cleaning heat exchange

sailaway78 · Dec 2, 2007

Heat Exchangefr

There should be no reason for the fresh water side of the HX to be fouled up, unless you have not used the proper coolant in it. As for the raw water side, it is pretty much as Tony B says. Make a connection point, behind the raw water strainer, and run three or four gallons of muratic acid through the system. Let it sit for four or five minutes, and flush with fresh water. And as Tony pointed out, BEWARE OF THE FUMES, they will certainly flush your sinus cavities. It's a simple, cheap and quick operation. They wanted three hundred bucks, I think thats the number, just to pull the HX off Tony's boat, plus the cost of cleaning it. Muratic is a couple bucks a gallon.

Dan · Dec 3, 2007

Muriatic

Do you dilute the muriatic and can you do this while the boat is in the water? Also please explain how you connected an extension hose to the hose from the raw water side. This does sound like a much easier way to do the cleaning.

sailaway78 · Dec 3, 2007

In the boat

Dan,You can do this in the water. Far as I know the muriatic is totally harmless once it dilutes out the exhaust. Just attach a hose to the raw water intake, anywhere behind the strainer. Easiest way is to use a same size hose, and tap in at the raw water pump. Be sure and shut off the raw water intake. The biggest, and about the only problem with this is the problem of getting away from the fumes. Be SURE you have very good ventilation, and do not breathe fumes. Muriatic is basically an acid that attacks organic materials, and is not harmful to metals, if it doesn't sit for long. Most of the boiler cleaners are just diluted muriatic. Five minutes will clean the HX pretty good. Basically if you pump three or four gallons into the system, let it set for five minutes and flush, you will have a clean HX.

Stu Jackson · Dec 3, 2007

Seems if you do this

and it eats up the zinc, it would be worthwhile to remove the zinc first and replace the bronze threaded cap, then do it.I'm having some difficulty understanding why anyone would even consider exposing themselves to the acid when all you have to do to clean the HX is either remove it or use some of the earlier suggestions.

Fred Ficarra · Dec 3, 2007

Hey Stu,,,,

to answer your question, refer back to my earlier post that starts with 'Ya know'.

sailortonyb Allied Mis · Dec 3, 2007

Dan and Stu

Dan: the muriatic was not diluted that is why it should be flushed out of there in no more than 5 minutes. This was all done while the boat was in the water. Not sure how legal it is though, but if you are environmentally conscious, the acid is eating away salt and calcium deposits. The calcium being basic and mixing with acid you get a salt and water solution as the result. I essentially just took a few hoses and clamps and more or less joined them together to make a longer hose. I suppose that you could disconnect the hose at the heat exchanger end and run a long one for this operation. We were just trying to get a job done as reasonably fast as possible. This is the easiest and fastest way to do it. The normal routine would be to remove the HX and 'boil' it in acid and then put it back together again. All we did was to skip the removal part and on my boat that could have taken a half a day or longer.Stu: I'm not familiar with product names, but I would never risk drilling holes or stuff rods through my heat exchanger coils. Also, I'm not sure if a gun cleaning kit would be able to remove hard calcium/lime deposits. Also, what alternative to acid is there for removing heavy calcium/lime deposits?BTW, this method was recommended to us by a marine mechanic that was too tied up to take on the job.Tony B

Stu Jackson · Dec 3, 2007

My earlier references were NOT to reaming out

the tubes, but rather to an in-place treatment, but with Lyme-Away rather than Muriatic acid. See #4 and #5.Fred, I know, ya know

jfssail · Dec 3, 2007

Chemistry !)!

Un-diluted Muriatic Acid should never be used to clean a heat exchanger. Muriatic acid, also hydrochloric acid comes in the concentrated form as 35% acid. For typical scale and iron oxide removal applications, it is used as a 5-7 % inhibited concentration. Diluting the concetrated acid with water is also a dangerous procedure if done improperly.Also the mixture should never be left for one hour in the heat exchanger.Also, this should NEVER be done with the heat exchanger in place. Much safer to remove the end cap and pour the cleaner in the open end and pour out and rinse.Most carbonate scales that form in our boat heat exchangers can be safely removed with less aggressive solvents like Lime-A_Way or CLR Lime removal. Lime-A-Way is 3% citric, 10% hydroxyacetic and 7.5% sulfamic acids. This acid works at room temperature, but can be used at higher temperatures for more aggressive scCLR is a mixture of lactic and gluconic acids. These are less aggressive solvents.By removing the heat exchanger and endcap, you will be able to see how the cleaning is progressing and replace the acid as necessary.Finally, you don't want an aggressive acid like Muratic being in contact with your pump seals.I have had 25 years experience in dealing with acid solvents for cleaning large latge utility boilers.Jack F Stewart1993 C36 #1233 "Windancer"Port Clinton, OH

Fred Ficarra · Dec 3, 2007

I love acid!

Sounds like the '60's huh?I keep a supply of Muriatic acid in the dock box. At home I've used it for cleaning shower tiles and toilets. It's good for removing rust from iron, steel or stainless. I've applied it directly to sails that were laid-out on my driveway. It removes the stains very well. It also cleans-up quickly with water. It's virtually harmless to the environment because it dilutes so easily. When it hits a large body of water consider it gone. We swim in it. It's used to control swimming pool PH. On the boat or in a confined space at home I've found that a 'gas mask' works to stop all traces of acid from reaching my nose. Get the kind of mask that shields the eyes too. Let's see what else? Oh. On the boat Muriatic acid is used to clean my LectraSan. I also remove rust stains from my watermaker components not to mention stainless rigging. As for cleaning a HX? Na, too much trouble. My drill is quick and a perfect fit.

RichH · Dec 3, 2007

I think you better re-read jfssail post again ....

Muriatic is NOT an acid that you want to 'play' with. Most of the those posters other than jfssail are WRONG and what they recommend is dangerous if you dont KNOW HOW to handle such strong inorganic acids. And YES you should only pour/mix 35% Muriatic INTO water and ............****NEVER EVER*** water INTO any concentrated acid as doing it in this sequence will/can generate a LOT of heat, steam, and 'splattering acid' that if it lands in your eyes will do permanent damage, if it bores through the upper layer of skin and penetrates down below the growth layer - permanent damage that only expensive skin grafting can repair, etc. etc. Acid INTO water and NEVER EVER water into acid. You're 'supposed to' learn that in high school chemistry. Even at 5-7% concentration, once the scale is dissolved the next thing to be attacked is the BASE METAL of the tubes and tube sheets. You want the de-scaler to contain INHIBITERS so that you dont acid-bore through those very thin walled tubes. "Rodding' out is insane in a thin wall tubed exchanger. There is NO corrosion allowance to the thickness of the tubes ... why in hell would you risk making them 'thinner' by 'rodding' or by ACID soaking. As for dumping the stuff overboard .... You really have NO idea of what you are doing. Such acid should ALWAYS be NEUTRALIZED (takes knowledge & know how to neutralize) before 'dumping'. So, if you dump and get caught (because you started a fish-kill, contaminated ground water, killed the vegetation, etc. .... you better be fully prepared to educate the judge of your precise chemistry analysis of the final 'mixture', etc. etc. etc. and why you ignored standard/common wastewater neutralization methods, etc. OR it 'may' going to cost you a LOT. RE-READ jfssail's post AGAIN as it contains IMPORTANT and chemically TRUE info, not a bunch of potentially very harmful wrongly deduced BULLSHIP.

sailaway78 · Dec 4, 2007

When you get

When you get your commercially available, enviro friendly, HX cleaner, read the label and see what it's contents contain. Want to bet a buck, it doesn't contain the aforementioned muriatic acid.