We have hard water and we heat our water with an oil boiler and a tankless coil. This is, admittedly, a very inefficient method of heating water but it came with the house so we are making it work. Once a year we need to have the coil cleaned so that we get full output again. In the past, our service company covered this under our contract, now they don’t so I have taken to doing it myself. Here’s how I do it:
Wayne WaterBUG pump (any plastic submersible utility pump works) – $100
Washer hoses (pair) – $15
2 gallons of white vinegar – $6
New 5 gallon bucket – $3
For a total of $124 plus tax, I have everything I need to perform the cleaning. Considering it was going to be $200 to have it done professionally, this was good. Also, next time it is only $6 for the vinegar.
Of note, I already had the tankless coil isolator valves plumbed in, if you don’t have these you will need them and they cost about $60 for the set.
Procedure: Turn off boiler, let it cool down to at 110F or cooler. Put pump in 5 gallon bucket. Fill bucket with 2 gallons of vinegar. Hook one hose from top of pump to one end of the coil. Hook other hose from remaining coil hookup and put the loose end into the bucket. Turn isolator valves off from water main and on to the pump and exit hose. Plug in pump, let it run for 1-2 hours. After that, I drained the vinegar and did the same process with clean water for a few minutes to get all the vinegar out.
It worked perfectly for us and is a known DIY solution, but I thought I’d share it here for you folks!