HOw do you clean a tankless coil.?

Discussion in 'Tankless Water Heater Forum' started by bugguts, Jan 11, 2010.

  1. bugguts

    bugguts New Member

    Dec 13, 2007
    NYC Paramedic
    cen New Jersey
    After ruling out the taco mixing valve as the problem ( we hope)
    We reserached the problem a bit , and assume its a funky tankless coil.
    We get hot starts on the water........ ,then runs pretty kool...... and with this weather , Im kinda tired of cold showers at 5 in the AM
    So,,,,,, Im told muriatic acid ,,,,,,,, ?
    acid ratio to water .....?
    How,,,,,, run through ?
    submerge it?
    soak the Outside of the coil?
    have valves before and after the that helps....

    do we need a new gasket , or sealant?

    WJM in Joisey
  2. Master Plumber Mark

    Master Plumber Mark Master Plumber

    Feb 6, 2005
    Sensitivity trainer.. plumber of mens souls
    indianapolis indiana - land of the free, home of
    please c all someone

    you dont sound like you know what you are would be best to call someone

    you are supposed to use vinegar or CLR to flush out the innards of your tankless heat exchanger...

    if you dont have the isolation valves, it is nearly impossible to do without them...

    if you run muratic acid through your tankless heater you could void the warranty or ruin the unit...

    what brand do you have and how old is it...??

    have you ever run vinegar through it??
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  4. AAnderson

    AAnderson In the Trades

    Oct 25, 2009
    Aptos, CA
    Never use a cleaning solution that is not food grade rated and this includes muriatic acid and CLR. Use white vinegar, citric acid and or the available solutions for tankless heat exchangers.
    These are cleaned in place not removed and soaked.
    Could you post what brand this is and a few images if possible. Water going from hot to cold can have several causes, like insufficient flow, gas, fail to ignite, water servo valve and gas valve failure on some models, etc.
  5. ken jones

    ken jones New Member

    Feb 10, 2010
    hood river oregon
    what kind of pump do i need to clean the heat exchanger and where do I find It?
  6. AAnderson

    AAnderson In the Trades

    Oct 25, 2009
    Aptos, CA
    Any pump with plastic vane, 3/8' X (FITTING SIZE TO HEATER) 1/22 HP is fine. You are going to run the pump less than an hour. Use enough solution to fill the heat exchanger and the equal amount in a dedicated container with a sealed lid. Neutralize the solution when done and discharge where legal.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    Assuming you have isolation valves installed, you isolate it from the potable water supply, then substitute the new pump loop. Fill the system with the cleaning solution, then run the pump for awhile. When done, you flush it out, and put it back in service. How long and how much would be determined by how gunked up the system was and the manufacturer's recommendations.
  8. Gary K

    Gary K New Member

    Feb 16, 2010
    Burlington, Wa
  9. Plumbermurrieta

    Plumbermurrieta Plumber

    Feb 21, 2010
    Murrieta Southern California
    Acid can be pumped through the coil to flush out mineral deposits. If the flow has not been significantly this usually works well. This requires a specialized pump and is not a DIY project.
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