Cleaning Heat Exchanger

Our 8 KW Onan generator would run hot (over 225 degrees F) when trying to use 2 air cond units as well as battery charger, hot water heater, fridge and inverter charger. Eventually it would shut down. After checking all possible sources of restricted water flow, I concluded the heat exchanger needed cleaning. I's a b**ch to get to so I decided to try "Barnacle Buster."

I purchased the concentrate and diluted it per the directions. I then closed the raw water intake strainer seacock and ran the genset while pouring the solution into the top of the sea strainer. After introducing enough to fill the system, I shut down the genset and let things sit for 2 hours.

I then opened the seacock, and started the genset. The water coming out of the exhaust was dark brown at first and then cleared up. I can now run the genset with 3 AC units turned on plus all of the other items mentioned and the temp gauge sits right at 178 degrees. Now I will attempt the same process with the main engines.

BTW, I think the mods/admins should consider a thread category where members can report successes and failures with products they use/try. I think that would be most informative. Forgive me if it already exists and I just can't find it.

Howard

I'm very interested to learn other accounts from boat owners who have used "Barnacle Buster" for cleaning out heat exchange systems while they remain in place. Any ill effect on the metal parts inside the system... or on the hose insides or the thermostat?

Howard's account in post #1 sounds really good! I like to KISS as much as possible.

Interesting report thank you, I remember seeing something similar, but they said you had to circulate (reverse) it through the system, did the instructions say you can just fill and let sit? Out of curiosity could you share the cost?

The thermostat is within the antifreeze side of the cooling circuit so would be unaffected. I remember seeing hoses are unaffected as well, but zincs needed to be removed.

Art said:

I'm very interested to learn other accounts from boat owners who have used "Barnacle Buster" for cleaning out heat exchange systems while they remain in place. Any ill effect on the metal parts inside the system... or on the hose insides or the thermostat?

Howard's account in post #1 sounds really good! I like to KISS as much as possible.

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I called the manufacturer to ask if it could be done in this manner and they said it was fone. Told me that it was fine for all the system components including hoses. I purchased from Defender.com Search Results: barnacle buster

Hope this helps. Howard

Great, and thanks for the link, that's actually pretty good price given it makes 5 gallons.

hmason said:

I called the manufacturer to ask if it could be done in this manner and they said it was fone. Told me that it was fine for all the system components including hoses. I purchased from Defender.com Search Results: barnacle buster

Hope this helps. Howard

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By the way, you do not need to remove the zincs. However, you must replace them with new when you finish. I think that's the easier way. Howard

This is a timely thread. I'm planning on cleaning my heat exchangers after layup this fall. Thanks for the info.

Ken

While cleaning the heat exchanger is a great idea...so is pressure checking it.

If you have the capability and it's worth the effort...good!

A call to a local radiator shop for an estimate to boil, test and repaint may be worth the trouble.

Way more than doing it yourself...but all in all maybe not so bad if your time is worth something more than mine is...

Marlinmike said:

The thermostat is within the antifreeze side of the cooling circuit so would be unaffected. I remember seeing hoses are unaffected as well, but zincs needed to be removed.

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Thanks Mike - Re thermostat location - Soon as I think cooling "thermostat" comes to mind... Guess I had a brain freeze! lol

Does it tear the zinc's up pretty bad?

Howard - What was the situation with your heat exchanger pencil zincs?

Hi Howard - Mighty glad you posted Barnacle Buster info! Thanks!!

I've looked on net and was unable to locate link to Barnacle Buster office.

You have ph # to Barnacle Buster HQ. I'd like to speak with a tech there regarding using their product on boats in freshwater and for applications on other equipment.

Cheers! - Art

No discussion of descaling products for heat exchangers would be complete without mentioning Rydlyme.

Rydlyme is an HCL and organic salt solution (8%-10%) product, and has a safe (2.8) PH level. It is biodegradable and safe around skin and eyes. It is approved for use on USCG and EPA vessels.

Barnacle Buster is Phosphoric Acid-based (85%) product, and has a very low (1.0) PH level. It is biodegradable and generally safe around skin and eyes, some light irritation possible with prolonged exposure. It is not approved for use on USCG and EPA vessels.

I have used both products on marine diesels and air conditioning systems and both work very well. My preference is Rydlyme because it is readily available in my area. If I could not find it, I would not hesitate to use Barnacle Buster.

Larry
M/V Boomarang

I can definitely see the utility if it is hard to remove the HX. I know the stuff works great on AC systems too. However, the reason I choose to remove the Hx from the engines and have a shop do it is I also want it inspected completely cleaned and leak tested. I learned this expensive lesson the hard way on my generator.

LarryM said:

No discussion of descaling products for heat exchangers would be complete without mentioning Rydlyme.

Rydlyme is an HCL and organic salt solution (8%-10%) product, and has a safe (2.8) PH level. It is biodegradable and safe around skin and eyes. It is approved for use on USCG and EPA vessels.

Barnacle Buster is Phosphoric Acid-based (85%) product, and has a very low (1.0) PH level. It is biodegradable and generally safe around skin and eyes, some light irritation possible with prolonged exposure. It is not approved for use on USCG and EPA vessels.

I have used both products on marine diesels and air conditioning systems and both work very well. My preference is Rydlyme because it is readily available in my area. If I could not find it, I would not hesitate to use Barnacle Buster.

Larry
M/V Boomarang

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I spoke with a tech at Rydlyme. He said best to remove zinc first and install new after flushing. Not actually necessary... however, he mentioned: Rydlyme will devour the zinc and in so doing some of the solution's cleaning effectiveness on other items in the heat exchanger will be somewhat diminished.

http://www.apexengineeringproducts.com/products/rydlymedescaler/

Art,

That's the same advice I received from Rydlyme too.

Barnacle Buster's instructions state "NOTE: Magnesium/Zinc anodes will need to be removed before you start flushing or replaced after flushing is complete."

I always reverse the flow mid-flush on both engines and air conditioning coils. My flush hoses have garden hose couplers in them so it is easy to reverse the direction.

Larry
M/V Boomarang

This is a topic near and dear to my heart. First let me say that I am a retired chemical engineer who early in his career worked for a contractor who chemically cleaned industrial heat exchangers, boilers, etc. We mostly used inhibited HCl (hydrochloric or muriatic acid) but sometimes phosphoric acid and sometimes an organic acid. So, let's go from there.

Most trawler forum members don't have sea water intercooled engines, but some of us do. Do not do this without first removing, disassembling, cleaning- mechanical or chemical, lubing, reassembling and pressure testing the air cooler. If you have a leak (and some do) in the air cooler you will dump acid into your engine's air intake- not a good thing.

Also obviously if you have any reason to believe any of the heat exchangers are leaking, don't do this. I had pressure tested my coolant system beforehand so I knew that the main heat exchanger was ok. There are sometimes also a lube oil exchanger and a transmission oil exchanger in the system. Any unexplained rise or fall in the oil levels should tip you off that you may have a leak. If so remove and test first.

The heat exchangers in our engines use either a copper alloy or cupronickel (much better) for the tubes. The end caps are bronze or cast iron. These metals don't corrode much during cleaning, but use one of the commercial products made for this purpose: Barnacle Buster, Rydlyme, etc. will work fine. Hopefully they have a chemical inhibiter that will significantly reduce metal corrosion.

Do not believe whatever the previous poster said about HCl being safe- BS. It will destroy your eyes. Do not use swimming pool HCl. It isn't safe and probably isn't inhibited. The commercial products whether they have HCL in them or not will seriously harm your eyes if you get it in them. Wear goggles and have a garden hose handy to flush with. If you are doing this by yourself leave the garden hose running and know how to get to it with your eyes shut.

The OP described a fill, soak and flush method that works well. But a better way is to rig up a temporary pump (an old bilge pump works great) and circulate the cleaning solution through the heat exchangers back to a bucket from the raw water injection hose. I did this with my intercooled Yanmar engine (after doing the work described above) and it worked great. One of the benefits is that you can start the engine for a few minutes every hour while the solution is circulating and let the engine heat up the cleaning solution. The rate of scale removal (and metal corrosion) doubles with every ten degrees temperature rise. So circulating at 120 deg F will do much more than letting it sit at ambient. Also circulation brings fresh acid to the scale continuously.

I believe that you should circulate in the same direction as the raw water goes. That way you know that the heat exchanger tubes are full with no air pocket. It wouldn't hurt to reverse the flow at the end, but do most of your circulating forward.

In my previous life we circulated for four hours at 140 deg F. When I did mine I circulated (on and off. I had a pretty high capacity bilge pump so I didn't want to run it continuously) for 3 hours at 120 deg. The solution turned black within ten minutes.

Do remove the zincs and replace them afterwards. Otherwise you are ruining good zincs and using up some of your acid.

Flush with fresh water by dumping the bucket, filling with fresh water and circulating again for a few minutes. Do this 3-4 times then hook up the permanent hoses and run the engine for 10-15 minutes.

But if you know that you have lost zincs or impeller vanes or you are suspicious that some of the heat exchanger tubes are plugged, first remove the end cap, pull out all of the old zincs/vanes and rod the tubes with a brazing or gun cleaning rod. If a tube is plugged, acid won't do much for it.

David

Good advice thanks all.

In preparation for our trip, I bought new heat exchangers and now I'll have spares for the rest of my life.

The old exchangers were at least 15 years old.

I was surprised when I opened the main engine one that the tubes were in really good shape, but the screen in front of the tubes had a lot of organic matter, mostly twigs, that covered almost half of the sfc area.

I was further surprised after changing them all that the engine ran a few degrees hotter.

I suppose Lehmans like the twigs.

djmarchand said:

"Do not believe whatever the previous poster said about HCl being safe- BS. It will destroy your eyes."

David

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David,

I'm sure you are absolutely correct about HCl being unsafe. I was referring to Rydlyme, not pure HCl, and then, only when used as directed by the manufacturer. I should have stated that more clearly. It was not my intention to mislead anyone into thinking otherwise.

I was initially referring to a comparison I had found some time ago, when I was researching descaling products.

Then, from Rydlyme's FAQ page the first question which talks about safety on skin is:

Q: If RYDLYME contains HCl (hydrochloric acid), how can it be safe on my skin?
A: Though the active ingredient is HCl, there is less than 10% of the acid, and it’s only one element of the overall formula. Couple this with the special way it’s blended, and you have a nice balance of safety, biodegradability and effectiveness. That’s what makes RYDLYME so unique and why similar products fall short.

And finally, from the MSDS:


H

Art,
Try this link: Barnacle Buster

You can find the contact information there too.

Howard

LarryM said:

No discussion of descaling products for heat exchangers would be complete without mentioning Rydlyme.

Rydlyme is an HCL and organic salt solution (8%-10%) product, and has a safe (2.8) PH level. It is biodegradable and safe around skin and eyes. It is approved for use on USCG and EPA vessels.

Barnacle Buster is Phosphoric Acid-based (85%) product, and has a very low (1.0) PH level. It is biodegradable and generally safe around skin and eyes, some light irritation possible with prolonged exposure. It is not approved for use on USCG and EPA vessels.

I have used both products on marine diesels and air conditioning systems and both work very well. My preference is Rydlyme because it is readily available in my area. If I could not find it, I would not hesitate to use Barnacle Buster.

Larry
M/V Boomarang

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There's a third product, AC and Engine flush from Triton Marine Products.

Marine Enine Flush

Described as a "green" product. Says used by USN and USCG.

I haven't used it to flush our engines, but we did use it to flush our AC systems, essentially the same procedure as Howard describes: fill, let it sit, flush, get on with life. Worked well, although we also coincidentally took the opportunity to do some back flushing from the discharge outlets -- since we happened to be up against a full length floating finger pier at about the same time.

Also, FWIW, one of our marina neighbors had their genset's heat exchanger off while doing some other work, and decided they needed to to descale while they were at it. They borrowed a bottle of CLR, and said that worked very well.

-Chris

Larry:

I realize that you were not trying to be misleading. But statements like this leave me cold:

SHOULD NOT BE CONSIDERED HAZARDOUS WHEN USED AS DIRECTED.

And neither is a .357 Magnum, nitroglycerine, or a nuke hazardous if used as directed. Well, maybe not the latter ;-).

Use sensible precautions when using any of these acid cleaning products: goggles, rubber gloves (although it isn't going to eat up your skin, but you might be allergic) and keep a fresh water hose handy.

David

I was always a Penray man myself:

Cooling System Products | PenrayPenray

Cleaning my heat exchangers

I took the heat exchanger off of my genset, a 3kw Onan, and put the exchanger in the toilet, poured drain cleaner into it, and then flushed the drain cleaner with fresh water and flushed the toilet. Worked like a charm.

ranger42c said:

They borrowed a bottle of CLR, and said that worked very well.

-Chris

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Akin to someone asking to "borrow" a ciggie... back in the day! Girls were famous for that phrase!!

FYI: of the 3 heat exchangers in my engine room, all of them had at least half the tubes comkpletely blocked. I am not sure how well these products would effectively clean the clogged tubes. The only way to really find out is to pull the HX afterwards, which of course defeats the purpose of using it.

djmarchand said:

Larry:

I realize that you were not trying to be misleading. But statements like this leave me cold:

SHOULD NOT BE CONSIDERED HAZARDOUS WHEN USED AS DIRECTED.

And neither is a .357 Magnum, nitroglycerine, or a nuke hazardous if used as directed. Well, maybe not the latter ;-).

Use sensible precautions when using any of these acid cleaning products: goggles, rubber gloves (although it isn't going to eat up your skin, but you might be allergic) and keep a fresh water hose handy.

David

Click to expand...

David,

Thanks for your comments. You would crack up if you could see me when I use 'dangerous' chemicals. Just short of a hazmat suit and with a hose and my phone close by. If working alone, I even rehearse the procedure in my head to minimize and chance of fumbles, spills or splashes in the face!

Larry
M/V Boomarang

LarryM said:

David,

Thanks for your comments. You would crack up if you could see me when I use 'dangerous' chemicals. Just short of a hazmat suit and with a hose and my phone close by. If working alone, I even rehearse the procedure in my head to minimize and chance of fumbles, spills or splashes in the face!

Larry
M/V Boomarang

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Sounds like a logical approach and we should all be so careful angel:), but yes, I'd like to see a video of that.

I've always used White vinegar.
It's cheap, safe to use - doesn't matter if you spill some in the bilge - and cleans HEs as well as any other product. Just leave it in for a few days and then, open the water inlet and run the motor. Non toxic and environmentally OK.

Bendit said:

I've always used White vinegar.
It's cheap, safe to use - doesn't matter if you spill some in the bilge - and cleans HEs as well as any other product. Just leave it in for a few days and then, open the water inlet and run the motor. Non toxic and environmentally OK.

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Bendit

That sounds really good for ease of use and environmental protection.

Have you seen before and after inside the HE for visual proof that white vinegar really worked well?

Also, what effect on pencil zinc does white vinegar pose? With other cleaners mentioned pencil zinc was to either be removed prior to cleaning and replaced thereafter (recommended by manufacturers). Or it would get eaten up by cleaner (reducing cleaner's overall capabilities) and replaced thereafter.

Thanks, Art

Fellas, this conversation is over my head. Would someone tell me what zincs, you are talking about? The only ones I have in my minds eye are the one's on the rudder, shaft, & hull, all below the water line.