Heat exchangers

[Yannis]

Does anyone know if I pour vinegar into the raw water intake while the engine idles, and make sure that it stays inside the circuit for a few days, if this will dissolve the scale deposits in the system?
I'm trying to figure out an economical way to clean the heat exchangers without having to remove them and go through this costly enterprise!

[Carl]

I'm not sure, but your boat will smell like a salad for awhile.



Over here many have gone using a product called "Barnacle Buster". I believe it removes scale, rust, growth, line etc. With this stuff you make a closed loop and pump (recirculate) the product through the system for a couple hours, flush n go.


Supposed to be safe for motor and cooling system, biodegradable etc...But have that checked and don't take my word for it.

Vinegar is an acid, granted a weak one, but I may have heard Yanmar blocks are finicky about the coolants used. I'd verify with a Yanmar dealer over I may have heard and the like.

I have never used Barnacle Buster to say for sure, but a few friends say it made a difference. Maybe because it took most of the day and cost a hundred bucks.

[Yannis]

Carl,

The Yanmar pink cooling liquid is not affected; I'm talking about the raw water which circulates from the intake to the exhaust.
So instead of raw water, replace it temporarily with vinegar. Now, I'm not too sure how this can be done but if someone has done it I would like to know if it works.
And no, I will not have the engine idle for more time than what's needed for my vinegar quantity to be sucked in and then let it sit in there for a day or two and then go and flush it clean with water from the hose.
If the engine was warm when the vinegar got in, then it should start decomposing that scale deposits right away. It should doesn't mean it would though...

[S Ritzert]

I use CLR to clean calcium deposits in the cooling system. I do remove them, and dunk them in a bucket full of CLR though.

[Carl]

Right raw water, its not going through the block. I'm not sure what I was thinking.

Take what I said about the barnacle buster and it recirculates through the raw water side.

[Tony Meola]

Yannis

If you can find barnacle buster, you can do it without creating a closed circulating system. They claim you can suck it up into the engine, shut down and let it sit for about 8 hours.

I know a guy who does one side at a time while running his engines while out of the water for about 45 minutes. He puts a 30-gallon garbage can under one side of his exhaust. He has a sump pump in the bucket with a hose to a 5-gallon bucket on his deck. A hose runs from that bucket to his Strainer basket, or it can go to the water pump whatever is easier.

He puts the mix of barnacle buster and water in the 5-gallon bucket. Starts his engines and as the mix comes out the exhaust into the garbage can the sump pump pushes back up into the 5-gallon bucket. 45 minutes later he shuts down and rinses the engine out and moves to the other side.

He performs this operation every 3 years.

https://www.trac-online.com/products/de ... cle-buster
https://www.trac-online.com/application ... ns_R01.pdf

[Yannis]

If the CLR or any other barnacle buster can sit in there for hours, I don't see vinegar posing a problem. After all vinegar is much less caustic than any barnacle buster.
On the other hand, there is no barnacle issue here, just calcium deposits.

Now if I manage to get this vinegar into the system without having to organize all this plot with buckets, pumps etc, this will be a formidable task, albeit that it does indeed remove the calcium deposits...

[Carl]

After all vinegar is much less caustic than any barnacle buster.

I would think so, vinegar is an acid. Bases are caustic.

On the other hand, there is no barnacle issue here, just calcium deposits.

I do believe vinegar is a good way to dissolve calcium deposits...a quick check it also seems bases will do the same. Seems like my days back in Chemistry class where on a test I could guess:

How to dissolve Calcium Deposits:

A- Use Acid
B- Use Base
C- Use either
D- All of the above

I didn't get they why then, still don't get it now.

Anyway, I'd check with Yanmar dealer before trying. Mainly as I agree with you and that should scare you...lol.

[Ironworker]

I have used CLR numerous times in outboards. While it works it takes time. (I've also used in in coffee pots and dishwashers, so I use the same mix rate in the outboards).

If you're using a recirculating system the water gets hot and looses its cooling effectiveness. So you have to shut down the engine and let the water cool for an hour or so then fire up the engine until the water gets hot again.

Frankly, I think at the end of the day just removing the heat exchanger, cleaning and reinstalling would be the best procedure. One of the benefits is getting stuff relubed so that when you do get a problem you don't have to replace these heat exchangers. There is a video on Youtube about how to do this. Just be careful punching out the core.

BTW, I have a fresh water flush plumbed into my intakes which I hope will minimize my scale issues.

[Tony Meola]

Yannis

I use Vinegar to descale my Cobi Boiler for my house. I pump it through the system for about an hour. Not sure if it pulls out scale since I haven't seen any, but I will say it is pretty dirty when I am done. I have to follow up with a freshwater rinse.

Household vinegar varies from 3% acidic to 6% acidic depending on the brand. I found one at Walmart that was 6% and that is what I use for the Boiler.

Luckily on my Cummins, I can remove both end plats on the heat exchanger, and I found that a wooden dowel fits perfectly into the individual tubes and that is what I use to rod them out. That is ok to do but, pulling them off does allow you to do a more thorough job. You can flush it out better once you are done rodding them out.

Plus, when you pull them off you can paint them to make them look new again.

[Yannis]

Carl, Rick, Tony,

There is a 4 liter vinegar jug sold in supermarkets at 6% acidity, that I use as is in the washing machine prior to leaving for the summer vacation.
It keeps the machine clean of scale, or so i think, because I can't open it to verify.
I also use it in my espresso machine and there I see the water come out cloudy, which means it works.
The water has to be over 60C to do the job, a temperature that I regulate in the washing machine and it is definitely above 60 in the coffee machine.

So, I would think that if I run the engine for a while till it reaches this temperature, and then use the fresh water flush tap that I also have mounted on the water intake, if I manage to make this vinegar flow in with gravity (via some hose and funnel I assume) it will substitute the water into the system while the engine is still hot - a prerequisite for the vinegar to have its optimal effect- and let it sit there for a few hours, it should do the job.

I know that taking the exchangers out and cleaning them properly is the best, but I would like to try the vinegar method to see if that works too, while saving a few hundred euros at the same time. We do not have barnacles which would pause another more serious problem, just scale deposit.
The difficulty lies in managing to make the vinegar enter into the engine AND stopping the engine BEFORE it exhausts the vinegar out, so I need to have someone out by the exhaust to tell me when it starts smelling of vinegar so as to kill the engine in time.
Now that I think of it, I will also need a third person to kill the engine from the flybridge, while I pour the vinegar into the engine.
How does all this sound?

[Carl]

Could be done the way we winterize our motors here, well at least I do.

Stick the raw water pickup hose into a pail, fill pail with substance of your choice...I usually go with a non toxic pink antifreeze, but a nice 6% vinegar would be nice too. Start motor and wait till you see pink...or as you said smell vinegar...but a couple drop of food dye could offer a change of color.

As your looking to keep vinegar in the system and keep it full, I'd consider pulling the hose going to elbow (dump) high after motor is shut, so it system does not drain. The pump side has flexible impeller which will stop fluid from flowing back.

Could also route that elbow(dump) hose to the bucket to allow it to recirculate a bit.

[Yannis]

You mean to say that instead of holding the jug high above the engine and let gravity do the rest, I could fill a bucket with the vinegar and drop the hose in it - the other end attached to the intake flush tap? Does the engine suck by itself without the need of gravity?
I assume I should turn the primary raw water intake (through hull) shut, so that the vinegar doesn't drip down to the ground instead?

[Carl]

I was thinking of pulling the hose from seacock to pump and sticking that into a pail. But you should be able to shut seacock, fill with vinegar, attach hose to your Flush Tap with fee end into a pail. The pump will suck the liquid from pail...but a garden hose will be restrictive so keep rpm's low, also if the hose has a restriction...such as hose bends (kinks) free end suck the pail or something in pail, a garden hose will collapse. Its why raw water hose has the steel reinforcement to keep from collapsing.

[Yannis]

At idle the garden hose without reinforcement doesn’t collapse.

I wouldnt touch on the main seacock hose, that is remove it from through hull and stick it into the pail, I will need a monkey to go down there and undo the ring screw and then, as we all know, I will not be able to put it back together without leaks, at least without considerable effort and luck...

What I’m still confused with is, do I need a pump in this vinegar circuit to send the vinegar into the motor or does the motor pull/suck the liquid by itself?

[Carl]

The motor will suck up the liquid if presented before the raw water pump. AKA - seacock strainer with fresh waster hose barb attached going into pail with seacock closed and no leaks.


Or you plumb in after the raw water pump. Then you push water with gravity… tall hose n funnel or pump it.

[Yannis]

Perfect!

Here’s the plan:

Start the engines with water provision through the flush tap, as usual.
Let it get hot to over 60C.
Turn engine off and remove water source.
Connect the 4 liter vinegar jug with a hose, after I shut the seacock.
Restart the engine till vinegar is sucked.
Turn engine off and let it sit till it cools
Flush engine with fresh water.

I hope 8 liters per side will suffice. People will think that I run a restaurant at the supermarket, seeing me buying 16 liters of vinegar!

[Amberjack]

BTW, I have a fresh water flush plumbed into my intakes which I hope will minimize my scale issues.

Rick, I don’t know if this will reduce scale. In my experience working with boilers most scale is deposited during extreme temperature change I.e. ambient to boiling, in our case when the engines are running. But those fittings would make it very conventional to circulate 6% white wine vinegar a couple times a year to dissolve scale buildup.

Tony, you won’t see the scale when you flush your water tank. It is dissolved by the vinegar and comes out in solution. Interestingly 90% of scale is particulate based so it will be different colors depending. If you have acidic water and copper pipes your scale will be green and when you dissolve it and flush it out the water in your bucket will be green. Ditto reddish and if you have old iron pipes. The dirty water in your bucket could be dissolved scale which nucleated on turbid water or just sediment you flushed out.

[Tony Meola]

Yannis

If you suck the water through the hose, or even poor it through the hose, you need to close the seacock on the intake hose otherwise it will suck water from the outside and dilute the vinegar too much.

I would use 6 gallons or 23 liters of vinegar. That will ensure the engine is full of vinegar and it has started to run out the exhaust.

My friend needs 6 gallons of antifreeze on his 28 with yanmars when he winterizes the boat.

Doug

Interesting that you don't see any sediment. So then since it comes out on the dark side, looks dirty it's working. The Combi unit does not contain any iron in its components. I believe the boiler section is Stainless.

[Yannis]

Tony, the boat is on the hard so there is no water suction from the seacock.
I will turn the intake shut, so that the vinegar doesn't drain under the boat.

I agree with the antifreeze quantity, however here we are talking about the raw water circuit, not the antifreeze closed circuit.
I have no idea how much vinegar this will take, I purchased 16 liters for both engines. I will start with the one engine and if it takes more than 8 liters I will have to buy some more for the other engine.
I'm leaving on a mountain excursion for a week, so all this will take place after this...

[Carl]

My first year with the diesels sitting in boat not hooked up I winterized them even though they were supposedly drained running for the motor survey.
Wow, that was alot of words to say nothing...

Anyway, the raw water circuit used very little antifreeze. I disconnected the hose from raw water pump, held high, poured in the antifreeze till if came out the elbow mixer. maybe 2-3 gallons till it came out. I remember being kind of nervous with only so little antifreeze in the raw water side. I cracked a few hoses and pink came out. So I knew I was good...but still

With exhaust hooked up to mufflers its a good 5-6 gallons till I see pink.

Guess I could have saved alot of words and just said the exhaust holds alot of fluid.

[Amberjack]

Doug

Interesting that you don't see any sediment. So then since it comes out on the dark side, looks dirty it's working. The Combi unit does not contain any iron in its components. I believe the boiler section is Stainless.

Something is working since you’re flushing dirty water out but you could just be flushing dirt sediment collected in the trap-most likely that. My Navien has a drain specifically for sediment. But it could also be dirt particulates that bonded with dissolved mineral and then bonded with your heat coil to create dirty scale. If I can remember back to my 23 years gazing at the insides of espresso machines most domestic water supplies contain dissolved mineral. If the water in your area is hard it contains a lot, if it is soft water it has very little. (R-O water has none so espresso machines and coffee makers add some back for the coffee flavor molecules to have something to bond to). If I start to sound like “the Perfessor” that’s what they called me around the office. When the minerals dissolved in your water experience a violent temperature change in your H/W heater or engines it increases their tendency to fall out of solution. Usually they fall to the bottom of the vessel but they also attach to a surface such as your heating coils. The boiler of a scaled up espresso machine looks like an underground cave full of stalagmites. Soaking in an acidic solution dissolves the mineral build up but you need to be careful not to leave the acid too long because it will also attack your metal components.

If the water in your area is aggressive (acidic) to begin with it will attack the pipes leading to and in your house and pick up molecules from them so the scale can sometimes have a green tint from copper pipes or reddish tinge from ferrous pipes. Most scale is translucent white and becomes not visible when dissolved back into solution by an acid and drained out of your H/W heater.

The coils in our engine heat exchangers are hot so when cooling water hits them it throws a scale deposit.

It was fun for me to look back and re-think through all this, maybe boring for you.

[Tony Meola]

Yannis

The 6 gallons I gave you includes the exhaust. We like to see color run out the exhaust when we winterize. That means I am good and anything that would hold water that could freeze, and crack has antifreeze in it.

I would go with the 6 gallons just so I know the whole engine is full of vinegar. I would hate to go through all that and find out a spot wasn't cleaned out.

[Tony Meola]

Doug

Thank for the explanation. I actually have pretty soft water, and it is a Navien Combi. They tell me to flush the water heater side annually. They don't seem to recommend flushing the heating side which I find strange.

[Yannis]

Tony, thanks.

For us here who are not in the least concerned about freezing, how important is it to make sure that even the exhaust is full of antifreeze or vinegar?
How much should one be concerned about scale deposits alone, in the exhaust tube ?

[Amberjack]

Doug

Thank for the explanation. I actually have pretty soft water, and it is a Navien Combi. They tell me to flush the water heater side annually. They don't seem to recommend flushing the heating side which I find strange.

Tony, I can find my way around an espresso machine but not so much with a Combi boiler. The H/W side seems pretty obvious like any H/W heater—a continuous supply of fresh cold water is piped in, gets heated up and deposits scale in the process. I descale mine once a year and that’s it. As I understand it the house heating side in a combi boiler is a closed system warmed from a heat exchanger by the H/W. Maybe that sealed amount of recirculating water doesn’t carry enough scale to cause any buildup.

Back to Bertrams, I just scheduled the spring service for my Yanmars and will use the mixing elbows from HDI Marine in Vancouver WA-thank you for that recommendation. Even Paul at Marine Manifold in NY recommended them so I feel pretty comfortable with the decision. I’ll let you know how it goes and try to remember to take some images.

[Tony Meola]

Yannis

For preventing freeze damage pretty important the exhaust pushes out all the water and has antifreeze in it. For your situation, vinegar in the exhaust does nothing for the exhaust but lets you know the whole engine is filled and being cleaned out.

Just a matter of making sure is what I call it.

[Yannis]

I went down yesterday with a friend to see how to tackle the vinegar project.

I started the port engine and let it run until the temp reached the usual normal temperature when idling on the hard, Id say around 65-70 C. Despite that temperature (on the temp meter), the water was coming out almost cold out the exhaust. I don’t know how normal this is for the engine to have reached temperature while the exhaust water being barely lukewarm, so I shut the engine to avoid creating other problems, and removed the water supply.

I then turned the seacock shut, and connected a 1m garden hose to the barb on one side and into the first vinegar jug on the other. Restarted the engine and witnessed the vinegar being sipped in like a marvel...then into the second and third jugs until the vinegar was all sucked in, at which point I shut the engine again and let it sit there for about 45 mins. I went back and verified that the vinegar had reached all the way back the exhaust, by the smell.

After 45 mins I connected the water supply again and restarted the engine. I saw the initial water coming out of the exhaust have a blue green hue, the blue green color of “rust” that appears sometimes on copper tubes...this lasted for 3-4 seconds and then the water came back to its normal transparent color.
I have no idea why the exhaust water came out blue/green and if the vinegar diluted the metals inside and at which point, I hope not.
Let the engine run for a while on water and shut everything and left.

Ill be visiting the boat soon for the other side, I hope this green water was scale and debris deposited into the raw water circuit and not the result of a total dilution of metals, gaskets or anything else...

[S Ritzert]

That blue/green color was the corrosion on the copper. I know your currency isn't the same as ours, but if you have a green American penny, you can toss it in some vinegar, and the vinegar will turn green, and the penny will be nice and shiny copper.

My opinion is that you're not doing any damage with vinegar. in the US we can vinegar at different acidic levels. Most grocery store vinegar is really low%, if you want vinegar more acidic, you would get that from a hardware store.

Mostly what I see in the heat exchangers that I have cleaned have barnacles, and worm tubes. I don't know that vinegar will dissolve the calcium that these critters homes are made of. I use CLR or "The Works" toilet bowl cleaner to dissolve the calcium deposits.

I don't remover if I mentioned this before. On my 28, I have a flush system plumbed into my water strainers. When I kept that boat in a marina, I would close the seacocks to the water strainers, then hook my freshwater hose to the water strainers, and run the engines to flush out any saltwater, and critter larvae to reduce any growth in my cooling system.

I will see if I happen to have a picture of my flush system if you or anyone else in interested.

[Yannis]

Thank you Shannon,

So if the coper got rid of its rust and became all shiny inside, does this mean that the calcium scale has been eliminated too?

We do not have barnacles, at least not inside the heat exchangers, nor worm tubes.

[Tony Meola]

Yannis

I would think that some of it is gone but depending on how bad it was, a 45-minute soak may not have eliminated all of it. In order to keep the engine clean using vinegar would be do it every year.

Something like CLR will work better but in my experience using it to clean scale on the Furnace Humidifier, it takes more than 45 minutes, and that cleaning is done every year.

Personally, I would go with the Barnicle Buster and let it sit for about 6 hours.

[Yannis]

Tony,

I agree with the yearly use. That’s why I wanted to test it, as I did.

However, I believe that your furnace, any furnace, is a much friendlier environment for scale buildup.
Firstly, because it always operates at high temperatures, after all that is its purpose, and we know that scale deposits are produced with temperatures over 60C and the higher the temp the more the buildup. That’s why the furnace manufacturers advice is to operate all boilers and the like at the lowest possible temperature.

Secondly, the use of my engines per year for 30-50 hours is far far less than the operating hours of a household furnace. So less time for scale buildup.

As for the barnacle buster I don’t know anyone using it here, I don’t even know if the product exists, it may exist on the merchant marine application...we don’t have barnacles here. Or very few.

[Tony Meola]

Yannis

They call it barnacle buster, but it is designed for removing scale which is basically the same composition as barnacles.