hung up on by the call center 6 times now. Customer has a npn-199u that’s throwing code 773. Any help would be awesome

    Reply
    • Hi Cody, thanks for reaching out to us. We are very sorry to hear that you are experiencing issues connecting with us. Our Technical Support team is working as quickly as possible to resolve issues given the current circumstances. Please send us your contact number along with the unit serial number so that our Tech Support can reach out to you shortly. Thank you for your patience and understanding!

      Reply
  24. installed navien 180 combo and have spent 1,300 on repairs so far n now have another problem. hot water works intermittently .i shut boiler off than on n p21.8 shows up .a second later 591 than u-21 finally 2011. nothing w a e in front of it.possible its the 3 way motorized valve. HeLp thanks bob

    Reply
  25. Re: Navien support will only talk to technician.

    These are gas appliances. In my jurisdiction it is an offence for an uncertified person to install or perform maintenance on a gas appliance.

    Whether this is the reason Navien has for their policy I do not know. But I suspect liability issues lie at the root of their reasoning.

    Reply
  26. I am getting E038 code which apparently is to do with the circulation pump. I notice quite a few people have reported this code. Will replacing the circulation pump fix the problem and if so where can I get it from and how much does it cost?

    Reply

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