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De-oiling a heat exchanger....what choice for cleaner?

dkmc

dkmc

Diamond
Joined
Jan 13, 2002
Location
Upstate NY -In the Flats next to the corn fields
This is a copper-brass system, it's a refrigerated air dryer. The compressor has oiled up the tubes and I'm trying to de-grease them. I pumped water with Dawn in it thru this thing for about 3 hours today alternating flow directions. It made piles of suds but it looks nearly unchanged from when I started. Any ideas on better chemical choices to get the job done? I'd rather avoid flammables like diesel fuel, etc. I thought about cleaning vinegar but I'm not sure if that'll cut oil as opposed to scale in a water filled exchanger.

IR air dryer.jpg
 
Sodium Hydroxide and water. Buy generic granulated drain cleaner and mix it yourself. It's very effective on oils and greases, as well as skin and eyeballs. Wear gloves and glasses. You won't have to run it for 3 hours either. Depending on the strength you mix, 15 minutes should be long enough.

It used to be the main ingredient in the better radiator cleaners until they started making the radiators out of aluminum.
 
Detergent and warm water should remove all the oil residue. Add a little bleach then flush with a garden hose. I'm Afraid of lye if the coils have aluminum fins. An alkali will attack the aluminum.

Roger
 
rogertoolmaker said:
Detergent and warm water should remove all the oil residue. Add a little bleach then flush with a garden hose. I'm Afraid of lye if the coils have aluminum fins. An alkali will attack the aluminum.

Roger
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The only contact will be with the internal copper/ brass components. Yes the fins are alu. but I can keep it away from them.
I did mention Dawn dish soap in water circulated for 3 hrs didn't hardly touch the oil residue. Maybe heavier laundry detergent?
 
dkmc said:
The only contact will be with the internal copper/ brass components. . .
Click to expand...

OK, then the lye will work wonders on oil, and with simple precautions is relatively safe to use. It also rinses clean with water which is more convenient than a dual treatment like solvent/soap. It is also mostly odor free, cheap and not flammable.
 
I'm sure solvent or even kerosene would work but it's 5 gallons just to fill the heat exchanger. And I don't think my plastic submersible pump would like it much. Water based solution is probably the way to go.

BT Fabrication said:
Run a solvent through it, then run soap and water after to clean out the solvent. then blow out with air. works the same way with oil filled air filters.
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Here in Philly , one can get 1lb jars of lye (pure NaOH) at the big Asian supermarkets. I use it to make soap.
Be super careful when handling and mixing the powder and then with the solution. Long sleeves, gloves, a face shield and good ventilation. Depending upon the concentration, it might get hot/warm when you mix it. Like acids, you want to slowly add the powder to the water not the other way around.
 
MrStretch said:
. . .it might get hot/warm when you mix it. Like acids, you want to slowly add the powder to the water not the other way around.
Click to expand...

Unlike some acids, adding water to dry sodium hydroxide doesn't produce a violent reaction in terms of bubbles/spray but it can get hot enough to melt a plastic container if the water is added slowly or is insufficient in quantity.

An example: Years ago I attempted to clean coolant and oil from a shop-vac hose by pouring a cup of lye granules into the hose and then running water in slowly. In a few seconds, the hose was clean and had a 3" hole melted in the low point of the loop. It all happened before I could agitate the hose and add more water.
 
dkmc said:
This is a copper-brass system, it's a refrigerated air dryer. The compressor has oiled up the tubes and I'm trying to de-grease them. I pumped water with Dawn in it thru this thing for about 3 hours today alternating flow directions. It made piles of suds but it looks nearly unchanged from when I started. Any ideas on better chemical choices to get the job done? I'd rather avoid flammables like diesel fuel, etc. I thought about cleaning vinegar but I'm not sure if that'll cut oil as opposed to scale in a water filled [heat] exchanger.
Click to expand...

As Gordon mentioned, a hot Lye solution will certainly work, and work well, but needs to be handled carefully.

What will also work, and is a lot easier to handle, is Alconox, also in very hot water.

Alconox was and still is the standard cleaner for laboratory glassware and metal equipment. I use it to this day. (My wife calls me "Chemical Ali".)

Alconox Powdered Precision Cleaner | Alconox Inc.

It is sold on Amazon by the box.

 
Joe, what about TSP ? Easy and cheap to get at walmart.



Joe Gwinn said:


As Gordon mentioned, a hot Lye solution will certainly work, and work well, but needs to be handled carefully.

What will also work, and is a lot easier to handle, is Alconox, also in very hot water.

Alconox was and still is the standard cleaner for laboratory glassware and metal equipment. I use it to this day. (My wife calls me "Chemical Ali".)

Alconox Powdered Precision Cleaner | Alconox Inc.

It is sold on Amazon by the box.
Click to expand...
 
What ever chemical you choose the hotter the water the better it will work. If you have a steam cleaner you might not need any chemicals at all. I would bet boiling water with Dawn in it would do wonders.

Connecting a garden hose to the drain spigot of a hot water heater is a good way to get a plentiful supply of hot water.
 
Last edited:
EDIT: Here's an article from Aug 18 2021 regarding states banning phosphates. Hum.....maybe I'm a couple weeks too late??
That figures.
:rolleyes5:
Are Trisodium Phosphate Substitutes as Good as the Real Thing? | Family Handyman


I do have a tankless WH so I wouldn't run out of hot water. But I'm recirculating the solution, no good way to keep it hot. Well, not without over complicating things anyway, which I can be pretty good at! Heh. Hopefully if I start with hot water it'll do it's job quick enough that it's clean before the solution gets cold.

oughtsix said:
What ever chemical you choose the hotter the water is the better it will work. If you have a steam cleaner you might not need any chemicals at all. I would bet boiling water with Dawn in it would do wonders.

Connecting a garden hose to the drain spigot of a hot water heater is a good way to get a plentiful supply of hot water.
Click to expand...

Interesting development. Just went to the hardware store to get some TSP. On the shelf where it was supposed to be there was an alt. product (not the green box TSP-PF). Sales guy says maybe they moved it, looks on the computer but spots the tag for it on the counter. Someone wrote BANNED on the tag with a red marker. No sign of it at Walmart either.

Joe Gwinn said:


TSP will work, so long as it is real TSP (Tri Sodium Phosphate), and not the green substitute, Sodium Silicate or the like. The "TSP" must contain phosphorus. Read the box carefully - many are misleading.

Amazon.com: Savogran 10621 Trisodium Phosphate (TSP) 1LB (16oz) : Health & Household

Alconox has much phosphorus as well.
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