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End of Season Tips (1 pipe gas-fired steam)


I have a circa 1987 Peerless cast-iron residential gas boiler. Does anyone have experience using "8-Way Boiler Water Condition" from RectorSeal in this type of system? I plan on carefully reading and following ALL the manufactures directions.

Curious to hear any anecdotal stories. And most importantly, is this product more likely to extend the life of my old boiler OR shorten its life?


  • Jamie Hall
    Jamie Hall Member Posts: 23,442

    I've never been a fan of any addition of chemicals to low pressure steam boilers, but some people have had decent results with cautiously adding small amounts of pH control chemicals. Emphasis on small. Many are the tales on The Wall of adding too much — which is often the recommended amounts — and getting problems with surging and other unacceptable behaviours.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,099
    edited May 11

    @ethicalpaul may have some info on boiler chemicals like 8-way. Hopefully this tag will catch his attention

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • ethicalpaul
    ethicalpaul Member Posts: 5,735
    edited May 13

    Thanks Ed. Yes, I use 8-way primarily to increase the water's PH as Jamie mentioned.

    I do find the amount I add is quite a bit less than what is called for on the product's label. I add a little at a time (via my permanently-installed skim tap fittings) and test the water with cheap ph strips until it's around 10-11, which is what Peerless and other manufacturers recommend. At this level, iron oxidation is greatly reduced. Of course, Jamie's boiler is probably incredibly over-engineered with a literal ton of cast iron that will take centuries to rot out even at 7ph, but for the rest of us, I would certainly recommend 11ph. I assert that no commercial treatment will reduce the life of your boiler, so don't worry about that. Introduction of fresh water will, so generally, try to limit that. Don't flush your boiler for no reason, limit draining to just a gallon or less every season or two in order to prevent "mud" buildup. Keep a close eye on all steam or water leaks and fix them ASAP. Use manual makeup water as opposed to automated so that you know when leaks are happening.

    I did, for science, add a lot more 8-way to see if it had a negative effect. It did not, but my boiler was clean at the time. If your boiler has a lot of sediment and/or scale inside it, then 8-way and other similar products will loosen a lot of that up which can lead to surging.

    So generally I would recommend adding a little, seeing how it does for a few days, measuring the PH, then repeat as necessary. Be ready to drain some nasty water out if the product loosens up sediment.

    I have been experimenting with using pre-boiled water for makeup because city water has a lot of oxygen added to it for taste improvement. I am beginning to think that introduction of this aerated water is harmful to the life of your boiler.

    Here is the video where I added a ridiculous amount of 8-way to prove that this additive does not cause surging on its own:


    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el