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chemical treatment for hw systems

steamfitter Member Posts: 156
I was wondering if there is any use for chemical treatment in small residential hot water heating systems.
Are they ever used? If so, how effective are they in preserving the boiler and piping?


  • hot_rod
    hot_rod Member Posts: 22,262
    A lot depends on how good the fill water is. Chemical conditioners can help "fix" bad water.

    If the boiler is a leak free, sealed system and it is commissioned with demineralized water with proper ph the system should be fine for decades with just water.

    Another important part is keeping the system O2 free, hard to do. Most all of the plastic and pex tubings allow some O2 ingress. Air vents, pump seals, valve packings can also allow o2 into systems. O2 is what leads to corrosion. Keeping good water in and, oxygen out, is the key.

    Boiler conditioners include O2 scavengers, ph buffers, and film provides to protect all the multi metals in the system. If you chose to go the chemical route, you need to check, maintain and occasionally add boosters to them. Depending on the condition of the system and O2 ingress, again.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • steamfitter
    steamfitter Member Posts: 156
    Thank you Hot Rod!
    valuable information!