Last winter I asked if anyone had any ideas about how to get the calcium deposits our of a boiler heat exchanger. I inquired with Weil-McLain, and they said it needed an acid cleaning, and they have a technical bulletin on their website to explain it. That seemed to leave a number of questions un-addressed, so I called about 20 different heating contractors. I got an incredibly hostile reception from all of them. Some said the noise I was hearing could not be calcium deposits. Others said it was impossible to get the calcium out. Some did not want to even talk about it. Nobody would come and look at it.
Then last July, I made one last attempt to get a contractor to do the work. That guy blew up and accused me of trying to get free information. I figured if somebody would do the work for $500-750, I would have them do it. But there is a point where you might as well replace the boiler. It is small, so a new one would cost maybe $1800.
I found a product called Flow-Aide, and bought a descaling kit from them. It includes a bucket, pump, two connecting hoses, and a gallon of their product. I mixed the gallon with a gallon of distilled water, rigged up a discharge on top of the boiler, hooked pump output hose to the drain cock, and the return hose to my rigged opening. I let it circulate for 5 hours.
After one hour, two of the screws that hold the pump together stripped out and the pump began blasting product out the side in a fan shape. But it kept on circulating, and the leak was contained in the bucket, so I let it continue. The descaling product reacting during the cleaning emitted a powerful sulferous odor that filled up the whole house. The pump calls for 3/4″ hose, and they give you little washing machine hook up hoses that are less than 1/2″ I.D. So there is a high velocity of fluid dicharging back into the bucket. There was also some spray resulting from the broken pump.
Their instructions say to not get the product into the eyes, but I think they could emphasize it a bit more. If you fiddle with the pump, bucket, and hoses during the operation, it would not be hard for that high velocity return hose to rocket right out of the bucket and give you a face full. I can tell you that just one little speck of that product on your arm makes it sting right now. So, it is a very dangerous operation. The product rose in temperature during the cycle. The pipes were not too hot to touch, but getting close to that point. I don’t know if that was the chemical reaction or the heat of the electic pump.
But anyway, when I rinsed out the system, refilled it, and fired up the boiler, the crackling and popping sound was completely absent, so it worked. Some of the product got all over the concrete floor, and the heavy sulfur ordor persisted for over a week after the work. There was a lot of rust in the product / water mix, and that stained the concrete. So I washed it in vinigar, and then with TSP. The rust went away, and the odor has finally dissipated.
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Odd that all the heating contractors were so hostile. I suppose they know it's a nasty, time-consuming job, and they'd rather sell you a new boiler.
I think that when I described the noise symptoms to them, they got the impression that I knew something about the problem. I conclude that they only want to deal with customers who know zero about their trade. Definitely, they all would have preferred to sell me a new boiler.
The very last guy who chewed me out for calling him did offer some free advice, although in a highly begrudging manner. He told me to back the nipples out of the heat exchanger and look inside with a flashlight to see if there is scale inside. I am really glad that I did not try that.
One thing I noticed is that pipe threads these days seem to get tight earlier than they used to. With a 1/2" nipple, you can't get much more that 2-3 threads of engagement into a fitting. It makes it really hard when you are trying to end up with a fitting alignment when finished tightening.
Once finger tight, it seemed like one more turn was absolute maximum tightness.
I get the impression that they have loosened the tolerance on pipe threads to lower the manufacturing cost. And to be able to loosen the tolerance, it has to be toward increasing the interference.
heating contractors
A year ago our little boiler for our hot-water baseboard system went out. The blower fan that made it sealed combustion went out, and replacment pars were no longer available. I got some bids from $8000 to $10,500 to replace the unit. Then I found that the manufacturer did have a conversion kit to an atmospheric boiler, which would have worked for us.
I could find no contractor willing to install it. The manufacturer eventually offered to pay anyone I could find to do it, and one fellow who had quoted me $10,500 to install a new unit eventually said he'd do it -- providing I constructed a city approved structure around it (it's outside under an overhang). Never mind it's been there for 10 years already. When I finally told him I was going to do it, he backed out.
My experience is like yours, they are happy to sell you a new unit, but getting anything beyond minor repair or regular maintenence done is next to impossible.
I eventually wound up installing a brand new unit of the type they had recommended for about $3000.
I've been an industrial engineer for over 25 years. We used to clean boilers and heat exchangers using the pump and hose method with acid, but the equipment started to fall apart with pitting and had to be replaced eventually. We tried running deionized water through it to remove the scale, but it took several months and was very expensive. Nothing was working easy, so I decided to do a good bit of research. This is what I found out:
The scale is made up of Calcium Carbonate. Everything is made up of energy (even us). And all of it is either positive or negative in polarity. Calcium is a positive polarity and carbonate is negative. This is why they are attracted to each other and we call them both by one name (calcium carbonate). Now carbonate is higher in energy and is three times more negative than the calium is positive. So calcium carbonate is predomilately negative. Water is also negative in polarity. So calcium carbonate won't dissolve into water (salt is a positive polarity and this is why it perfectly dissolves into the negative water). Calcium carbonate just carries along with the water until the flow stops and scale forms as it drops out of solution. When cold water enters a hot environment like a water heater 50% of the calcium carbonate drops out.
So what I did was to convert the water to a positive polarity. Now the calcium carbonate dissolves into the water and can no longer drop out. It just carries along with the water until it goes down the drain. Positive water also acts as a powerful surfactant. It greatly lowers the surface tension (much better than soap). This hydrates the scale buildup and since the scale is now attracted to the water it is carried off. This process takes two to six weeks depending on the thickness of the scale and the water flow rate. The calcium carbonate converts to calcium aragonite. Looks and feels like baby powder. You have to flush this out of the boiler every two weeks until you see that the scale is gone.
The great benefit about this is the scale can no longer form. So there no need to ever use any chemicals or acid ever again. A very small thickness of calcium aragonite will coat all metal parts. It is not enough to cause an insulation barrier. But it keeps oxygen from getting to the metal. This prevents corrosion forever. Your boiler will run in perfect efficiency!
If you have any questions let me know here.
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Positively-charged water? I believe you have successfully described an acid.