Tube Cleaning

[slb8101]

What is the best way to clean enhanced cooler tubes in a centrifugal chiller? The tubes are coated with black iron oxide deposits, and the customer does not want to use acid to clean these tubes he wants me to use a brass brush on a tube cleaning machine. The customer has never had any water treatment to their chilled water loop and the building is 30 plus years old.

[absrbrtek]

The brass brushes or spin grit brushes. Depending on how hard the build up is, these may not take it off unless you use a new brush every few tube$.

[chiller mekanik]

First of all, I'm not a water treatment expert. But I know when I need help. At the very least I would seek the advice of my local water treatment guru & most likely would hire him. But, if you find out what chemicals will be best for your situation & you have the equipment to execute the cleaning procedure, go for it.

As far as the brass brush goes, not me.

The most important thing with enhanced tubes is the use of a reversible machine. Goodway also makes some tapered brushes that do a really good job with the grooves.

[kwhit]

I always use ceramic coated brushes

[txhvac]

I'd recommend to have the barrels acidizied. Those brass brushes may/ maynot work. Like Chiller Mekanik said use a reverseable machine, or you liable to unscrew your brushes :eek: that'll suck to get em' out. But, the customer's always right ??:rolleyes:

[consolidmech]

Try the dual diameter spin grid tube cleaing brush( Goodway). If may need to consult a water treatment specialist .

[absrbrtek]

I have used the brass brushes. They are softer than the copper. I was not impressed with the way they ground down on the scale after barely removing any from the tube walls. JMHO

I never got your email with the list changes. Any day now!!! :rolleyes:



First of all, I'm not a water treatment expert. But I know when I need help. At the very least I would seek the advice of my local water treatment guru & most likely would hire him. But, if you find out what chemicals will be best for your situation & you have the equipment to execute the cleaning procedure, go for it.

As far as the brass brush goes, not me.

The most important thing with enhanced tubes is the use of a reversible machine. Goodway also makes some tapered brushes that do a really good job with the grooves.

[bradysmill]

I have NEVER had any luck using ANY type brush on ANY type machine....when you have a significant build up of any kind.
Some brushes will attemp to do something but the "iron" build up as you are describing will need to be handled with chemicals.

I always consult the same chemical guys I have used for many years on most jobs. They shouldn't charge you for their time, just the chemicals, (labor is built into the cost of the chemicals)

For example, a good water guy should take a sample and first put a drop of hydrochloric acid on it, then if it bubbles up white, he will say it is calcium. He can tell you exactly what it is and what to use, then sell you the product with the instructions and ph levels to watch so you can do it.

First question is ---Is the cooler approach that lousy that you HAVE to clean the tubes or was it just noticed on a tube cleaning?

If it does have to be done, get your sample and find out what it is for sure, so you can get the right stuff.

I have taken chillers offline and used a citric acid in a mildly acidic PH (will not harm copper tubes) along with other products that will slowly take off the iron deposits and put them into solution instead of coming off in chunks, so that they can be blown down....It takes a gret deal of experience to just "clean tubes"

The citric acid is a little slower but.....will not harm the copper. I have seen guys use sulfuric acid and hydrochloric from United Refrigeration and dilute it, thinking they are doing a good thing.....when low and behold you see copper dust floating in the water when they are done....the tubes are shiny but where do you think the copper dust came from?

[absrbrtek]

Garranteed if you use hydroclhoric or hydrofloric acid you will have tube pitting when your done, even if you follow the instructions to the letter. If you leave it in to long you may be retubing the machine. :(

The citric acid is the way to go.
The citric acid is a little slower but.....will not harm the copper. I have seen guys use sulfuric acid and hydrochloric from United Refrigeration and dilute it, thinking they are doing a good thing.....when low and behold you see copper dust floating in the water when they are done....the tubes are shiny but where do you think the copper dust came from?

[heaviwall]

I had a similar problem in a GSA plant 8 -2500 t0n YK,s 2 driven by steam turbines THIS plant cooled all the smithsonians buildings we had black iron and also hi SRB,s The tubes in those machines were enhanced and very thin for efficiency The water boxes had the same black iron material on it as well we could not use brass brushes due to the thinness of the tubes.We had chemtreat come in to sample the water and they determined no water treatment was prescent.THIS was a NALCO job BTW. they found in the tunnels large leaks most of the chemicals was going down the drain.Cheamtreat chemically cleaned the tubes which took a lot of time but it was worth it.When we pulled heads on the evaporators the smell would knock you over.when the government measured the H2S gas it was extremely hi. nalco is still trying to get out of this .THIS WAS ALL ON CLOSED LOOP SIDE.

[slb8101]

I have NEVER had any luck using ANY type brush on ANY type machine....when you have a significant build up of any kind.
Some brushes will attemp to do something but the "iron" build up as you are describing will need to be handled with chemicals.

I always consult the same chemical guys I have used for many years on most jobs. They shouldn't charge you for their time, just the chemicals, (labor is built into the cost of the chemicals)

For example, a good water guy should take a sample and first put a drop of hydrochloric acid on it, then if it bubbles up white, he will say it is calcium. He can tell you exactly what it is and what to use, then sell you the product with the instructions and ph levels to watch so you can do it.

First question is ---Is the cooler approach that lousy that you HAVE to clean the tubes or was it just noticed on a tube cleaning?

If it does have to be done, get your sample and find out what it is for sure, so you can get the right stuff.

I have taken chillers offline and used a citric acid in a mildly acidic PH (will not harm copper tubes) along with other products that will slowly take off the iron deposits and put them into solution instead of coming off in chunks, so that they can be blown down....It takes a gret deal of experience to just "clean tubes"

The citric acid is a little slower but.....will not harm the copper. I have seen guys use sulfuric acid and hydrochloric from United Refrigeration and dilute it, thinking they are doing a good thing.....when low and behold you see copper dust floating in the water when they are done....the tubes are shiny but where do you think the copper dust came from?

To answer your question about the cooler approach, It is 10degrees @ 75% load and the machine will go into a surge past that. I would like to thank everyone for their inputs for my problem.

[IGBTech]

How long does it take when using citric acid? I've heard different stories. Also is it very expensive compared to the alternatives?

[hvacbear]

What is the best way to clean enhanced cooler tubes in a centrifugal chiller? The tubes are coated with black iron oxide deposits, and the customer does not want to use acid to clean these tubes he wants me to use a brass brush on a tube cleaning machine. The customer has never had any water treatment to their chilled water loop and the building is 30 plus years old.

Rydlyme is the best hands down. In Tucson ( Well water, Lo wet-bulb) we had great success.
In towers I put it straight into a sprayer and spot treated thick spots, and just let it run into the sump for circulation.

http://www.rydlyme.com/

[bradysmill]

How long does it take when using citric acid? I've heard different stories. Also is it very expensive compared to the alternatives?

It is a slower process but that is what you want---You never want to clean any tubes with a fast process.
Time to do the job varies on the condition of the equipment, size of the system ect........And you run the solution until it turns black from the iron coming off and keep testing the ph level.
As far as cost, Citric acid is cheap---$60.00 for a 50 lb. bag (Penna. prices)

I usually get stuff like that for free because we use the same company for all of our chemical needs.

[slimwoodie]

sulfamic acid ..???

[bradysmill]

sulfamic acid ..???

CITRIC ACID

[slimwoodie]

sulfamic acid is self neutralizing, at the proper concentration .

[cntrlvalchiller]

In refrence to Rydelyme. Works great just be careful can not be used if stainless (discolors) or some alloys and aluminum eats it and will also eat at copper if at 50/50 solution for extended period. Up side biodegradeable and you can hold in your hand although it will stain skin if contact prolonged though.

[absrbrtek]

Citric acid is also used as a food preservative for fruits and vegetables if you buy the food grade which you wouldnt.

[Snoring Beagle]

sulfamic acid is self neutralizing, at the proper concentration .

I like to use inhibited powdered sulfamic acid.
Works great, better if you can keep water at 120f to 140f.
Also use electronic Ph tester to keep track of when scale has removed.

Takes time though but is kinder and gentler on man and machine.

Use it lot on bundles and whatever the crew brings in to be "Boiled out".

Our chillers are run by a time is money mindset.
Boil 'em out with Hydrochloric fast. Works well with cold water and mixes easy but you can over dose easy too. Leaves lots of green residue on the floor when barrels are rinsed out.

Calcium can be some very hard stuff; Goodman machine and brass brushes just don't get.

I try not to get involved with the tower chemistry.
Too many cooks (chem geniuses) spoil the stew and I don't need no splaining to do when things go green or start foaming.