Steam boiler addative

bowman

What is the opinion of the steam boiler experts regarding boiler addatives designed to reduce or slow corrosion?
Am old-school and typically never add anything to steam boiler water, but was suggested a rust inhibitor might be worth considering.
Do not want to add anything that might affect the boiler's ability to make dry steam and do not want to add anything that will later end up as sludge in the bottom of the boiler.
What do the steam experts have to say about this?
Currently have to add freshwater maybe 5 times per year.
Have very tight system, no leaks.
Manual fill only so can keep track.
Thank you

ethicalpaul

Add something that gets your PH to 11. Some manufacturers even outright recommend this. My favorite is 8-way. But don't add what it says on the instructions. Just add gradually until your PH is 11 and call it good. It does not cause surging. But you want your water to be clean when you add it. And adding it might make your water dirty so if that happens drain and flush then try again. Once the water is clean at PH 11, it will stay clean.

ChrisJ

I started using Steamaster tablets after I got tired of my water in my new boiler looking like chocolate milk.
Ever since it stays clear and I don't have to clean my gauge glass.

I don't think you can get the tablets anymore but I seem to recall 8-way being very similar.

Besides raising the pH these products also have corrosion inhibitors etc in them.

The downside at least that I've seen on my boiler was it appeared the high pH of the water erodes the gauge glass. I've replaced mine once in 12 years so far and I'd gladly do that over replacing a boiler.

Jamie Hall

First, do no harm. Second, it depends a lot on what your makeup water is actually like, and by extension how much of it you use.

If you are using a fair amount of makeup water, or that water is high in TDS and particularly chlorides, then a corrosion inhibitor is probably not a bad idea. It must be kept in mind, however, that the most effective ones are quite toxic, and if used, the operator must use personal protective equipment when doing anything which may result in exposure to the treated water. Further, don't expect them to protect anything except the boiler -- wet returns may not get enough treatment to make a difference.

(steam mains and dry returns won't get any with most consumer grade corrosion protection. There are chemical inhibitors which will travel with the steam, however you really don't want to play with them)

pH adjustment is another item. I agree that a slightly basic pH (say around 8 to 9) is preferable, but even going slightly acid -- to say 6 -- is not, in my opinion at least, going to create problems -- again, so long as very little makeup water is used. I'm afraid that I really can't advocate going into the strong base range -- 10 or higher -- not because it may cause problems in the boiler (it won't, so long as there are no oils present) but because, again, water with a pH greater than 9 (or lower than 4) is hazardous, and personal protective equipment must be scrupulously used (particularly for eyes -- full splash protecting goggles are a must, as are rubber gloves and aprons).

Jamie Hall

A PS, just for chuckles, from a completely unrelated field... forged iron items (e.g. swords and daggers) have been recovered from 2,000 to 3,000 year old burial sites in Britain, and are still quite usable, provided you sharpen them before use... they are rusty, yes, but ...

AdmiralYoda

The manual for my Peerless boiler says to keep the pH between 7.5 and 11. I try to keep it between 10-10.5 or so by using Rectorseal 8-way. Absolutely no corrosion and the water stays crystal clear. I think it takes me about a cup of the 8-way to accomplish this.

The 8-way does tend to clean slowly so it will dirty the water eventually. I replace the water and add fresh 8-way at the beginning of the season and at the middle. Just for the heck of it really. Fire up the boiler and let it run for a while to drive out any free oxygen when you add fresh water.

PMJ

@bowman,

I'm old school too and don't add anything. Haven't added anything in the 31 years I have run my boiler and it already had 35 seasons on it when I took it over.

I think the best boiler water for a closed residential system is water that has been boiled and condensed thousands of times. Nothing good comes in with fresh water so I just stay with the old stuff. The system is obviously very happy with the water the way it is and also probably happy that I don't allow a lot of fresh oxygen in after every burn cycle too.

There is no way I would risk upsetting this obviously happy system in a chemical add of some kind.

gerry gill

I'm currently using Rhomar 903 in my boiler.

ChrisJ

gerry gill said:

I'm currently using Rhomar 903 in my boiler.

How has your mini-tube system been?
I don't think I've seen any follow up videos on it or anything?