14U heat exchanger stainless steel substitution

hmemerson

Hello all,
It has been a long time since I visited The Wall, in fact it was 2006. We had an Energy Kinetics EK-1 boiler system installed, and it has been nothing but a joy to own in terms of savings, functionality and service.

However.....we have soft water, and copper doesn't like soft water, so our flat plate heat exchanger (2nd one) is again showing signs of corrosion, which will lead to a pressure problem, etc.

We replaced all the copper pipe in our domestic system last year. Since moving into the house in 1995 I have, literally, repaired over 50 pin hole leaks, and it was exasperating. In talking to neighbors we've discovered many with the same issue. We did all the usual stuff regarding a possible errant neutral from the electric pole, having the grounds all tightened up, but nada......so now I want to replace the 14U copper heat exchanger with one made from stainless steel.

While I'm hoping to hear back from Energy Kinetics, I'd like to hear from the craftspeople here who know this stuff hands-on.

Thank you in advance for whatever knowledge you can share!

Best regards,
Howard Emerson
Huntington Station, NY

hot_rod

How soft are you running the water/ No need to taking it down to 0 or 1 gpg. Check the salt settings maybe.

All sorts of options for aggressive water plate heat exchangers. They build them for deionized water and aggressive fruit juice production for example. Different types of stainless are used based on the quality of the fluid, or water.

szwedj

@hmemercon, The plate heat exchangers we use are made of 316 stainless steel, the copper is used to braze the stainless plates together. As there are numerous things that can cause copper corrosion including salts from softeners as @hotrod mentioned, as well as low pH and acidic water. You may want to have someone who installs water treatment systems test your water and possibly make a recommendation on the best way to treat your water.

As an additional note, the plate heat exchangers we use now come with a thin glass like coating called Sealix. This coating is designed to significantly reduce fouling, scaling, and corrosion to minimize the risk of failure and maintenance costs in tap water systems.

hmemerson

hot_rod said:

How soft are you running the water/ No need to taking it down to 0 or 1 gpg. Check the salt settings maybe.

All sorts of options for aggressive water plate heat exchangers. They build them for deionized water and aggressive fruit juice production for example. Different types of stainless are used based on the quality of the fluid, or water.

Hi Bob,
Thank you for replying!

We don't use a water softener. Our water is straight from South Huntington Water on Long Island. The only thing we ever noticed was the morning that they started chlorinating over a decade ago, and it was a sad day. Prior to that the water was wonderfully wet and pretty pure......but we still had leaks before & after that started.

If you know how to 'read' these reports, here's the most recent I can find regarding our water analysis:

https://www.shwd.org/wordpress/wp-content/uploads/2023/04/SHWD_2022_ADWQR.pdf

It's interesting to note that since the boiler was installed, the 1/2" copper pipe that travels from the heat exchanger to the 40gallon storage tank developed a pin hole leak. I just left it alone and put a piece of rubber and a hose clamp on it. I was not going to bother the installer or my oil company for something like that. The installer, by the way, was Robert O'Brien of Technical Heating, and he used to post here quite frequently. Here's a couple of pictures showing the corrosion and pin hole leak with clamp.

hmemerson

szwedj said:

@hmemercon, The plate heat exchangers we use are made of 316 stainless steel, the copper is used to braze the stainless plates together. As there are numerous things that can cause copper corrosion including salts from softeners as @hotrod mentioned, as well as low pH and acidic water. You may want to have someone who installs water treatment systems test your water and possibly make a recommendation on the best way to treat your water.

As an additional note, the plate heat exchangers we use now come with a thin glass like coating called Sealix. This coating is designed to significantly reduce fouling, scaling, and corrosion to minimize the risk of failure and maintenance costs in tap water systems.

Hello Joe,
I assume by your signature that you are associated with Energy Kinetics? In the previous post reply to Bob I attached a picture of our current heat exchanger, which was installed in 2019. Here is a picture of the original one that we had removed after it was internally compromised:



I remember when we purchased the system that I got contacted by the late John Marran, and he sent me an EK jacket and some other swag. It was a really nice personal touch, but the amount of money we've saved over the years has been the best part of all. I think the installed price at the time was $6500, so it's already paid itself off!

Thank you for the reply and I hope there's something that can be done to increase the longevity of this otherwise wonderful system!

Best,
Howard Emerson

Roger

Thank you for you posts and kind words about my father and your energy savings, Howard!
As you noted, Joe is from Energy Kinetics and we feel that the Sealix heat exchanger will have a much longer service life in your unique application. It's extremely rare to see a copper brazed stainless steel heat exchanger leak, and to have multiple in one location is indicates you unfortunately have a very unique site specific condition. As you mentioned that you've replaced nearly all of the copper domestic piping, it's important to do the same near the boiler if you are unable to correct the source of the corrosion. The leak that is now patched makes me strongly believe there may be others that could occur, and having a leak with city water pressure can cause extensive damage so all exposed piping need to be corrected. I'd suggest installing a leak detection system that automatically shuts off your water supply giving your homes history. Even though you use the public water, I would also suggest that you have your water tested, preferably with an expert that can also test for stray current and other factors that can lead to aggressive corrosion. Please call us at 908 735-2066 or PM me if we can provide additional help.
Best,
Roger

hmemerson

Roger said:

Thank you for you posts and kind words about my father and your energy savings, Howard!
As you noted, Joe is from Energy Kinetics and we feel that the Sealix heat exchanger will have a much longer service life in your unique application. It's extremely rare to see a copper brazed stainless steel heat exchanger leak, and to have multiple in one location is indicates you unfortunately have a very unique site specific condition. As you mentioned that you've replaced nearly all of the copper domestic piping, it's important to do the same near the boiler if you are unable to correct the source of the corrosion. The leak that is now patched makes me strongly believe there may be others that could occur, and having a leak with city water pressure can cause extensive damage so all exposed piping need to be corrected. I'd suggest installing a leak detection system that automatically shuts off your water supply giving your homes history. Even though you use the public water, I would also suggest that you have your water tested, preferably with an expert that can also test for stray current and other factors that can lead to aggressive corrosion. Please call us at 908 735-2066 or PM me if we can provide additional help.
Best,
Roger

Hello Roger,
Thank you so much for your detailed reply!

For what it's worth: This house was the model for the area, built in 1952. The heating system was/still is based around a mono-flow T setup, and as far as I can tell, there has NEVER been a leak in the heating system copper. Obviously it's at a much lower working pressure than domestic water. Last time I checked the boiler pressure was set around 15-19lbs. Over the years, of course, it has been drained for boiler work or pipe repair, etc.

All of the plumbing done in the EK-1 install was with the Viega Pro-press, and there haven't been any issues with leaky joints or pin hole leaks in those pipes, with the only exception being the 14U to storage tank 1/2" bridge pipe. We've replaced several of the recessed convector radiators with Hide-a-Vectors or baseboard, and they, so far, have not acted up either.

I will contact you soon to arrange for some sort of evaluation. As I said in an earlier post we are NOT the only people in the area who've had to remove the copper domestic plumbing, so to have a definitive answer from an authority would be BIG NEWS!! This Old House never replied to my plea a couple of years ago, so bragging rights await:-)

Best regards,
Howard Emerson

szwedj

@hmemerson Yes I do work at Energy Kinetics and John was a great man who designed a great system.

I just wanted to point out that the plate heat exchangers you have are made from stainless steel and that the ones we have been using for about the three years now, do come with this Sealix coating for added protection which may on it's own extend the life of the plate.

I think typically this type of problem is more common on private wells then city water and treatment systems are commonly installed to correct it.

hmemerson

szwedj said:

@hmemerson Yes I do work at Energy Kinetics and John was a great man who designed a great system.

I just wanted to point out that the plate heat exchangers you have are made from stainless steel and that the ones we have been using for about the three years now, do come with this Sealix coating for added protection which may on it's own extend the life of the plate.

I think typically this type of problem is more common on private wells then city water and treatment systems are commonly installed to correct it.

Hi Joe,
I clearly was mistaking the visual copper on the edges for the plate material itself. My bad!

Now.....whether or not the one I had installed in 2019 has the Sealix coating I can't say. The newer one has the 10-0416 number minus the F designation. It was purchased from EK by Scalzo Oil in Huntington Station, NY as I could not purchase directly. Perhaps the purchase order number will give some information regarding whether or not it has the Sealix coating.....but I a water analysis would be a good idea no matter what!

Thanks again!

Howard Emerson

hot_rod

Would mounting* position have any effect? I know some brands suggest not mounting with ports down.

Roger

Thank you for your question and comments, @hot_rod . This is definitely a domestic water corrosion related issue. We have over 40 years of experience with plate heat exchanger applications and the position shown is correct and what we recommend for that model.
Roger

hot_rod

I would check the ph and chloride  levels in your water, stainless needs to be in a specific ranges. The hx manufacturers have a water spec typically

hmemerson

hot_rod said:

I would check the ph and chloride  levels in your water, stainless needs to be in a specific ranges. The hx manufacturers have a water spec typically

The chloride level range in the 2022 analysis was 3.4 - 33.0, and the PH was between 5.3-6.1.

HE

hot_rod

You need to test your water, occasionally for chloride level. That number is just a range they indicate, not an actual test number
You can buy a test kit and determine your exact number. It would be good to check oh, hardness, and chloride levels a few times a year, if you are having ongoing water issues

Then get the spec from the manufacturer  of the HX that you will be using.

Id still confirm the mounting position. I checked with 6 name brand hydronic/ water HX manufacturers. They all show that mounting position to be not acceptable. Armstrong shows vertical only mounting

it would be interesting to know what is different with the one you have? Maybe it is vented somehow. If not it could be trapping corrosive  gas from the water treatment chemicals in some of the plates. Worth asking the question, since you have had two fail?

Roger

Thank you, @hot_rod . I agree that the water needs to be tested and likely treated to prevent future copper tubing and other failures. From the photos and the background, we can see that the copper brazing is being attacked like the copper tubing; the stainless steel will be much more corrosion resistant. The original heat exchanger lasted from 2006 to 2019, and the water company started chlorinating. The flow rates through the heat exchanger on the domestic and hydronic sides will flush out any air, and the "fitting down" orientation also prevents entrained deposits from settling and building up in the heat exchanger - I'm sorry to see that other manufacturers miss these important points. We see fitting up as totally unacceptable.
Roger

hmemerson

Hello all,
When I originally posted in November, I was relatively certain that it would not be long until I saw water under the boiler.

Preemptively I had my oil company purchase a new 14U flat plate heat exchanger, and got a call from them 2 days ago to schedule the install, which would have been next Tuesday, March 5.....but I saw water under the boiler this morning, and they'll be here later this morning to replace the 14U.

Hopefully the new one with the glass coating will last longer.

I did make a point of speaking with the office at the water district, and we do have very soft water, so I'm reasonably certain that's the culprit, and the reason we replaced all the copper in the house. Many neighbors in the area have had the same pinhole leak problems with their copper pipe.

We also had the electric company check the feed from the pole for an errant neutral, and that was not an issue.

I'm going to chalk it up to being a wear & tear item, and be thankful that I've been working on a bathroom renovation in our home that has me standing at a tile saw directly next to the boiler.

As far as some sort of water treatment system goes, I really tried, but when phone calls & emails don't get
returned there's not much I can do.

I do want to thank Roger at EK for his help and counsel.

If there is some useful reason to send the bad exchanger somewhere for an autopsy, let me know where to send it.

Best regards,
Howard Emerson
Huntington Station, NY

Roger

You're welcome, Howard.
You may want to check the pH in that report as it is likely well below 7 (acidic) to have pin holes widely reported in copper tubing. Please keep in touch on the Sealix heat exchanger, if you do have any issue, I'd like it back for failure analysis.
It's disappointing that you are not hearing back from local water treatment companies, although I could see why they are very busy if that's a common issue with the water supply. Keep trying, even if you can't schedule anything for months out - you'll be much happier knowing that your home will not spring a spontaneous leak from a failed and corroded pipe (although considerable damage has likely already occurred).
Roger

hmemerson

Roger said:

You're welcome, Howard.
You may want to check the pH in that report as it is likely well below 7 (acidic) to have pin holes widely reported in copper tubing. Please keep in touch on the Sealix heat exchanger, if you do have any issue, I'd like it back for failure analysis.
It's disappointing that you are not hearing back from local water treatment companies, although I could see why they are very busy if that's a common issue with the water supply. Keep trying, even if you can't schedule anything for months out - you'll be much happier knowing that your home will not spring a spontaneous leak from a failed and corroded pipe (although considerable damage has likely already occurred).
Roger

Hi Roger,
The new 14U is installed already. So nice the way the system is set up.

It's not a matter of a water treatment company reply, but my contact with our EK installer who also knows about matters of water quality, etc. As much as I like him, I think he takes on too many projects, and just can't say 'No, I'm too busy, so I can't do it'.

We spoke once, I sent the link to the water analyses, and then crickets.

It has, though, given me the impetus to rid the entire house of copper. There's only a little bit of it left to be taken out, and it's in a dropped ceiling area, so not too much of a problem.

The little piece of 1/2" copper going from the 14U Domestic Water out to the hot water tank has a hose clamp covering a pin hole I found, actually. It is original to the install.

I will certainly keep an eye on the 14U!

Best,
Howard Emerson