Whether to clean an old boiler/what anti corrosive product to use .

Southboy

I have a 2 pipe steam system fired by a HB Smith Cast Iron Boiler that is perhaps 35-40 years old and working OK. To my knowledge, the boiler has not been cleaned in many years. I have been advised by a heating technician to be cautious about using any cleaning product, as it might remove some internal rust that is creating a seal or affect the boiler seals. Any suggestions? The second matter is whether to use an anti corrosive additive during the season and off season. I have read the opinion here and elsewhere that a steam system should be totally drained off season. I have had to replace some of return wet piping that began to leak, that was probably 90+ years old. I wish to maintain the system as best I can. Any suggestions? What is any anti corrosive product is recommended--Fernox ? Rectorseal 8 way ?

Hap_Hazzard

Before you consider adding anything to the boiler water, you need to know what condition you're trying to address. If your water is reasonably hard, alkaline and low pH, you don't need to add anything. Just make sure you address any leaks—steam and/or water—so you're not adding a lot of makeup water, and when you do add water, do it when the boiler is about to start a heating cycle so the oxygen in the makeup water will boil off.

If you have soft or acidic water, you will need to treat it, but this is relatively unusual.

Corrosion is a process of oxidation, so oxygen is your enemy. That's why most people don't recommend draining your boiler for the summer. You'll never get all the water out, but you'll be letting lots of air in, and the shallow pools of water left behind will absorb oxygen from the air and attack your boiler. If you want to do a thorough flush, you can drain the boiler, refill it, and turn on the burners until the water starts to boil. Never leave fresh water standing in a boiler without boiling off the oxygen.

Jamie Hall

You have hit a can of worms, where there are, in fact, widely differing opinions -- and remarkably little hard research.

If you were to ask my opinion, first, there are two things about cleaning. There is the fire side. This tends to collect soot, particularly if the combustion isn't spot on. This should, ideally, be cleaned ever year. Then there is the water side. Other than occasionally draining excess sediment out of the bottom of the boiler, not only is there no need to clean it, it's inaccessible -- so the only way you could clean it is with a chemical or some kind. I'm going to agree with your technician -- so far as the water side is concerned, don't worry about it -- and for goodness' sake don't put any cleaning products in it.

For that matter, I wouldn't put anything in a steam boiler for most heating uses, unless the pH is way off, in which case there a things which can be added -- with great caution -- to adjust and maintain the pH. There certainly is no need for any anti-corrosive product in a residential steam boiler.

There is a school of thought which suggests that a residential steam boiler should be drained in the off season. There is another school of thought which suggests it should be flooded. And there is a school of thought which suggests it should simply be left alone. I belong to the latter. Why? Assuming that you haven't been adding a great deal of water during the season (if you have, that's a different matter), and assuming the boiler is cast iron, the water and the iron will have done any chemical reacting -- rusting -- they are going to do long since. Further, this applies to the entire system. The chemical reactions -- rusting -- require oxygen, and a steam system is pretty much closed when it is not in use. Any oxygen in there will be used up and any reactions will cease.

If you are going to drain it, it would be wise to figure out a way to provide a protective film of some kind on the boiler internal surfaces, which will be exposed to damp air and may, indeed, rust. Trouble with that is that you have to get rid of that coating when you fire it up in the fall. Not an easy job.

cross_skier

Agreed there is little research.  @New England SteamWorks puts king valves on their systems, blowdowns are a part of their annual maintenance to clean the water side the boiler.  They state this is is helpful but it is not clear what pressures they target in their process or what the measurable results are.

Derheatmeister

Hap_Hazzard said:

Before you consider adding anything to the boiler water, you need to know what condition you're trying to address. If your water is reasonably hard, alkaline and low pH, you don't need to add anything. Just make sure you address any leaks—steam and/or water—so you're not adding a lot of makeup water, and when you do add water, do it when the boiler is about to start a heating cycle so the oxygen in the makeup water will boil off.

If you have soft or acidic water, you will need to treat it, but this is relatively unusual.

Corrosion is a process of oxidation, so oxygen is your enemy. That's why most people don't recommend draining your boiler for the summer. You'll never get all the water out, but you'll be letting lots of air in, and the shallow pools of water left behind will absorb oxygen from the air and attack your boiler. If you want to do a thorough flush, you can drain the boiler, refill it, and turn on the burners until the water starts to boil. Never leave fresh water standing in a boiler without boiling off the oxygen.

I do not understand how water can be reasonably hard, alkaline and low pH at the same time..
Can you please explain this?

Derheatmeister

I am wondering if anybody uses "High purity water"(Deionized Water) as Water in Steam systems..

cross_skier

I understand distilled water is bad as it picks up a lot of oxygen.  The goal is to keep pH around 10 to inhibit rust and to remove chloride

https://forum.heatinghelp.com/discussion/comment/1678784#Comment_1678784

KC_Jones

There are several of us that will advocate for water treatment for a steam boiler. The boiler is a major investment for any residential property so why not give it the maximum chance for longevity?

My PH is currently between 10-11, water stays clean and I see virtually no sludge/corrosion buildup.

As far as cleaning a 35-40 year old boiler. If I was to do anything I would wand it out to remove any accumulated sludge/sediment, then refill with some water treatment. I don't think I'd use chemicals to clean, mainly because I think the wand method is more effective.





https://www.youtube.com/watch?v=q1tw9rz-pUk

Hap_Hazzard

Derheatmeister said:

I do not understand how water can be reasonably hard, alkaline and low pH at the same time..
Can you please explain this?

Sorry, I meant high pH.

cross_skier

Very interesting.  Have you used a wand on an older boiler?  If you did it pull a lot of crap out?

It would be great for a new boiler as oil tends to float.

Do you think a sludge or wet vac would help when wanding an old boiler?

Derheatmeister

cross_skier said:

I understand distilled water is bad as it picks up a lot of oxygen.  The goal is to keep pH around 10 to inhibit rust and to remove chloride

https://forum.heatinghelp.com/discussion/comment/1678784#Comment_1678784

Since O2 is not something that is removed in the process of creating Deionized water that is something that i never heard about.. i will check on that !

If the recommended PH on Steam boilers is at 10 i wonder what happens to all of the minerals of which brought it up to that level in the first Place..
I am Guessing that they will settle out in the HX, which then needs to be removed as it builds up after a while.
I understand running it somewhat on the Alkaline side to avoid corrosion.
IMO Chloride would not be an issue with Deionized water..
Some european locomotive/steam engine operators used Demineralized/Deironized water dating back to the 1800..

While we are talking about cleaning Steam systems using chemicals:
During the duration of having Chemicals installed in the system and as it is being cleaned the Radiators may Vent the chemicals into the rooms...
Is there any concerns with the Chemical Vapors entering the rooms..
Especially if someone with a Autoimmune related Heath issues/Respitory concerns is subjected to these Chemicals..
Please read this Safety data sheet regarding some of the Chemicals https://www.rhomarwater.com/pdf/Steam-Pro_SDS_Rhomar Water.pdf

delcrossv

The real trick with an older boiler is gaining access. Those plugs really don't want to come out.
I've been using 8 way with pretty good results.

Jamie Hall

The really key question in all of this is... how much water are you adding? If you are adding a good deal of water, then distilled or deionized water treated with a buffer to maintain pH is probably a good idea, if you are in a situation where you can't blow down the precipitated minerals. You will need a buffer; neither distilled nor deionized water has much in the way of buffering capacity and the pH will tend to be below 7, as carbon dioxide is dissolved from the air.

If your water consumption is high -- more than a gallon a week or so for a residential system -- and you are not using deionized or distilled water, you will definitely want to blow the boiler down probably annually, and you may find that scaling on the water side is a problem if the water is also hard.

Plain tap water usually has a pretty decent buffering capacity, but even so if it is really acidic it may not be a bad idea to add some treatment to raise the pH. It is even more important to avoid chlorides. They are not usually a problem -- again -- in many tap waters, but in some localities they can be remarkably elevated (almost always from road salting; very rarely naturally). if you are on well water, your local health department can test for them. If you are on city water, the water utility should have that information. Softened water is another matter. If your water is naturally hard, the pH will usually be quite reasonable and, if you are not adding much water the hardness compounds should not be a problem. However, there are several approaches for softening water, and they all reduce the buffering capacity and pH may not be reasonable. Worse, the most common approach is ion exchange softening, and that substitutes chloride for the hardness cations. Therefore softened water should never be used as a boiler feed.

Somebody mentioned steam locomotives. To the best of my knowledge, except in the desert areas of the west and southwest, local tap water was used in North America. I believe that there were a few European engines (and South African) which were closed cycle, with condensors, which by definition produces distilled water, but North American steam was (and is!) all open cycle (there were a couple of condensor equipped engines in North America -- Delaware & Hudson had one, and I think Union Pacific tried one -- but they were maintenance nightmares and quickly scrapped). Solids did build up in locomotive boilers, and they are blown down actually fairly frequently during a day's operation to get rid of the solids. In the desert regions, water sometimes had to be imported (one of the reasons for the switch to diesels) for the engines, as the local water was alkaline and gave terrific trouble from priming and foaming.

Other power boilers -- particularly marine -- are usually closed cycle, and a great deal of attention is paid to water quality, as they are also usually steel, which does rust. Some remarkably nasty chemicals are used to control that.

cross_skier

I have a 1-1/2" nipple on my Peerless input.  I may try to wand/vacuum it  this summer. 

When I reassemble I may add an easily accessible 200lb Neodymium 40mm x 20mm magnet.  That should fit perfectly on a 1-1/2" plug.  I probably use a full port valve on a 1-1/2" cross so I don't have to drain the boiler to remove the magnet/plug.

Got the idea when I noticed all the magnetic crap that was sticking to my Braun led light.

cross_skier

Turns out neodymium magnets don't work well in high heat environment

EBEBRATT-Ed

@Southboy

I wouldn't mess with a 40 year old boiler. No chemicals for sure. I would drain it once in the summer and and flush any loose material out and that is all. Clean the gauge glass, service the low water cutoff , pressure control and pigtail etc clean the fire side and service the burner. Run the boiler to make steam to drive the oxygen out of the water

That's it. You put any chemicals in a 40 year old boiler your looking for trouble

ethicalpaul

cross_skier said:

Turns out neodymium magnets don't work well in high heat environment

I'll look for more on this but I find the stated limit in the article below of 212 degrees to be highly coincidental and suspect. 212 is nowhere near "high heat" for any industrial definition (correct me if I'm wrong in this thinking).

https://buntingmagnetics.com/industry-blog/how-much-heat-can-rare-earth-magnets-take/

I'm sure they would be fine in our boilers which top out near 212 (hopefully very near or you're running too much pressure).

Or just go with a regular magnet, they have been used in "dirt collectors" for many decades I believe.

Hap_Hazzard

cross_skier said:

Turns out neodymium magnets don't work well in high heat environment

They don't much care for wet environments either.

These were encapsulated in epoxy, but the water still got through.

In case you didn't know, Neodymium magnets are mostly iron with Nd and Boron thrown in to form tetragonal crystals with some interesting magnetic properties. The shiny appearance is from nickel plating.

cross_skier

I was looking at the epoxy coated ones.  At $10/each for a 200lb one I could pop in a new one every season

cross_skier

Found Neodymium Arc Motor Magnet Rare Earth N33uH Ultra High Heat ones on eBay.  They are DC motor magnets rated for 200C

Hap_Hazzard

You'd have to pop in a new one every season. By the end of the season, it'll be gone!

I'm not really sure what you're after anyway. You want to collect all the magnetite sludge that forms in the boiler and keep it from flushing out when you open the drain cock? I'd think you'd want to flush it out along with all the nonmagnetic oxides.

I'd think you'd probably find out that it's not really a good idea to magnetize the boiler, but that's just speculation. Go ahead and try it and let me know what happens.

Here's a thought: why don't you drain a bucket of muck from the bottom of your boiler, drop a Nd magnet into it, then fish it out and see if you get anything like you were expecting.