Steam Boiler Water Treatment

Steve Fessette

The PH level in my boiler should be higher than 7 but lower than 11. Right now its at 12.89 and the water feels slippery to the touch. I cannot get anyone in my area to tell me what kind of water treatment in nessary to bring the PH down. I think I can remember an old school guy tell me to put sodium bicarbonate in the condensate tank to bring it down. Looking for suggestions.

nicholas bonham-carter

slippery water

that feels like water from a softener. what is the pH of the tap water, in your area[unsoftened]?

if there is a softener in this building, don't let its output, or the salt used to recharge it near the boiler, because of the danger of graphitic corrosion from the chlorides.

if softened water has been used in it, i would drain and refill with pure unsoftened water.--nbc

Jean-David Beyer

Slippery

Keep in mind that I am not a heating professional.

If water feels slippery, it generally means that it is fairly basic. pH 13 is almost as basic as water can get (pH 14 is the max). I do not know what the proper pH is for your heating system; it is certainly too high for a system with aluminum components in it.



First, find out what the proper pH should be for your system. Boiler manufacturer should be best source for that information. Assuming it is too high (I would guess that it is), it is desireable to find out why it is so high. High school chemistry would have you add a little hydrochloric acid to it at a time until you got the right pH. I urge you not to try it. The problem is that you want the pH to hold at the desired level, say for a year at a time, and there is no buffering if you titrate with an acid like that. Instead of playing bathroom chemist, I suggest you get in touch with water treatment experts familiar with home heating systems and follow their advice. Rhomar is one such company. Sentinel is another, but are based in England.

Jamie Hall

Could I respectfully enquire

how on earth it got that basic?  There is nothing (or should be nothing) in a residential steam boiler to alter the pH, at least not that much, and your tap water certainly shouldn't be that basic.



It is very rare indeed that one runs into a situation with a residential boiler where one has to add any sort of boiler treatment at all.  In fact, there are very few cases in which it is even recommended.



Unless your tap water is extremely basic itself (which should be investigated and corrected -- there are a number of health problems which can arise from cooking and drinking with water which is as basic as your boiler water is) I would recommend draining and refilling with pure tap water.  You may have to do this several times, if someone has added something to the system which is driving it basic.