Demineralization filter

keith123

Anyone here use any generic Demineralization in-line filters for steam boiler make up water？

Hap_Hazzard

Within reason, minerals aren't harmful in boiler water. They tend to buffer the pH. Do you have unusually hard water?

keith123

What would you consider the best boiler water quality? Thank you for your response

Hap_Hazzard

pH should be between 7.0 and 8.5. I'm not sure about TDS and hardness, but you're probably not set up to measure them anyway. If those parameters are going to cause you any trouble, it would most likely be in the form of foaming, and you can test for this by bringing a panful of tap water to boil on the stove and seeing if any foam or scum forms on the surface.

If you have a water softener, do not use water that has been softened.

Most of us here are big fans of a product made by Rectorseal called SteamMaster Tablets. If you can find some, try them, but don't use as much as the label tells you to use. A little bit goes a long way.

nicholas bonham-carter

How much water are you adding to the boiler in a season?
A properly installed, and water tight system should need so little makeup water as to render a filter unnecessary.—NBC

keith123

Very little make up water. Just being OCD when it comes to make up water quality. I like to initial fill with distilled water and treat with steamclean

Hap_Hazzard

Distilled water is not a good idea. It has no dissolved solutes, so it tends to want to dissolve whatever it comes in contact with until it becomes saturated.

EzzyT

@keith123 we install those filters on every steam boiler install and Repipe we do.

keith123

A buddy of mine is high pressure steam operator in NYC and they constantly check the water quality. He told me who they use for this. I’m curious what their take on this is and what they look for

keith123

I’m finding so much conflicting opinions on the web. Some say demineralized and distilled water are ok. Others say not a chance. The Xylum website says it’s ok. Other sites claim it destroys black and cast iron. Yet the very process of creating distilled water is by collecting water from steam that has condensed. Very interesting topic

Hap_Hazzard

The reason water needs to be distilled to purify it is that it tends to dissolve everything it comes into contact with. You are, in fact, making distilled water in your radiators every heating cycle, but it's pretty far from pure by the time it gets back to the boiler.

Jamie Hall

keith123 said:

I’m finding so much conflicting opinions on the web. Some say demineralized and distilled water are ok. Others say not a chance. The Xylum website says it’s ok. Other sites claim it destroys black and cast iron. Yet the very process of creating distilled water is by collecting water from steam that has condensed. Very interesting topic

That's the nature of the web. But let's make sure we are all talking about the same thing here.

Distilled water -- water which has been evaporated, usually but not always, by boiling, and condensed in such a way that any lower boiling constituents are not condensed, and collected with little to no chance of ionic compounds or low boiling point compounds being collected. Usually, but not always, in glass. The stuff is very aggressive (there are remarkably few things -- mostly some plastics -- which won't dissolve to a certain extent in water).

Demineralized water -- a very poor catchall term which refers to water having been processed (several different ways) to remove "minerals" -- which are usually taken to mean Calcium and Magnesium ions, but often includes Iron(II) and Iron(III) and Manganese ions. Depending on the process, it may or may not have high levels of Sodium ions. Again, depending somewhat on the process, it can be quite corrosive, though not as fierce as distilled water.

Steam condensate such as is found in most heating systems isn't quite distilled water: it will very quickly pick up iron (usually II0 from the radiation or Copper, and will almost always pick up Carbon Dioxide. It's not particularly aggressive. Boiler water for high pressure process and particularly power, on the other hand, is very carefully treated for corrosion protection and anti-foaming; the chemicals used are not things you want to play with in a heating type setting.

For steam heating purposes, water with a near neutral pH and a reasonable level of dissolved solids is preferred. Corrosion protection may be added in hot water systems, if needed.

Hap_Hazzard

Good comment, @Jamie Hall. "Demineralized" is like the "reduced calorie" of water chemistry.

One thing I'd slightly disagree with is "near neutral pH." I don't think you want the pH to be any lower than 7.0, but a little higher is fine.

keith123

@Jamie Hall and @Hap_Hazzard thank you so much for your insightful responses. One product that I like to use with initial fill is Steam Clean.

I’ll look into the steam master tabs to use instead perhaps for my initial fill. But for the water source and make up water, what do you guys prefer to use? If the home owner is filling their own makeup water, are there any particular filters you like?

Thank you again for your insights !!

keith123

Thank you

Hap_Hazzard

I just use my regular tap water, which is moderately hard (~160 ppm CaCO₃) and pH 7.4 with a couple of SteamMaster tablets.

Jamie Hall

I just feed Cedric my regular tap water. It's slightly more acid than might be ideal, but it's relatively soft. Never given me a problem.

I'd only recommend a filter if the tap water had sediment problems (filters won't remove dissolved minerals) and you aren't likely to have that problem unless you have a poorly constructed well.

In fact, in general, unless your water quality is truly horrendous, no treatment (other than SteamMaster in moderation) is needed for residential steam systems.

hot_rod

I think the water for steamers wants to run a bit on the alkaline side, in the 8 ph range A small amount will coat the iron and help protect it from corrosion. I suspect the tablets buffer the ph up a bit?

Hap_Hazzard

The pH range should be 7.0 to 8.5 and the hardness should be high enough to buffer the pH but not high enough to form scale. Most excess minerals will precipitate out when it comes to a boil, so if you let some water out the drain cock after it cools down, you get rid of most of it.

The most important thing about boiler water is, don't change it more than necessary, and bring it to a boil whenever you add water. The more new water you add to a boiler exposes it to the worst properties over and over, whether it's scaling, foaming, corrosion or whatever.