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Backwashing domestic tankless coil

HydroNiCKHydroNiCK Posts: 8Member
Hello everyone and Hi Ken Resnick,

I was recently bonding with my parents boiler and noticed there is a loop installed to backwash the coil.  How do I go about doing this?  The coil is 20 years old and I'm still getting sufficient hot water from it.  However, since i'm fascinated by heating and would like to practice my skills, and can't leave well enough alone... I am thinking about back washing it.  Now, I know how to backwash the coil with cold water but How do I do it with chemical?  I searched the wall so please forgive me if this topic already exists (I have a feeling it does)  please link me to it or provide the proper key words I should search ( I tried "backwash coil").  Also, feel free to let me know that i'm an idiot for contemplating using chemical on a coil that still works well.  However even if i don't use the chemical I still would like to know how to run it through.  Could I tie in a tee with a ball valve and male adapter so i could then hook a hose and pump up to the coil?  I would stick the suction end of the pump into the bucket of chemical.  Hook a hose up to the boiler drain on the loop to drain the chemical coming out of the hot side into a bucket therefore recirculating the chemical through my pump back through the coil?




  • SWEISWEI Posts: 5,540Member ✭✭✭✭
    Bonding with a boiler

    sounds a bit ephemeral to me, but you might try flushing coil' on

    Generally speaking, you recirculate treated water (almost always moderately acidic) through the piping or coil until it is free of deposits.  There are subtleties to the process depending on pipe/coil material(s), the deposited materials, and local water conditions.
  • HydroNiCKHydroNiCK Posts: 8Member

    Thanks SWEI
  • billtwocasebilltwocase Posts: 2,133Member ✭✭✭
    if it's not broken

    don't fix it. You could wind up with a pin hole or two. If you have any doubts, or having issues with hot water, replace it. Years ago acid flushing was done regularly. A lot of coils plugged, leaked, potential health hazard, etc. I know of no one who would take that chance today
  • SteveSteve Posts: 26Member
    coil flushing

    many years ago, i acid  washed / flushed   many coils....success rate was  about  30 %....i would not try today  because of  possible  health issues if  acid not fully flushed out....  replace the coil, or take to a radiator shop, & have them soak it in a cleaning tank for at least  4  to 6 hours....../    my  $.05    opinion...
  • heatpro02920heatpro02920 Posts: 991Member
    edited August 2013
    I agree

    With the others, if its not broke leave it alone, how water is fine, you want to do something flush it really good, but I wouldn't go running stuff through it and disturbing too much...

    You could end up bonding with some pretty stubborn tankless bolts..
  • Charlie from wmassCharlie from wmass Posts: 3,331Member ✭✭✭
    being a steam guy

    I steam clean the coils I deal with during the annual service.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
This discussion has been closed.


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