Potable Water Through KA-6

Kungur · Post by **Kungur** » Wed. Dec. 10, 2014 5:25 pm

The added benefit of running our boiler year round is it acted like a dehumidifier and kept the basement nice and dry during the Summer.

jbarker3752002 · Post by **jbarker3752002** » Wed. Dec. 10, 2014 10:42 pm

I reconfigured my cold water inlet this evening and discovered that my problem is that the hot water coil in my boiler is partially plugged. I can only get about a pencil diameter of water to the nearest tap if I do not open the valve to allow cold water straight through.

I have to look into the best way to clean it out, but will most likely have to wait until I have an opportunity to shut the boiler down and let it cool. I have seen youtube videos that mention using a pump to circulate acid through the coil and back into a bucket....

Anyone have experience doing this as a DIY project, or is this something better left to a plumber? Luckily, I have valves everywhere, so it should be fairly simple to do, just not sure if I am looking for something like CLR, or something stronger.

McGiever · Post by **McGiever** » Thu. Dec. 11, 2014 12:22 am

Stronger...like Muriatic Acid get at Big Box store or pool supply store...1 gallon jugs...H Depot has 2x 1gallon jugs in a box...~$12.00

Post by **Rob R.** » Thu. Dec. 11, 2014 6:06 am

If your coil has plugged that badly in 7 years, you probably need a water softener.

blrman07 · Post by **blrman07** » Thu. Dec. 11, 2014 7:28 am

jbarker3752002 wrote:I reconfigured my cold water inlet this evening and discovered that my problem is that the hot water coil in my boiler is partially plugged. I can only get about a pencil diameter of water to the nearest tap if I do not open the valve to allow cold water straight through.

I have to look into the best way to clean it out, but will most likely have to wait until I have an opportunity to shut the boiler down and let it cool. I have seen youtube videos that mention using a pump to circulate acid through the coil and back into a bucket....

Anyone have experience doing this as a DIY project, or is this something better left to a plumber? Luckily, I have valves everywhere, so it should be fairly simple to do, just not sure if I am looking for something like CLR, or something stronger.

If you do it just like that youtube video your talking about it's doable. It may need a couple of shots before it's all the way open though. It will work. Just make sure you have the protective face mask, apron and such as this is acid your dealing with!!!

cn670 · Post by **cn670** » Thu. Dec. 11, 2014 8:23 am

Jbarker, you may want to clean your coil with it still in boiler for a quick fix for now. But I would do a remove and clean of the whole coil during annual maintenance . You may be surprised how much build up will be on the outside of the coil from sitting in boiler. I have a neighbor that cleans his coil every other year.

jbarker3752002 · Post by **jbarker3752002** » Thu. Dec. 11, 2014 9:58 am

Thanks for the help! I am headed to Lowe's during lunch to get a pond pump and some HCL to clean it this evening.

I will leave it flushing for a few hours to see how much the flow improves, then flush with clean water for a bit.

I will leave my plumbing alone now (I am sick of inhaling PVC glue, and will need the zone for my garage when I build it).

jbarker3752002 · Post by **jbarker3752002** » Mon. Dec. 15, 2014 11:22 am

I purchased a pond pump and then a bilge pump and neither had enough pressure to force water through the plugged coil.

I then resorted to a much stronger transfer pump and had a trickle coming through it at first, which slowly faded to nothing. At the moment, I have bypassed the coil until I am able to clear the blockage, but that may have to wait until I can shut the boiler down and completely remove the coil. At that point, I could submerge the whole thing in acid to dissolve the mineral deposits.

Since my household pressure was enough to force water through the coil (~40 psi), it is just a matter of applying enough force, I suppose....

McGiever · Post by **McGiever** » Mon. Dec. 15, 2014 12:08 pm

Residential water booster pump will give the pressure you need to push that acid cleaning loop.
Once it starts cleaning the minerals away the pump flow will get just better and better.

I would think that soaking coil in a acid bath will give poor results to the internal length of the coil.

oilman · Post by **oilman** » Mon. Dec. 15, 2014 1:58 pm

The Keystoker coil is quite large. If it is real bad, it might not be cleanable and would need to be replaced. Being so large, you need the proper set-up and patience to clean it. An acid bath will do nothing.( I do quite a few coil cleanings so I know what a PITA it can be).
As far as the outside of the coil is concerned, if you are getting scale on the outside, then you are taking in way too much feed water due to improper pump placement or piping. It should not be getting dirty. The only coils that would get dirty on the outside would be in an indirect water heater.

blrman07 · Post by **blrman07** » Mon. Dec. 15, 2014 4:23 pm

Did you try reversing the flow?

Post by **StokerDon** » Mon. Dec. 15, 2014 7:01 pm

blrman07 wrote:Did you try reversing the flow?

Good point there Larry. My coil actualy held house pressure on the inlet side with the outlet side completely disconnected. When I connected to the outlet side to house pressure, some big chunks blew out the inlet side. After flushing with just water, it was fine.

DHW Coil Mystery

Not that yours will be that easy but, reversing the flow will likely help.

-Don

blrman07 · Post by **blrman07** » Tue. Dec. 16, 2014 6:31 am

Excerpt copied from a readers comment at inspectapedia.com Link to full article. http://inspectapedia.com/plumbing/Tankless_Coil_Clogging.htm

Your information on how to remove scale in a tankless coil to improve hot water pressure and flow led to me doing this task myself. I am very mechanically inclined and rather technologically proficient but I still wanted to get an understanding of the processes.

I had a pump that would do the job but I was concerned about using an acid, even diluted.

I turned off the valves separating the tankless coil in my Burnham oil burner and luckily had tees in place already. All I had to do was get fittings for the garden hose adapters and screw them in place, I then connected the hoses to the pump and one to drain freely into my 5 gallon pail filled with about 2 gallons of water.

I then added a 28 ounce container of Lime-A-Way and started pumping. The water was nearly non-existent when I started and the pumps thermal overload went off giving me a break.

I did this pump on-thermal off routine about three times, each time letting the solution sit in the tankless coils for approximately a half hour. I was getting almost no improvement. I then decided to reverse the flow thinking what could be the harm. The pump started and the bursts of gray water were getting more and more frequent. After three more thermal overloads I was running freely.

oilman · Post by **oilman** » Wed. Dec. 17, 2014 6:08 pm

Larry has a good point. You always pump in backwards. On bad ones I can never get it to flow pumping into the inlet.

waldo lemieux · Post by **waldo lemieux** » Thu. Dec. 18, 2014 8:14 am

Try filling a long hose with acid solution using the pump, remove carefully from the pump and hook it to you hose bib(house pressure) and the other end to the coil and blast your way in. Running backwards with a full hose load will open it enough to be able to then use the pump and bucket method. Too I havent read the whole thread but when you start with the bucket, start with just water and add the acid a little bit at a time and when you stop getting bubbles out of the other end , stop and immediately rinse with clean water and baking soda. Then drink responsibly

waldo