3YM30 Heat exchanger cleaning

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KAM

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Just removed the exchanger for its 1000 hour service. The seawater side of the tubes are perfectly clean. There are small deposits on the freshwater side. I have cleaned most of it off with a pressure washer but the tube bundle is so tight its impossible to see the condition of the tubes in the centre of the bundle or attempt any mechanical cleaning. Any tips appreciated.
 
KAM said:
Just removed the exchanger for its 1000 hour service. The seawater side of the tubes are perfectly clean. There are small deposits on the freshwater side. I have cleaned most of it off with a pressure washer but the tube bundle is so tight its impossible to see the condition of the tubes in the centre of the bundle or attempt any mechanical cleaning. Any tips appreciated.
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Immerse in a suitable descaler ?
 
KAM said:
Yes I was hoping for a suggestion.
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Buy some inexpensive white vinegar on Ebay - by the 5 litre container!
Borrow somebody's jam making pan or something big and plastic, and WARM (NOT BOIL) enough vinegar to immerse the heat exchanger.
You should be rewarded by all the deposits bubbling away in good style.
Warm vinegar does this quite well, with less risk of any metal damage than using anything with HCl in it!

Repeat if you think it is needed?
 
KAM said:
Just removed the exchanger for its 1000 hour service. The seawater side of the tubes are perfectly clean. There are small deposits on the freshwater side. I have cleaned most of it off with a pressure washer but the tube bundle is so tight its impossible to see the condition of the tubes in the centre of the bundle or attempt any mechanical cleaning. Any tips appreciated.
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It's the seawater side that is prone to calcium build up. If you use soft water + antifreeze or pre-mixed coolant I can't see how you will ever have any problems on the freshwater side. However, now you got it out you might as well use acid on it.

I was going to remove the exhaust elbow and H/E on my 3YM30's as they had never been touched after 6 years and 3000 hours. I removed the elbows first and they were both absolutely clear of any build up so I didn't bother disturbing the H/Es.

Richard
 
My exhaust elbow looked like new inside and out but I was surprised at the crud on the fresh water side of the heat exchanger. I used very soft water but did use blue antifreeze for the first couple of years before changing to red. This may have caused the problem and would be interested to know what chemical reaction would cause this. I think its worth cleaning the tube bundle as its very tightly packed and the flow rate over the outside is probably not very fast or uniform as it is effectively sitting in the bottom of a tank. Its quite a simple job.
 
I went through each tube in the bundle with a piece of #14 stranded copper wire and WD40 (as a lubricant). I took about 3/4 of an inch of the sheathing off and adjusted the end so that it would scrape the sides of the tubes. Not sure that this was required but I was able to see a noticeable difference in the size of the tubes after having done this. It was tedious. I used wire because I could not find a brass galley brush long enough to pass through the entire tube.
 
Seadawg33 said:
I went through each tube in the bundle with a piece of #14 stranded copper wire and WD40 (as a lubricant). I took about 3/4 of an inch of the sheathing off and adjusted the end so that it would scrape the sides of the tubes. Not sure that this was required but I was able to see a noticeable difference in the size of the tubes after having done this. It was tedious. I used wire because I could not find a brass galley brush long enough to pass through the entire tube.
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I think that's the seawater side though and it's the freshwater side which is giving the OP grief.

Richard
 
OK so the problems is not really bad but I would like to get it clean. I have tried vinegar and 10% phosphoric acid but it does not react with the deposits. The deposits scrape off easily with a finger nail from the outer tubes. I used to run on blue antifreeze but changed to red as recommended by the manufacturer a few years ago. I did drain thoroughly but there may have been residual blue in the system particularly the calorifier. So the deposits could be silicates precipitated by the reaction between red and blue antifreezeor is this just a myth. Unfortunately the internet is clogged with rubbish on this subject so would appreciate comments from any chemists out there as to what the deposits may be and what may remove them from the centre of the bundle.
 
KAM said:
OK so the problems is not really bad but I would like to get it clean. I have tried vinegar and 10% phosphoric acid but it does not react with the deposits. The deposits scrape off easily with a finger nail from the outer tubes. I used to run on blue antifreeze but changed to red as recommended by the manufacturer a few years ago. I did drain thoroughly but there may have been residual blue in the system particularly the calorifier. So the deposits could be silicates precipitated by the reaction between red and blue antifreezeor is this just a myth. Unfortunately the internet is clogged with rubbish on this subject so would appreciate comments from any chemists out there as to what the deposits may be and what may remove them from the centre of the bundle.
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Maybe try a radiator cleaner. ??? Wynn's radiator flush was mentioned recently. Vyv Cox said he had found it effective.

Even if it does not dissolve the deposit ( I'm sure it won't) perhaps it will loosen it sufficiently for pressure washing to remove it.


( Must flush systems thoroughly if changing antifreeze type I think I have even read, "clean with oxalic acid".)
 
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