Soft water and Boiler

Bryan_5

Was just poking around the Burnahm Site looking at the boilers they have and in the installation manual something caught my eye. It said not to use softend water in a boiler.
I just had a softener put in last fall. They never mentioned that there would be a problem. Not that I expected them to. So I have 2 questions. Is it bad to have that water softend?
If so do you beleive I may have caused myself some problems by going a whole heating season this way? Your response is appreciated. Let me know if I need to repipe the water.
Thanks
Bryan

hot_rod

lesser of two evils?

Is this a hot water or steam boiler. Generally on a hot water system the boiler is filled once, maybe twice if the system is flushed. This amount of softened water, in my opinion, should not compromise the sections.

I guess you would have to weigh that against how hard or how bad the unsoftened water would be in the systems. Often times around here new wells are extremely hard, lots of turbity, iron and silt. You really need to test the water before the softner to decide which is the better "fill" water.

Worse case, I import water for the boiler fill. I always add inhibitor chemicals that buffer hardness and ph, should the local water not meet spec.

I would REALLY like to see boiler manufactures "beef up" the cleaning and fill water procedures for new boilers, in their installation manuals. This should include proper cleaning methods and a selection of products, as well as some guidelines for what constitutes acceptable water quality.

It should also encourage ocassional water testing after installation. The modern radiant piping products may in fact be adding to the issues that cause premature HX failures, from what I have seen. This is especially true in the case of manufactures that still promote non barrier tube, for cost cutting reasons, in hydronic applications. I think you would be surprised on how often this happens


Water quality is critical in low mass copper, aluminum, and stainless boilers, but can also greatly effect cast iron boilers and the ability of the heat exchanges to operate efficiently.

hot rod

Bryan_5

Hot Rod,
Thanks for your response. Sorry for not giving more info. My system is a 2 pipe vapor system. Before they installed the softner the ph tested fine. around 7.5 The water is very hard. Had a rating of 20 for the hardness. So not sure which way is best. My boiler is still in good shape but its got to be atleast 20 years old I really dont know the exact age. Only been in the house a short time.

Unknown

Bryan

Regarding the use of softened water in a boiler, I offer the following explanation. Field testing has shown that the prolonged use of softened water in a cast iron boiler can accelerate the possibility of internal corrosion of the iron inside the sections by oxygenated water. Normal water contains minerals that help to form a protective skin of sorts on the internal surfaces of the boiler. If makeup water is continuosly added to a boiler, which is the case with a steam boiler, then the risk of oxygenated water is prevalent. In a hot water boiler, the risk is still there if a small, undetected leak should form somewhere in the system.

As far as your concern of any harm being done in the one year period the boiler has already seen, I would doubt that any harm has occured. I would, however, advise having the piping changed so that untreated water is used instead. Most installers will pipe the outside sillcocks of the house to untreated water. This would be the place to connect it in. Hope this helps.

Glenn Stanton

Manager of Training - Northeastern Region

Burnham Hydronics

Bryan_5

Glen,
Thats what I thought. We did have a the kitchen and outside water piped so it was unsoftend, so it wont be a big deal to change it over. I am just glad I read that on your site. I never even gave it much thought. Thanks for your help.
Bryan

hot_rod

Glenn, Im not clear

on you statement

"Field testing has shown that the prolonged use of softened water in a cast iron boiler can accelerate the possibility of internal corrosion of the iron inside the sections by oxygenated water."

Seems to me it is very important that the installer or owner monitor the boiler system to know if there is a small leak requiring make up water. Even a tiny leak requiring makeup water will seriously damage any boiler HX. On my systems I recommend the fill water be left off and a LWC device be installed to protect the boiler, and notify the owner of a potential leak.

Does Burnham recommend leaving the fill valves on at all times? seems this is the only way a system would refill, regardless of a small leak?

hot rod

Unknown

Hot Rod

That kind of goes without saying on a hot water or steam system. Monitoring water usage is important with any boiler system. As far as leaving the pressure reducing valve on or off on a hot water system, we don't advise. This has been a much disputed and contraversial subject here on the wall and at meetings I have put on. One manufacturer of these devices says to shut them off after initial static fill and another does not. I like to say that if you are incorporating a low water cutoff on the hot water system, then shut the water supply off, even though it will probably not fill anyway if an overheating condition develops due to elevated pressures and temperatures within the boiler and the possibility of flashing to steam occuring. Hope this helps.

Glenn

Tony Conner

I Suspect That...

...a lot of manufacturers worry that many, if not most people (including a very large percentage of contractors) don't understand water treatment chemistry very well. There are a lot of folks who think that if they have a softener on the boiler system, they're "bullet proof". All a softener does, is soften the make-up water, to prevent scale, period. It doesn't do anything else, such as dealing with dissolved oxygen.

If you have so much make-up in a hot water or steam straight heating system that you need to consider a water softener, you have bigger, mechanical problems to deal with. If for no other reason, think of it in terms of fuel used. Instead of, say 140*F water coming back to your boiler, you've got make-up water out of the municipal system at 40*F. You've lost 100 BTU for every lb of water you didn't get back. If you're running 80% boiler eff, you need to burn 125 BTUs of fuel just to get that lb of water back to it's normal return temp. Then add in all of the scale and corrosion. Ugly. And the colder the water, the more dissolved oxygen it'll hold.

Make-up water is pretty much the root of all water treatment/chemical evil in heating systems.

Dave (Canada)

Hello guys
I have a new WM go3 boiler with LWC and the make up water is piped to come from the hot side on my EHW tank,
Is there a problem with using make up water from my EHW tank
There are 2 small leaks in the black iron fittings and it does not seem like they will be a bother until the heating season ends, then I will tear them apart to correct the problem.
Thanks
Dave

steve_6

posting

dave, place your posting on a new thread. you'll probably get a better response, rather than hidden
in someone elses posting. steve

George_10

soft water

Another thing to consider is the amount of chlorides that softened water contains. That is one of the culprits that causes corrosion. The amount of dissolved oxygen in the water is directly related to the temperature of that water and not necessarily due to the softner.

A softner is paramount when a steam boiler is in use. If you are dealing with a closed loop heating boiler a softner can cause excellerated corrosion. If your make-up water has a high concentration of CaCo3 (calcium carbonate) above 100ppm then the prudent thing to use would be DI water or distilled water to fill the system. This removes the calcium and other minerals with out leaving high residuals of chlorides.

Scott

Mad Russian

Hi, Guys! It's amazing how the best people in the industry spend their precious time. The discussion isn't worth the time spent typing. There is expression in Russian: to catch the fleas,that's exactly what we are doing.
There is no difference between steam and water heating system, concerning make up water: they are both closed systems and the amount of replaced water is very negligible even if you drain it every year. In that aspect there is no difference between hard and soft water. Softened water doesn't contain any more oxygen or chlorine than hard water.
Mr Bryan! That problem distracts your attention from the 20 year old boiler itself. It probably works at around 30% efficiency (see my coming article in May issue of "Fuel Oil News".)

Steamhead

Not All Older Boilers are Over The Hill

I have a 20-years-young Burnham that still runs at its peak efficiency (AFUE 82%, combustion efficiency 85-86%). Of course, it has been well taken care of.

If you think about how a steam system works, you'll see why it's different from hot-water. Steam heating systems are open to the atmosphere thru their air vents. Over time, some water will evaporate and be expelled with the air on the next start-up. On hot-water systems the vents remain closed unless air accumulates, at which time it is vented manually or automatically. There is no evaporation loss in hot-water.

Yes, the best and brightest in hydronics are right here on the Wall. Time spent here is always well-spent!

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