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Boiler needs cleaning?

I have a 600 thousand BTU boiler that was installed about 50 years ago. I flush it out on a weekly basis starting from the highest to the lowest flushing outlet. Last summer, I had my heating contractor install some parts and he mentioned that the boiler should be descaled from the outside since there was quite a buildup of soot etc just above the gas flues and at the back of the boiler. He suggested that he clean the external soot so I gave him the go.
That fall, during boiler start-up I noticed that the lowest flush cleanout was expelling steam with very little water instead of water only. After a few months that cleanout was exhausting steam only. This was quite unusual but at least the boiler was still working. I decided to have the boiler cleaned out at the end of the heating season which was this past spring. There are no steam boiler technicians anywhere near me and I attempted to find out if there is a way of descaling the boiler from the inside using some kind of descaling agent. The water in this area has a very high hard water rating.
Question: Not sure if I should attempt to descale the inside of the boiler with some type of solution? And, if so, what would be recommended?
If I don't solve this problem I may have no choice but to replace the boiler.
Any suggestions would be much appreciated.



  • SlamDunk
    SlamDunk Member Posts: 1,592
    Just what you said. Find a descaling chemical, fill the boiler and let soak, hope for the best. We have a water softener on our feed water and we chemically treat our water.

    I would contact a company like Naalco in your area and ask them what to use.

    EBEBRATT-Ed Member Posts: 15,633
    If it's 50 years old it probably needs replacing. I would be cautious with chemicals on a boiler that old. Disturbing all the old stuff could cause a leak.
  • Steamhead
    Steamhead Member Posts: 16,904
    @galileo , where are you located?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • galileo
    galileo Member Posts: 13
    I'm in a small town, New Liskeard, in Northern Ontario Canada just below the 49th parallel. No one up here works on steam boilers anymore, unfortunately.
  • galileo
    galileo Member Posts: 13
    I have contacted a chemical company in Toronto, Canada asking them if they have any suggestions on what kind of chemical treatments are available for my boiler. They have, as yet, not responded.