Proper pH of a steam boiler

Mike_Sheppard

I have a customer that is being told by their chemical company that the pH of their boiler needs to stay between 11 and 13. This is a Weil McLain cast iron sectional steam boiler.

On my first visit I found they were maintaining the pH between 11 and 13. My litmus paper read closer to 14. They were having bad foaming and carryover. Flushing the boiler resolved the issue and I informed them it needs to stay between 7 and 9, as stated in the manual.

The chemical company is telling them I am wrong and it needs to be 11-13.

So I am posting this here so I can show it to the customer.

So, what is the pH in a steam boiler supposed to be?

Jamie Hall

I'll go with 7 to 9.

ChrisJ

Personally, I like 9-10 but 8 is fine. 7 is on the low side in my opinion.

11 is pushing it and anything above that there will be issues.

I also believe a high PH is known to etch the gauge glass over time.

Chris_L

Well, here is what one Weil MClain installation manual says (EG & PEG Series 5):
Filling steam boilers
1. Fill to normal waterline, halfway up gauge glass.
2. Boiler water pH 7.0 to 8.5 is recommended.
3. Follow skimming procedure.

nicholas bonham-carter

The manufacturer’s instructions should be more correct than anything the chemical company would say. Unless this boiler is generating steam for a process, and a lot of new water has to be added constantly, I would advise against any chemicals, unless there is a fresh water chemistry problem. Rhomar would be a better judge of better living through chemistry.
A few Steammaster tablets might be good however, if the incoming water is acidic, and might make the customer feel better.—NBC

ethicalpaul

Ever since having to replace my rotted condensate return nipple and Hartford loop, I've been trying to keep mine about 10 but I am working to balance rough boiling/carryover (I wouldn't call what I have foaming)

I actually have a hard time discerning between the colors for 9 and 10 on my litmus strips anyway

KC_Jones

At that PH I bet it is foaming like crazy. I wouldn't argue with them I would put the ball back in their court.

Ask them to please stop the foaming in the boiler and see what they say. It's a fact that high PH will cause foaming and improper performance, so since they are so knowledgeable ask them how to have high PH and not foam.

I'm not a pro, and even I know this stuff, I've seen it myself. Bring the PH down, and the boiler smooths right out.

DanHolohan

My thoughts:
https://heatinghelp.com/systems-help-center/the-importance-of-ph-in-steam-boiler-water/

DavidMitten

I used to be a paint detackification engineer. Try looking that one up on Google! It is an industrial water process. I also managed cooling towers, humidification systems, chillers, and portable boilers.
Without knowing what the water quality of a system is, I would advise keeping the pH at about 9. If it gets up to 10, that is ok. If it is at 8, that is ok too.
The higher pH passivates the metals in the system, thereby limiting corrosion.
It can be hard to keep a system pH up at 11 or higher. However, a pH at those higher numbers is like doing a "caustic boilout".
It will clean lots of stuff off the pipes and boiler and everything else and you probably will get foam.
The natural process of a system cycling(In other words, in the case of a boiler heating and cooling repeatedly)will raise the pH of a system. So, unless a system is very acidic, I would not consider adjusting pH.
One other thing I will mention about pH testing is that you can buy 2 or 3 pH paper kits. 1 will test for general pH. The other 2 can have much more limited ranges such as pH 7-8.5 and pH9-11. You can buy kits such as that from Cole-Parmer or Fisher Scientific or something. It beats guessing every time!

DanHolohan

Thanks for your insights.

Canucker

> @ChrisJ said:
> Personally, I like 9-10 but 8 is fine. 7 is on the low side in my opinion.
>
> 11 is pushing it and anything above that there will be issues.
>
> I also believe a high PH is known to etch the gauge glass over time.

You're correct on the glass. The glass is dissolving and clouding up

ChrisJ

> @Canucker said:
> > @ChrisJ said:
> > Personally, I like 9-10 but 8 is fine. 7 is on the low side in my opinion.
> >
> > 11 is pushing it and anything above that there will be issues.
> >
> > I also believe a high PH is known to etch the gauge glass over time.
>
> You're correct on the glass. The glass is dissolving and clouding up

I made the decision a long time ago that I'd rather replace the gauge glass than the boiler. So far though, in 8 years no issues.

Jamie Hall

ChrisJ said:

> @Canucker said:

> > @ChrisJ said:

> > Personally, I like 9-10 but 8 is fine. 7 is on the low side in my opinion.

> >

> > 11 is pushing it and anything above that there will be issues.

> >

> > I also believe a high PH is known to etch the gauge glass over time.

>

> You're correct on the glass. The glass is dissolving and clouding up



I made the decision a long time ago that I'd rather replace the gauge glass than the boiler. So far though, in 8 years no issues.

If the glass is being clouded by the water, the pH is too high. And may I add... if the pH is that high, the boiler water is hazardous (in water treatment, we regard anything at or over 11 as hazardous) and if there is a discharge -- say from a blowdown, or draining, or skim, never mind a pressure relief valve -- you must wear full wrap eye protection and gloves as a minimum.

ChrisJ

> @Jamie Hall said:
> > @Canucker said:
>
> > > @ChrisJ said:
>
> > > Personally, I like 9-10 but 8 is fine. 7 is on the low side in my opinion.
>
> > >
>
> > > 11 is pushing it and anything above that there will be issues.
>
> > >
>
> > > I also believe a high PH is known to etch the gauge glass over time.
>
> >
>
> > You're correct on the glass. The glass is dissolving and clouding up
>
>
>
> I made the decision a long time ago that I'd rather replace the gauge glass than the boiler. So far though, in 8 years no issues.
>
> If the glass is being clouded by the water, the pH is too high. And may I add... if the pH is that high, the boiler water is hazardous (in water treatment, we regard anything at or over 11 as hazardous) and if there is a discharge -- say from a blowdown, or draining, or skim, never mind a pressure relief valve -- you must wear full wrap eye protection and gloves as a minimum.

Like I said I run ,9-10 but id rather high than low.

I've never needed gloves and I wear glasses.

Jamie Hall

"Like I said I run ,9-10 but id rather high than low.

I've never needed gloves and I wear glasses. "

At 10 you're probably alight. Skin may feel a bit slippery if you get too much on you -- that's the hydroxide dissolving it and making it into soap (think lye plus fat equals soap). The cornea of the eye is the problem. And the wrap arounds are to prevent any splashes from getting into it.

ChrisJ

> @Jamie Hall said:
> "Like I said I run ,9-10 but id rather high than low.
>
> I've never needed gloves and I wear glasses. "
>
> At 10 you're probably alight. Skin may feel a bit slippery if you get too much on you -- that's the hydroxide dissolving it and making it into soap (think lye plus fat equals soap). The cornea of the eye is the problem. And the wrap arounds are to prevent any splashes from getting into it.

Between me and you, I try to keep boiler water out of my eyes. The whole, rust and 212f thing and all ...

Mike_Sheppard

I have found that following the manufacturer’s instructions generally works pretty well.

The customer understands now that 11-13 is too high. The last visit I made I found it around 8.5. Matching the chemical companies recent records.

Much better operation and no more breaking gauge glasses.

ksd99

How do you test the PH?

Jamie Hall

Hydrion pH test strips. Amazon.

ksd99

Buying now. Thanks.

Mike_Sheppard

These are the ones I use

https://www.amazon.com/dp/B07BPPDJQH/ref=cm_sw_r_cp_api_i_LwULCbPZQWCFW

ksd99

@Mike_Sheppard thanks mike.

PMJ

As @DavidMitten said, the natural process of repeatedly heating and cooling raises the PH. It doesn't just keep going higher and higher, but definitely does not go acidic on its own if no new water is being added. So the best water you can run in a boiler is water that goes in once and stays there. There should be no reason to add any chemicals as my Bryant manual states. It also says don't dump it out every year. What is already in there is way better for it than what comes out of the tap. My results clearly show they were right back in 1956. The longer the resident time of the water in the boiler the better. Fix the leaks!

Since my initial startup this season when I added a gallon or two after checkout I have not added any water. I verify the LWCO is working and keep the supply valve off. The nice big boiler has plenty of extra capacity to do many LWCO blowdowns without refilling. I am also convinced that natural vacuum operation which dramatically reduces the exchange of air between the inside of the system and the heating space also reduces water consumption and therefore corrosion. Open vented systems doing fewer cycles with longer burns which backfill the entire system with dry air from the living space every cycle and then exhaust it surely require more water. Running that way may humidify the living space, but I bet those boilers and pipes wish that be done another way.