Navien Heat Exchanger Problems

salmonhunter71

My 2nd set of Naviens are leaking at the heat exchangers & buffer tank. 1 is for domestic, & 1 is for domestic and space heating with a heating box. This is a new construction job.

I am re-posting this, last time I could not get back on to respond to the viewers. Thanks to those who looked.

Here is the situation. I cannot get Navien to give the tolerances of their heat exchangers. Does it exist? Rinnai List's the their tolerances on page 15 of the Condensing installation manual. ex: Chlorides up to 250mg/l. I tested & Navien tested my customers well water; both produced about 140mg/l max level. Navien won't replace the units because the chloride level is to high. But, I have talked to the area Rep. & the President of Navien America both won't provide a chart or description of what kind of water their Naviens will be warranted under.

Myself & the electrician have check for a short of some kind, but nothing was found.

What originally happened was the contractor placed the backwash for the water softener pipe above the well head which was 20' or less above the water level.

Navien replaced the units under good faith & the contractor moved the backwash line far away like 80-100'.

The second set of Naviens started leaking after 5-months of service.

We have tested the water for the second time  PH 7.2, Chloride 140mg/l, copper .250 mg/l, zinc .504 mg/l. Is their something I am missing and should be looking for?

 Today I am going to the customers house and going to look at the shower valves & take apart a couple of copper pipes both cold & hot to see if there is any corrosion beyond the water heaters. Thankfully the house is plumbed with PEX.

Any-help is appreciated

TonyS

Where are they leaking

Has the stainless corroded?

EJ hoffman

other chemicals?

Is the combustion air intake run to the outside picking up chemicals from the outside? or are there chemicals stored around these units?

CMadatMe

Chloride

Not sure what type of stainless is used in the Navien but that little Chloride friend may be a contributing culprit

salmonhunter71

Corrosion

The air intake is outside on the roof 1'-0"+  away from the exhaust.

The upper stainless heat-exchangers are showing white/green powder crusting up on the outside of the stainless. The condensate trap had about 3-tablespoons of rust colored deposit in it from the combustion chamber.

The units are installed in a basement mechanical closet with nothing else but a heating box and a sealed sewage ejector in the floor.

I did go back to the jobsite on Tuesday & pulled apart some shower valves, some copper pipes and all seemed normal; this was done to see if the water was destroying the plumbing. Thankfully all seemed to be normal so now homeowner & myself can be reassured his house plumbing is OK.

The chloride is in the treated water.

For the record, I have been in the Plumbing & Heating industry since 92.

This morning we pulled 1 of the units apart. It appears that Navien uses 3 different metal components in their units. Maybe somehow we have a low grade battery on our hands. The upper heat exchanger is stainless which has enough iron in it to draw a magnet to itself. The lower heat-exchanger cover is a nice looking aluminum, but inside that is the secondary heat exchanger which is made of a galvanized plate. So, with three dissimilar metals with a little chloride running through it being heated we seem to have found the perfect environment to destroy a Navien.

salmonhunter71

Testing

I took the heat-exchanger to a metal testing lab to see what it would take to check the contents of the metal. I know by using a magnet that I can pick it up off the ground. For sure the plate you see in the picture is galvanized, but what is the material that the water actually run's through is not 100% sure at the moment. I have suspicions, however I will keep this posted with the latest developments

Ironman

Really curious about this

Most primary heat ex. that are stainless are made of ferritic ss (409). It handles high temp much better than austenitic ss (304, 316). The austenitic is also much more susceptible to chlorides. The magnet sticking to the heat ex. would seem to indicate that it's ferritic and less susceptible to chlorides.



We've been installing the Navien for about 6 months and haven't had any issues like this yet. I'm curious as to what their response has been about this and what kind of support they've given you?



Please keep us posted as this progresses.

salmonhunter71

Water Test Report

So after the last post I thought I would look at the water report actually done by Navien in Korea. The cold treated sample had no manganese, 0.081 zinc, 0.154 copper mg/l. The heated sample which shows rust had .250 mg/l, .504 mg/l zinc, and .005 mg/l manganese. Are these found in stainless or galvanized metal?

The battle is brewing.

CMadatMe

Other Navien Post

That other post Supply House Rick posted has to be eating at you...Suggest you find another brand...Go Nortiz...

salmonhunter71

Check your Navien

OK. So, my metallurgist has not got back to me since Wednesday. The lower heat exchanger does seem to be a series 400 stainless/ferritic. A poor quality at best. The President of Navien has not contacted me for 3-days. He did ask for a copy of my original invoice, but what? I don't know what he is really going to do. At first Navien seemed interested. The fact is I am no closer to what Navien is going to do, than 2-mos. ago. I am starting to draw some conclusions.



Navien & other off shore stainless steel tankless manufactures tested their units on city water, not well water with a water softener using salt Na-Cl sodium chloride. The most frustrating thing about all of this is no-one seems to be an expert in their field. The water treatment people  say chloride should be flushed out during a backwash ( if the system is operating properly ), keywords should be; I call BS. The chloride levels are higher after the water has been treated. Again the chloride level is 1/2 of the EPA  level. I called Eternal Tankless Tech support & they said their stainless can handle any standard level of EPA approved water with its contents. Navien use to say that their stainless was invincible.



Here's the bad news folks I don't think some offshore tankless manufactures have a clue about the possibility of Chloride in well water. Case in point I had a buddy of mine check his Navien condensate trap, yes he is on a well with a salt water softener & there was alot of rust ( 1-year old, 14 to go ). I did not install it but I told him that this might be the beginning of something really big. I am assuming Korea is not a completely advanced country like the U.S. If you don't live in a city you are probably poorer than city-folk and the last thing you are going to buy is a water softener for your water. So yes this might be a new problem for Navien, but their service as of lately is terrible on my issue.

See, if you did not know when chloride is in the water it attaches itself to the chromium creating chromium chloride, it then dissolves into the water and exposes the iron allowing it to turn to rust.



On my situation the upper heat-exchanger was dripping on the lower causing it to rust and collect in the condensate trap.



So if anybody out there installed a Navien tankless water heater  on a well system that has a water softener using bags of salt, I would be curious if the condensate has rust in it, that would be your heat exchanger.



Still working on it trying to collect some ammo ( not literally yet ) and putting some weight on Navien to do something. Fact is they never warned anybody about chloride that I am aware of. 

Mark Eatherton

Chlorides are not good for machines OR humans...

We had a customer who was a prominent MD cardiologist. His recommendation was to yank the water softener out and live with the consequences of having hard water. He said the hardness was less detrimental to humans than the chlorides. In fact it can be advantageous as it pertains to dental hygiene. (Calcium beats tooth decay)



As a kid, growing up in a family plumbing business, I watched my dad's customers age over time. He remarked that almost every one of his male customers who had a sodium based water softener i had suffered some sort of cardiac condition from hardening of the arteries, to a complete blockage heart attack.



The good Doctor gave us a copy of a report that the AMA had generated warning people with propensities of arterial sclerosis, high blood pressure, etc to avoid washing, bathing and definitely drinking softened water. It seems that the salt will leach through your skin during showering/bathing and cause issues with YOUR pipes (arteries and veins).



The WQA hates me for bringing this issue to the surface, and they can make all the claims they want to, but it has been my experience over the last 36 years that magnetic water conditioners will provide lime scale accumulation protection for the water heaters in your life, and avoid the problems attached to chlorides, be they sodium or magnesium. The only time I have ever seen the magnetics not work is on a material called "Glass Water" which is prevalent in some parts of Texas and Oklahoma. And the manufacturers are aware of this limitation.



If it were me, I'd put in a whole house magnetic water conditioner, and get rid of the salt softener. I suspect that this is new territory for Navien as well, and am surprised that they haven't commented in more detail. But if legal action was even hinted at, they would be wise to read and not comment, but they still need to address the situation sooner rather than later...



ME

rlaggren

Some info on metals on the web

I'm not in SF right now where I have most of my bookmarks so I can't give you direct links. There are several well attended lists/forums where your issues of stainless and chlorides might be addressed by true experts.



I think that if you raised the question on



www.practicalmachinist.com    or    www.weldingweb.com



and asked for links you would quickly find leads to lots of info.





Best luck.   Rufus

HDE_2

Bad chlorides!

Chlorides are bad, seen it cause all major brands of stainless steel indirect water tanks to fail. On that note, I doubt eternal has anything better than the rest, especially at the water tube welds.

TonyS

Water conditioners

Mark and I have had this argument before about electronic water conditioners. Last time, I purchased one and bypassed my softner! Since then I have removed my softner completely. Mark is absolutely correct, they work very well. Not only has my Navien been functioning perfectly but the salt stains that were on my black bathroom group have disappeared. Before the conditioner, the fixtures... the toilet at the trap line most noticeable, had calcium stains, after the softner was installed, the calcium stains were replaced with salt build up, now with the electronic conditioner the stains are gone.

Having been a member of WQA I just didnt want to believe it.

So, like Mark said, ditch the softner and install an electronic conditioner.

HDE

Something was wrong

Tony,

Since sodium is a byproduct that rides along with the chlorides to regenerate the resin bed, if you had salt stains your softener was malfunctioning, salt setting was too high during regeneration of your cycles, mainly the fast rinse wasn't working or too short.



Full water test both raw and conditioned would have confirmed this.

TonyS

TDS unchanged

Water enters a aggregate filter first for mechanical filtration.. leaves clean with a PH of 5.6 to 6.0 and a hardness of 3. Then enters a reverse flow neutralizer with a 80/20 mix calcite and mag ox and leaves with a hardness of 10 and a 6.8 to 7 PH. Enters water softner and leaves soft and TDS unchanged.

HDE

There's your answer

Since adding sodium would register as an increase in TDS, it's not sodium

TonyS

Why would sodium

increase TDS ? What else would it be?

TonyS

increase in TDS

TDS should remain unchanged in ion exchange, any increase would be extra unrinsed salt.

HDE

That's exactly what I said

Me- "Since adding sodium would register as an increase in TDS, it's not sodium"

Perhaps its a fouled resin bed

salmonhunter71

Navien Report

I should have a report on the heat exchangers by this weekend from the Metallurgist, they were out of town at a refinery. My bad, all of this is testing my patience with the whole ordeal. I would really like to find a smoking gun.



I will hand it to Rinnai & Noritz, who both put the limitations on paper in writing, stating that their water heaters will be warrantied under EPA standards or the like regarding water quality. Instead of standing behind the statement ( poor water quality ) only to be defined on a case by case issue after the water heater is installed.

HDE

Limitations?

I was thinking after the first units failed I would have been looking for the reason versus allow the conditions to repeat the failures.

TonyS

Not sure what you mean

My water before the softener was 10 grains hard and it was dead soft after leaving the softener, but the TDS remained the same before and after. The softener worked fine, it did exactly what it was suppose to do, trade off calcium for sodium, ion for ion.

Softened water leaves sodium residue and the amount of residue is based on how many ions of calcium it replaced. The harder the water was originally the more sodium it will contained when softened. This is why only deionized water is used for the spot free rinse at a car wash.

salmonhunter71

Clarification

HD Employee, when the first unit failed (1) they were 1st. generation Naviens, (2)

Navien replaced units with hardly any questions so I figured they knew something I did not.  Like, potentially bad heat exchangers. (3) The conditions of the water was off the charts. And for the record one person in our shop installed a Navien in his own house on city water that started leaking through the heat exchanger, which was replaced. I truly thought it was a coincidence that both were happening at the same time. You know the routine, you deal with experts who really are not. They tell how it should work, not how it might when things are all out of sorts.





I had know idea before July about the different characteristics of stainless & the different series. My issue with Navien is that at the seminars they say that their heat-exchangers are virtually indestructible. But, nothing in writing.

Anyways, all this discussion is good. So, talking about water softeners. What is suppose to happen to the chloride after the sodium is laying in the resin bed? And if my chloride levels are going up after the water softener, where is that coming from? What is happening or not happening?

I typically have not been involved with water treatment until now. Till my equipment started failing. Today, I am going out to another job 1-year old, installed by someone else, rust in the condensate trap.



I am telling you out there this is not going to be an isolated incident.

TonyS

When a water softner exchanges ions

The chloride attaches to the calcium and becomes calcium chloride and the sodium remains in the bed as sodium bicarbonate. So what you see build up from the use of a softner is not actually sodium chloride but sodium bicarbonate. You shouldnt have any chlorides left in the water.

salmonhunter71

Chloride

Tony, you say I should not see any chloride levels rise in my water from the water softener. What if it was not functioning properly? What would have to happen to increase the chloride level. Because the chloride level is lower in the raw water than that of the treated. On Friday I was at three different Navien locations, all on wells with water softeners. Two had medium brown rust in the condensate trap, one had bright orange rust in the trap.



This is really disappointing. Any guess on how long those heat-exchangers will last. 15-years, I doubt it.  I am being pro-active on this. Each place I was at I took water samples to check for chloride. Next week I will be checking some city water Naviens to see if they also show signs of rust. These units are 2-years old & newer.



So HD Employee, I am taking it a step further for my customers and looking out for their best interest. When I get my water reports back I will compile some info and ask Navien what I am suppose to do since I have outbreak of rusting heat-exchangers.



 Before buying any new equipment I now know that I can not take a person or manufactures word at face value, there needs to be a legal document. Otherwise they can say what ever they want and change the warranty to fit their agenda.

seabee570

big problem

I posted before on this,I had a situation that happened in a commercial building where a large hot water storage tank lining was destroyed by using soft water.most hot water tank manufacturers do not want soft water being introduced into their tanks. 

HDE

Condensate trap

I'm not following why your judging brown water in the condensate trap, that's the combustion side. The condensate is the result of combustion which can't be related back to the chloride issue which is with the water inside the heat exchanger. The condensate is formed outside the secondary heat exchanger. However if there was a heat exchanger leak, there would be constant flow from the condensate line.



Btw I asked, the SS is # 436, meaning is ferritic, thus the magnet sticking. 436 is used for corrosion + heat resistance, along with flexibility for changing temps

TonyS

Something interesting

However the sodium (or potassium) ions released during conventional water softening are much more electrolytically active than the calcium or magnesium ions that they replace and galvanic corrosion would be expected to be substantially increased by water softening and not decreased[citation needed]. Read entire article.



 www.12stonesinc.com/index.php/articles/water_softeners/

salmonhunter71

Inside & Out

Yes, I am mentioning both the inside & outside of the heat exchanger. ( This is the scenario ) The upper heat-exchanger started pin-holing & dripping on the secondary causing corrosion which dripped and chunked off during condensing and washed down into the trap.



The reason I started this, was that the secondary heat exchanger looked terrible after 5-mos of service after taking it apart looking for a cause why the condensate had rust in it. The secondary looks suspicious. The primary heat-exchanger was the one that actually failed. It was dripping on the controls, also the buffer tank is leaking but I did not bother with it yet.



The heat exchanger is solid metal all the way through. My proof that they have inferior stainless is that the heat exchanger cant even handle the acidic condensation that it makes during its normal heating process, which obviously has nothing to do with my water. The fact is, if it rusts on the inside it will rust on the outside, making it a quick check by dropping the condensate into a bucket.



Now, here is a picture of the condensate water from a different Navien with no obvious corrosion on the primary heat-exchanger. There is no rust that I could see in the tap water, but you can see what is in the cap & bucket. The rust is from the secondary which can not be seen unless you dissect the water heater.



My first heat-exchangers are still at the lab undergoing the scope.

MikeG

Filling with soft water

Are there any issues of filling a closed system with soft water?  I have a Munchkin boiler which I initially filled with soft water.  I use potassium chloride and not salt but it is still a chloride.  I don't have any leaks so there isn't an issue of constant make up water, but I am in the process of adding a zone so some water will get added.  I'm also using an Amitrol indirect for DHW.  In operation a little over a year.  Thanks  Mike