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PH testing

ChrisJ Member Posts: 15,914
What is the easiest way to check the PH of your boiler water?  Most of the strips I find seem to be for urine and saliva, will they work with water?

Also, does the PH of boiler water change even if you don't add makeup water?  Does the mixing of carbon dioxide in with the water  increase the PH enough to matter over time?


Chris J
Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment


  • icesailor
    icesailor Member Posts: 7,265
    PH Testing.

    You can buy a PH Pen. They aren't cheap. Or you can be cheap and goo to a pool supply store and buy a pool PH test kit. They are cheap. Probably $25.00 or less.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Easiest way?

    The easiest way to test pH of water solutions is with those paper test strips. Easy, but in my experience as a photographer who mixes his own chemistry sometimes, not very accurate. It is really difficult to assess the color of the wet paper  in comparison to the colors on the code strip, and I am very good at recognizing color differences.

    I also have a Hanna Instruments HI96108 pH tester. it is not quite so easy for a homeowner to use, because I must calibrate it every time I use it. If I were a professional using it every day, I would probably have to calibrate it only once a day. It claims to have automatic temperature compensation, but it does not seem to handle the following problem.

    The water I test must be very close in temperature to the buffer solution temperatures I use to calibrate it. In other words, if I calibrate it at room temperature (say 70F) and draw some 110F water from the boiler, it will give incorrect readings. And if I leave the boiler out in a little cup to cool down, it will absorb CO2 from the air and become more acidic. My solution is to wait until summer when the boiler is not heating the house, and picking a time long after the boiler operated to warm up the indirect hot water heater. I do not know how professionals deal with this.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846

    I use my pool reagents for testing. They sell pH-only tests that are pretty inexpensive and fairly accurate.

    The chemistry of boiler water does change significantly from the chemistry of the makeup water, but after a few heating cycles it should stay fairly stable. Heating water drives out all the dissolved gases and causes minerals to precipitate. Any gases that make it back into solution usually react with the dissolved iron to form rust, which also precipitates out.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Chris_83
    Chris_83 Member Posts: 24
    PH Test Kit

    How accurate does the ph testing need to be for a home boiler?  Would test strips like this http://www.freshwatersystems.com/p-491-ph-test-strips-50.aspx be good enough?
  • gerry gill
    gerry gill Member Posts: 3,078
    yes Chris,

    those would work out just fine.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

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