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chemical cleaning of heater coil?

karpat8karpat8 Member Posts: 9
My Smith Series 8 heater coil had to be replaced because of buildup of deposits in the heater coils. The heater man that replaced it said he use to chemically clean these units but because of the difficulties of regs he no longer does them. I kept the old one with hopes of finding someone in my area that can either clean it or tell me how to do it and where to purchase the chemical and pump I will need to do the job. If anyone can help me in my search please let me know.


  • Steve WhitbeckSteve Whitbeck Member Posts: 669
    coil cleaner

    I usually use acid but the safe way would be to buy an on demand water heater cleaning kit. If it is totally plugged and can't get any water flow then it is scrap.
  • karpat8karpat8 Member Posts: 9
    white vinegar

    I've read a few comments on using white vinegar instead of some companies product for de-scaling. Have you heard of any con's concerning white vinegar? It seems if I already have a sub pump, hose, bucket all I will need to do is put a connector on the in and out of the tank-less coil and let 2 or 3 gal. of white vinegar run through the coil for 45 minutes. What do you think?
  • Jean-David BeyerJean-David Beyer Member Posts: 2,532
    White vinaigre

    I do not know if it is safe to use this in a boiler. But if it is safe and effective, you might wish to buy straight glacial acetic acid instead, as it should be cheaper and more pure. I use the stuff in photography and it used to be available in camera stores. Glacial acetic acid is about 98% concentration, where table vinegar is about 5%, so you will probably wish to dilute it. It comes in gallon jugs (and railroad tank cars, if you want a lot of it). Be careful with it though. Dilute it outdoors or under a fume hood. If you do not, it could harm your lungs. If you spill it on you, wash off immediately with lots of water.
  • icesailoricesailor Member Posts: 7,265
    Dirty Tankless:

    If what I understand you to say, and your boiler was changed because you had a dirty coil, Jose found you. The coil is replaceable. And cleanable.

    You can use White Vinegar if the water flows through the coil. And it sounds like it did. You may have to pump it for a long time. It's BS that White Vinegar is hazardous. It is found in salad dressing and my Newman's Own "Olive Oil & Vinegar is a staple of my dinner and I haven't suffered any adverse effects yet.

    I usually use 30% to 40% Muriatic acid that masons use to clean lime stains from brick. I cut it down. The worst coil I ever cleaned was one that plugged up after I started so I had to blow it back and forth with compressed air to get the chunks out.

    I hope that your boiler was old that was replaced. Everhot sells replacement tankless coils for even old boilers. The only reason to change a dirty coil is if the bolts holding the plate are rusted out and the gasket has been leaking for a long time. The gasket surface may be too bad for a new one.

    My opinion and experience.
  • karpat8karpat8 Member Posts: 9
    white vinegar

    After reading your comments I'm wondering if maybe I used the wrong heater man. My coil was not completely blocked but was somewhat restricted. It was taking a long time to get hot water to the shower and it was not lasting to long. The heater man just said the coil was getting blocked and installed a new one. I told him to leave the old one and I would see if I could either find a place that would give it an acid bath or I would see if I could do it myself. Now I'm wondering if there is a local guy that will once a year acid wash my existing coil. By the way the burner is only about 5 years old, it's a Smith series 8.
  • icesailoricesailor Member Posts: 7,265

    My solution to coils that don't heat that well is a water heater as a storage tank with a circulator. The coil doesn't need to heat as fast and will slowly heat the tank. In my opinion, it doesn't use a lot of fuel doing so because it only extracts heat as it is available.

    I use a 50 gallon elecrtic water heater and I DO NOT connect the elements to the electricity but only use the bottom thermostat as a switch to turn the circulator on and off. Its just a tank.

    I posted a few photos here but I'm clueless as to where. If you are interested, I'll find them and post them.

    I would have installed the water heater before I ever would have replaced the coil.
  • karpat8karpat8 Member Posts: 9


    Thank you for your suggestions. I've used a tank-less water heater system since 1986 and except for that one coil replacement it has served my family well. As I near retirement age it becomes about cutting costs. The added cost of purchasing (renting) a stand alone hot water heater and then paying to heat the water verses a yearly flushing of my tank-less coil seems more costly not less. I do appreciate your input and will give it much thought.

    Thank you
  • MikeLMikeL Member Posts: 145

    I have been using Rydlyme to clean coils for at least 20 years with fantastic results.
  • icesailoricesailor Member Posts: 7,265
    Replacement Coils:

    In the scheme of things,

    You have a new coil. There was nothing wrong with the old one. The replacement coil installer should have added cleaning ports and valves so it can be cleaned in the future. I would have added ports. Electric water heaters are the cheapest insulated tanks you can buy. The cost of a new coil is more than the cost of a 40 gallon electric water heater. After installing the water heater/storage tank, you can then turn the water temperature in the boiler down to 160 degrees from the 190 or 200 degrees you are set at now to get enough hot water. At 200  degree high limit, the operating control is set at 180 degrees or higher. You can set the operating control at 140 or 150 degrees. If you drop your water temperature in the boiler by 30 to 40 degrees, you WILL save significant energy.

    If you added an indirect, and cost the whole job out, you will never pay for the Indirect installation in savings over a storage tank only.

    There is no more problematic device than a hot water extender valve. They are almost always installed improperly and the thermostat element is burned out. The coils are dirty and ineffective. A storage tank smooths out all the problems and you have an even safe temperature at all times. Serious risk of scalding comes to mind.

    I turn my Symmons S96-1 single shower valve to the exact same position every morning and never make an adjustment until I am done and turn it off. You will NEVER get that with a hot water extender valve like  Watts 70A.

    Mine (and the many I have installed for customers) works very well for me and has worked the same in four houses I built for myself.
  • karpat8karpat8 Member Posts: 9
    coil cleaning

    I'm sure it is obvious that I am not a plumber or heater man so that being the case what is an extender valve. Seeing I already have the new heating coil installed and working fine I'm wondering what it would cost to have the service man install cleaning ports and valves so it can be cleaned in the future?
  • karpat8karpat8 Member Posts: 9
    coil cleaning

    I'm wondering what the main ingredient is in Rydlyme,is vinegar? Would I be paying extra for the name Rydlyme?
  • MikeLMikeL Member Posts: 145
    cost / benefit ratio............

    karpat: Rydlyme is an electrolyte that is non - toxic, biodegradable, safe to handle, extremely effective, and will not produce noxious fumes or corrode metals. Only you can determine if it has value for your application.
  • icesailoricesailor Member Posts: 7,265
    Hot water extender valve:

    Watts 70A Hot Water Extender Valve.

    I just had a delicious salad with avacados, tomatos, shreded cheese and assorted herbs and spices. All covered with olive oil and white vinegar.

    I use white vinegar to clean a dental appliance I wear in my mouth to keep me from wearing my teeth.

    I ain't dead yet.
  • karpat8karpat8 Member Posts: 9

    After the in coil was installed (2 years ago I think) we do not have to move the temperature setting on our Symmons shower valve either. We do have a Watts 70A hot water extender valve on our system and it does seem to be operating correctly.

    Thank you for all your insight and advice
  • SWEISWEI Member Posts: 7,356

    MSDS says 10% HCl.  Probably has some buffers in it to keep the damage down.

    You can buy HCl under the name "Muriatic Acid" at any pool supply - typically about 30%, though sometimes only 15%.  Be careful!!!!

    I generally use sulfamic acid to remove hard water residue, or citric if there's imminent food contact involved.
  • AlAl Member Posts: 170
    Maybe water treatment

    Running acid through a coil every year is usually not recommended, especially if the copper pits under the scale buildup, then the acid comes along, washes the scale away, and leaves a pinhole where the pitting was being sealed by the scale.

    My experience has been that "insufficient hot water" would be related to the outside of the coil (the part exposed to the boiler water) being dirty. "Low hot water flow" would be due to the internal part of the coil being clogged with scale.

    I think you're talking about the "low flow" condition. If so, you should consider treating the service water to prevent the problem in the future rather than acidizing the coil every year.

    I do water treatment work, and we install water softeners for this condition. I know there are others here who would disagree about water softeners, and maybe recommend alternative type treatment. Thats a subject for another thread, and you can research a lot of stuff on the internet, but I think that some type of treatment is preferable to acidizing yearly.
  • Aaron_in_MaineAaron_in_Maine Member Posts: 313
    Don't acid clean every year

    Don't acid clean it every year or you will be buying a new coil sooner then you like. If you do use acid or find someone that will do it you will possibly wear a hole in the coil and then need a new one anyway. One company I used to work for would acid clean coils with 50/50 results either the guy that did it(cause there was only one guy willing to do it) would run the acid through it too long and make a hole. Or not long enough and it would not do anything and someone would have to go out and change the coil anyway. Most on-demand water heaters however want a flush with white vinegar yearly so I see no problem with that and it's not as dangerous.
    Aaron Hamilton Heating
    [email protected]
  • karpat8karpat8 Member Posts: 9

    Good advice, thanks
  • karpat8karpat8 Member Posts: 9

    The more feed back I get the more I'm leaning to white vinegar. Thanks
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