E010 on Navien with solution and report on my problems over 4 years

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QueBall

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Ok, So I have a 4.5 year old Navien NR-210a condensing tankless heater. (Late 2010)
I more or less did the entire install myself with the help of a few skilled friends either on site or on the phone to give advice.

While I'm not an installer or service tech working on these things all day every day I do talk to one frequently and he has passed on some of his general observations as well as what I have directly experienced with my own system.

I have had a few glitches with mine during the time it has been installed but nothing too bad. My friend who services these tells me the older the unit the more glitches you get. The newer ones are way better than the older units. He says they used to get a fair number of calls for tanks that were installed by other companies that had constant ongoing problems that could be traced back to poor installs. The usual big culprit is not enough gas supply when switching out an old heater. I know in my house it was a major undertaking to get the 3/4" line installed, we had to go through a finished wall to reach the meter but we did a home run right back to the meter and I have never had an issue with gas supply. I know if I just tied into the existing 3/4 line feeding the furnace, fireplace, BBQ, and garage heater it wouldn't have worked very well.

So, the older units like mine definitely have a few glitches to watch out for. The prior CR series are the ones with the most serious troubles. The newer NPE are supposed to be very good, and can even tolerate retrofit installs that the old one would have failed without new gas lines and bigger vents (Though I would still want a full sized gas supply so the unit doesn't have to restrict water flow to match gas supply)

First, a sure fire point of failure on older NR units. The water flow sensor will fail on yours if it had not been upgraded to the newer design with stainless steel internals. The old plastic impeller model will fail if it hasn't already. It's very easy to remove this and inspect it. This part is right near the front on the cold water inlet just before it goes into the heat exchanger with some simple push fit clips holding it in. Take it off and look inside, if you see plastic, get a new one. Navien will likely send you a free replacement if you are still under 5 years. If not buy one and keep it on hand, it's not a very expensive part. When it fails the impeller either gets encrusted with deposits or simply wears out and wobbles and gets stuck. If you remove it and give it a shake and blow into it you can often get it spinning again so the heater works for another hour or another day. But it's a relatively simple part to replace.

So next thing I just had happen is Error number 10 or E010 or 10E 010E etc (for the search engines).
This probably indicates a problem with your combustion air supply. Not enough fresh air, or some blockage in the air vents.

Usually that just meant that air filter on the input air is clogged. So if you get that error you just take off the cover and in the extreme top left of the machine you unscrew the mesh filter and clean it out and start it up again and things are fine. You know this is your problem if you can run the machine with the cover removed (so it draws air from the room instead of outside). You might also have a blockage outside, sucked in some leaves, or trash blocking the air intake. I even had a mouse try and build a nest in the pipe when the outdoor pipe cover fell off. he left in a hurry the next time the unit was used but his debris was still there blocking the air.
In this case it didn't make a difference.

The next thing to check is the cleanout on the bottom for the siphon (white cap near the gas input). This can get clogged up with debris and soot from the burner. If the debris blocks the condensate drain then it will cause this same issue. I guess it creates some kind of back pressure when the condensate drain is blocked.

Last up is the air pressure sensor (APS). This is a black device mounted on the top of the burner with two small hoses coming out of it and it's about the size of a hockey puck. The service manual will tell you that you can check the voltages coming from this device with a volt meter. It gets 5v supply on red and black wires and returns a signal of 0.3v at idle up to about 4.5v when the fan is running at full speed on the white and black wires. I did this test and it showed my APS was reporting what seemed to be a good voltage. Unfortunately it was still bad. The next test is what the Navien support asked me to do. Remove the APS from it's mounting (2 screws holding it in place). Remove the top hose and gently blow into it. You are blowing into a sealed chamber so you should not get any air leakage. If there is air leaking out of the sides or a crack then the APS needs to be replaced. When I blow into my old one I can feel air leaking out of the seams around the sides of the unit. The replacement had no such leak. I tried to temporarily seal the leak but it didn't help, I guess the readings from the sensor didn't match up with the fan speeds which is why the unit wouldn't work.

In my case the unit would try to start up. The fan would start running at moderate speed and then switch to full speed and run continuously for almost a minute before it shutdown with the e010 code. There was no attempt to light the burner. Just before shutting it down when I first noticed it wasn't working it was cycling between purging and attempting to light the burner. I got an ignition error code I think e012 for that event, but it was the same root cause, just a bit different sequence since the machine had just failed and it had not been shut off yet.

So bingo, that was my problem in this case, bad APS.

To summarize my experience, I have certainly had some moderate glitches that have brought the machine to a stop over the 4 years.
-I had the mouse make a nest in the exhaust air line causing E010 errors
-Every spring when to poplar tree and dandelion seeds are like a snowstorm outside my air filter gets clogged frequently causing the E010 error. (I started leaving the cover off during this time of year as it's annoying to clean it every day usually right when you are about to step into the shower)
-I had a problem with the air purge vent on the top of the recirculation pump get clogged with hard water deposits.
-I broke an O ring on that same air purge vent after removing it for cleaning on a subsequent scheduled maintenance (de-scaling)
-Of course de-scaling the unit on a regular basis is important. But my first small pump broke, so I bought a more heavy duty one now.
-I had a faulty water flow sensor
-I had a faulty air pressure sensor

I would suggest if you have a unit of the same age you keep a few spare parts on hand.
I have now started keeping the following supplies
-An O ring kit of various sizes. I would tend to do the descaling on a weekend when the suppliers are closed and I have found out that is exactly the time when you are most likely to break an o ring or develop a leak due to a failing ring. pn: 30009933A
-replacement water flow sensor pn: 30010537A
-replacement APS sensor pn: 30000663A (Probably do not need to keep this part on hand, after you replaced it)
-replacement air purge vent if you have the older recirculation pump. (Newer style has a red cap on the purge valve and hopefully doesn't get hard water deposits collecting in the valve to cause leaks) pn: 30006830A
 

Dana

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"I know in my house it was a major undertaking to get the 3/4" line installed, we had to go through a finished wall to reach the meter but we did a home run right back to the meter and I have never had an issue with gas supply"

So, how is it that you got away with 3/4" gas line for a 180,0000 BTU/hr burner?

gas-natural-piping.jpg


I must be an awfully short run, with VERY few ells to hit the ~15 equivalent-foot limit! Either that, or you cheated the spec (by a lot), and are lucky the thing is working?

Most installations would need 1" or 1.25" gas line (plumbed as a home run) for a modulating burner that size to operate completely without issues. You're probably never/rarely running the thing past 100K.
 

BadgerBoilerMN

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Though fascinating and accurate this information is of little use to the OP since the new Navien NPE series is so much improved it bares little resemblance to the old NR-210a in operation or maintenance issues. It is in fact a rare turnaround for any manufacturer to support older equipment while improving the new so dramatically. You have to give them credit.
 

QueBall

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Thank you for your concern about gas sizing, yes it is short enough.. Gas has never been an issue with my setup, can run it with all fixtures opened up. Sizing was verified to be good.

Also the NR is still sold though maybe not promoted anymore, so they continue to support it plus the 5 year warranty is likely only starting to expire on the earliest units sold. I think they hit the market in 2010, maybe late 2009.

Seems like some of the part redesigns like the water flow sensor were important enough to carry back to the previous series. So if you buy a replacement part today it includes the improvements made in the newer models. It's not just a direct replacement on the previous part with the less reliable design.
 

matty123

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Word! Thanks Queball for your thread. I had an E10 with 027 on a Navien 240, the air pressure sensor was the culprit. simply blowing into the top air inlet test did make a "click" as if to indicate the bladder was making the seal... at first i thought it was ok but applying constant pressure did show a very slight air leak. On further inspection, the air pressure sensor is closed with 4 flanges which fatigue and one corner had a microfracture which went over the area of the o-ring. Simply applying hand pressure was enough to get a totally different and very positive seal with the test. I used a 1/16 drill bit to make 2 small holes on either side of the flange, put 2 tiny wood screws in and then used a soldering iron to melt/weld the plastic.... bingo, great seal and will work as a temp until the new 30 dollar air sensor comes in.
 

Stone859

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Thanks so much for this thread!!

I know this is an older thread but I have a Navien 240, installed in 2010. The unit has worked well for the years and no problems until about six months ago, and we kept getting the E 10 code. The code would stop the unit, usually when you need to take a shower the most, but the water heater kept working once the code was cleared. When it would run it would pulse loudly and kick-in and out. I couldn't figure out how to fix it and called in a repair person. The repair person worked on it for about two hours, called Navien and still couldn't find the problem...I replaced the spark ignitor, but no luck. Two weeks later the repair person came back out and still couldn't find what was wrong, even though the company was on the phone telling him to check, and that, and just about everything...we checked gas pressure and various voltages on various things...still no go. The Navien person finally said "you need to replace the mother board"...I didn't agree. We kept the water heater like it was, sort of working. Then it went out completely...wouldn't start and the E10 would not clear. I spent a couple of hours and found this thread, and I suspected a air presure problem, and then found this thread about the APS. I removed the APS, blew in the hose, and found a leak! It has a small hair line crack...very hard to see. I ordered a new part, but was able to glue the old one (I'll install the new one when it comes in) and fix it, it runs like new!!

Thanks again for posting about the APS, you helped we when all the "experts" were unable to!!
 
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David Alpha

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Navien 240, 10E error. Changed APS, cleaned filter, checked pipes, no dice. Drove me crazy. So I opened up the fan, only 3 screws, and there is a one way trap door, right after where the fan connects to the burner assembly. I gently pushed it open a few times, and wow, unit started to work right away, error code gone! I was going crazy. So one last hail Mary, take the three screws off the fan, pop off the fan assembly, and the trap door assembly might have gotten stuck.
 

Dana

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Navien 240, 10E error. Changed APS, cleaned filter, checked pipes, no dice. Drove me crazy. So I opened up the fan, only 3 screws, and there is a one way trap door, right after where the fan connects to the burner assembly. I gently pushed it open a few times, and wow, unit started to work right away, error code gone! I was going crazy. So one last hail Mary, take the three screws off the fan, pop off the fan assembly, and the trap door assembly might have gotten stuck.


When you had the cover open, did you happen to see any oily residue, discoloration on the main control board, or rust around the rubbery gasket on the exhaust port?

If yes, the lifecycle of that unit is probably limited. Those are all symptoms of exhaust leaks internal to the cabinet in the water-tube heat exchanger type Navien models (boilers, combi-boilers, and water heaters alike), and even warranty-replacement heat exchangers are leaking at the gasket between the burn chamber & heat exchanger (right above the sight glass & igniter). Hopefully yours is of a vintage with better quality control &/or design details/materials and doesn't have either of those issues.

lau59l0qzanv.jpg

^Residue on bottom side of the heat exchanger assembly. That is not a water leak or water condensation!^


From a safety point of view as long as the gasket around the main cabinet cover is in good shape the exhaust won't be leaking into the house, since the cabinet itself is at negative pressure when operating (it's sucking gases in, not blowing out), whereas the burner & heat exchanger are at positive pressure relative to the air in the cabinet.

When exhaust is leaking internally it becomes mixed with the combustion air, leading to higher moisture content & lower oxygen content in the combustion air than the system is designed for, and it will shorten the product life as well as lowering the net efficiency. This is why intake air and exhaust venting ports outside the building envelope need to be adequately spaced to keep the warranty valid (and how Navien can duck at least some of the warranty claims even when the main problem is leakage & cross contamination inside the cabinet.)
 

EddieRiv

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My Navien CH240 Combi Boiler was giving me a 10E(010E) error code, it would start after a while but with a knocking & swishing sound in the heat exchanger, i did what everybody else does, i went online, i read all the posts from other people with my boiler, did everything they suggested, i checked almost everything, cleaned all the filters, checked every radiator for trapped air, checked all the pipes & hoses 100 times, after 5 hours i was ready to throw in the towel & call the pros, but there was 1 hose i didn't thoroughly inspect, "the big hose under the heat exchanger"... I removed the hose clamp on the bottom & twisted it loose from the heat exchanger & it was completely clogged with rusted pieces, i stuck my pinky in the heat exchanger to loosen it but it was packed solid so i stuck a wire hanger in & all of it came gushing down, there was at least a pint or more of condensate trapped in the heat exchanger. Needless to say my boiler is working perfectly again.
 
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