# Acid cleaning domestic coil



## mark123 (Jul 3, 2014)

I was thinking of cleaning my domestic coil on my woodgun. Can I use hardware store muriatic acid straight out of bottle (30% strength) or should I dilute it? I am aware of all the dangers, but don't want to eat through the copper coil, does copper even react with hydrochloric acid?


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## hobbyheater (Jul 3, 2014)

*The Effects of Muriatic Acid & Copper*





*Resistant Metals*
Copper is often associated with noble metals for its resistance to non-oxidizing acids like muriatic (hydrochloric) acid. Copper is a not a noble metal per se like mercury, sliver, or gold, though it displays some of their properties in that copper will resist the degenerative reactions of muriatic acid in the absence of a catalyst. The catalyst in this case, is oxygen which bonds
	
 with copper to form copper oxide. Once bonded, the presence of oxygen enables muriatic acid to attack copper and over time dissolve it.


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## maple1 (Jul 3, 2014)

Have you ever had your water tested?

My old boiler went 17 years with no coil issues. Leaky coil gaskets yes - but the coil seemed to work the same all those years. Just thinking it may not be needed - my water is slightly acidic, with some iron & manganese but not enough to worry about according to that last guy I talked to.


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## mark123 (Jul 3, 2014)

We have hard water, I am am noticing much less flow with straight hot water than when it was new.


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## hobbyheater (Jul 3, 2014)

mark123 said:


> We have hard water, I am am noticing much less flow with straight hot water than when it was new.




Have you disconnected the cold water where it enters the heat exchanger , the build up may be at the fitting where the cold water meets the hot water at that first connection , not through out the entire coil .


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## maple1 (Jul 3, 2014)

If it does have a build up, I might try recirculating some CLR (or similar?) thru it. That's what I had in mind when I plumbed a couple of boiler drains into my dhw hx setup anyway - have yet to do it though. Try hobbyheaters suggestion first - at least see what it looks like in there.


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## hobbyheater (Jul 3, 2014)

Found this?

http://www.amazon.com/Rectorseal-68...qid=1404432542&sr=8-5&keywords=pipe+flush+kit


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## velvetfoot (Jul 6, 2014)

It's pretty nice that it's biodegradeable.  I will probably have to do an initial  flush on a new boiler, but don't know where to dump the stuff.


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## JMac23 (Jul 6, 2014)

Try some masons Lyme to neutralize the chemical.


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## cityboy172 (Jul 8, 2014)

We have used Apex rydlyme before with good results.


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## NE WOOD BURNER (Jul 10, 2014)

Dawn dish soap cleans out radiators and heater cores the best. in automotive applications. I wonder how it would do here.


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## Bob Rohr (Jul 11, 2014)

NE WOOD BURNER said:


> Dawn dish soap cleans out radiators and heater cores the best. in automotive applications. I wonder how it would do here.




If it is a hard water build up a mild acid is the way to go.  I have used Hercules Sizzle on both boilers and domestic water tanks and coils.  Also to clean toilet bowls that have stained from hard water leaking into them.  Follow the dilution instructions.

Those tankless water heater flush kits make it a simple task.  It is best to recirculate the fluid for awhile.  I would guess after it has cleaned the hardness it is safe to dump down the drain or outside.


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