PH Level in steam boiler

Servicewiz_3

I would like to know what will cause a higher than normal, lower than
normal PH level. Also looking for help in adjustment of this level. Thanks!!

Jamie Hall

Consensus seems to be around 8 is good; 7 to 9 is certainly reasonable. Higher seems to give foaming, and lower may result in more corrosion (may not, too).

There are several products which one can add -- in small quantities -- to buffer the pH in a reasonable range.

As a general sort of rule, the feedwater pH is what determines the pH level, assuming one isn't adding treatment. There isn't much happening inside a boiler which will alter pH.

Erin Holohan Haskell

This article may help: https://heatinghelp.com/systems-help-center/the-importance-of-ph-in-steam-boiler-water/

ethicalpaul

I like to go higher than Jamie said. 10-11. You can even go way higher without foaming in a clean boiler, but there's probably little benefit.

If you twist my arm I'll tell you that the ph isn't nearly as important as making sure you don't have any steam or water leaks in your system.

ChrisJ

ethicalpaul said:

I like to go higher than Jamie said. 10-11. You can even go way higher without foaming in a clean boiler, but there's probably little benefit.

If you twist my arm I'll tell you that the ph isn't nearly as important as making sure you don't have any steam or water leaks in your system.

I'd rather leaks with a pH of 9+ over no leaks and a pH of 4.............

But that's me.

I also feel 7 is too low and 8 is iffy. I like 9, 10 is fine.

Pumpguy

In my experience, very high pH is corrosive to bronze pump parts.

In my days as a service tech at Nash Engineering, anytime we had a vacuum pump or gas compressor with a high pH carryover, ALL IRON construction was specified. This meant no copper alloy to be present.

I have also seen this corroded bronze parts in condensate and vacuum pumps used for steam heating systems. Again, this was traced to condensate pH being too high.

Never was able to determine what the pH limit was, but I like to say maybe 9 or so.

ChrisJ

Pumpguy said:

In my experience, very high pH is corrosive to bronze pump parts.

In my days as a service tech at Nash Engineering, anytime we had a vacuum pump or gas compressor with a high pH carryover, ALL IRON construction was specified. This meant no copper alloy to be present.

I have also seen this corroded bronze parts in condensate and vacuum pumps used for steam heating systems. Again, this was traced to condensate pH being too high.

Never was able to determine what the pH limit was, but I like to say maybe 9 or so.

I believe it also etches glass.
But my opinion has been I'd rather replace the gauge glass than the boiler.

So far.

ethicalpaul

Pumpguy said:

In my experience, very high pH is corrosive to bronze pump parts.

In my days as a service tech at Nash Engineering, anytime we had a vacuum pump or gas compressor with a high pH carryover, ALL IRON construction was specified. This meant no copper alloy to be present.

I have also seen this corroded bronze parts in condensate and vacuum pumps used for steam heating systems. Again, this was traced to condensate pH being too high.

Never was able to determine what the pH limit was, but I like to say maybe 9 or so.

I guess we don't know if this is a residential application, but there's nothing a typical home boiler situation can do about the PH of condensate...how high could condensate be anyway?

ChrisJ

ethicalpaul said:

Pumpguy said:

In my experience, very high pH is corrosive to bronze pump parts.

In my days as a service tech at Nash Engineering, anytime we had a vacuum pump or gas compressor with a high pH carryover, ALL IRON construction was specified. This meant no copper alloy to be present.

I have also seen this corroded bronze parts in condensate and vacuum pumps used for steam heating systems. Again, this was traced to condensate pH being too high.

Never was able to determine what the pH limit was, but I like to say maybe 9 or so.

I guess we don't know if this is a residential application, but there's nothing a typical home boiler situation can do about the PH of condensate...how high could condensate be anyway?

I honestly thought condensate, in a perfect world would have a low pH, of 4 or 5.

Pumpguy

I can't tell you how many times I have seen cast iron pump castings turned to graphite paste due to low pH.
Sometimes this graphite layer can be 1/8" or more deep .

The acidic condensate leaches out the iron, leaving the free carbon behind.

ChrisJ

Pumpguy said:

I can't tell you how many times I have seen cast iron pump castings turned to graphite paste due to low pH.
Sometimes this graphite layer can be 1/8" or more deep .

The acidic condensate leaches out the iron, leaving the free carbon behind.

But you've also seen condensate with a high PH?

Canucker

ChrisJ said:

Pumpguy said:

I can't tell you how many times I have seen cast iron pump castings turned to graphite paste due to low pH.
Sometimes this graphite layer can be 1/8" or more deep .

The acidic condensate leaches out the iron, leaving the free carbon behind.

But you've also seen condensate with a high PH?

If it has a high pH it's probably due to how clean the condensate is. It likely doesn't take much to buffer the solution

dopey27177

Me: In my time I found ph levels at 9 & 10 worked best in boilers.
Some jobs where ph levels reached above 10 foaming occurred.

Other chems to add were amines to prevent oxydation.

Jake

Pumpguy

ChrisJ said:

Pumpguy said:

I can't tell you how many times I have seen cast iron pump castings turned to graphite paste due to low pH.
Sometimes this graphite layer can be 1/8" or more deep .

The acidic condensate leaches out the iron, leaving the free carbon behind.

But you've also seen condensate with a high PH?

Yes, In one memorable case at a high school, the condensate had a yellowish tinge to it, irritated my hands, and had a slippery feel.

The iron pump parts were fine but the bronze parts were all shot.