Heater Coil Descaling is NOT a maintenance thing

Sirocco Jerry

Active member
Heater Coil Descaling-

This is one of those things which fall into the question..
“What am I doing? Why am I doing it ? ..and is it essential ?
Rule #1- If there isn’t at least 200psi back-pressure pushing 6gpm through a ½” coil,
DON’T subject it to acid !
Besides the obvious reason, you might not realize a layer of hard-water calcium on the inside of the coil actually protects it from rusting away.
Here’s proof.. If you run purified water through your coil, like De-I water..
the water will “clean it” so thoroughly, “overexposing” the coil to water will rust away the coil to a blow-out in just a couple years.
.. Ask any truck rentalYard that has tried it.
Rule #2- IF you actually NEED to descale a heater coil..
DO NOT use Muriatic Acid ! Muriatic Acid is what we call a “spaz-attack acid”
.. it reacts with whatever it can eat the fastest, and likes iron as much as calcium.
IF you use an acid like Citric acid (that’s right, “Fruit Acid”,) you will be working much safer, more environmentally friendly,
and since the acid prefers calcium over iron.. You will probably not “CAUSE” a pinhole leak in your coil.
And yes I said “prefers” calcium.. it does still eat the rust, if that’s what’s troubling the flow through your coil. Here’s proof..
Our service center has descaled hundreds of coils over the past 30 years.. only ONE time did we lose a coil to a leak, and that was a 14 year old coil.
Rule #3- If you are not sure whether you need to descale your heater coil..
You either have not removed the hose from the outlet and tested the pressure pushing through it with a gauge,
..or you have not read rules 1 or 2.
Also- IF you need to descale, and you use the proper acid, you will do a better and faster job by using the system's pump,
which will not be affected by the acid, and if you have calcification in your coil, the pump and all the other fittings need descaling too
About running purified water through a coil..
If you try that, the water will no longer be purified.. you just contaminated it with corrosion or calcium,
and either will add water-spots to your otherwise pure water equation.
..Unless you invest in a Stainless Steel Coil.. which can cost 3 to 4 times what a standard coil costs.
If you are in the chemical processing business, and you want pure water heated for processing, Stainless is available,
and we have stainless coils still running strong at over 25 years old.
So, put a valve or Quick Coupler at the inlet of your coil, if you ever want to bypass it for running a spot-free rinse, without buying a stainless steel coil.
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Need some help on this one. It was time to change the water in the hot tube and trying to get it up o temp faster I thought I would fire off the hotbox and fill the tube that way. Anything for my baby girl, she's four now. The water was straight from the well, tried 250 degree to 100 degree temps along with cold water after hotbox cool down. I have not been able to retest with filtered water yet or water that has been through the softener and carbon filter..This was after the flush out of the hotbox that is normal. This was done with just a hose and ball valve. Any help. Is this just normal for iron in the water getting hot? Also let set for ten minutes and all that was there was light tan water that is normal water with iron in it.
Pics are hot than cold just the container and dwell time or sit time.


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