Water chemsitry for new high efficiency boiler


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Old 08-23-12, 09:01 AM
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Water chemsitry for new high efficiency boiler

I recently purchased and had installed a new Munchkin MC-80 high efficiency (~95%) boiler for my home. The manual for the boiler mentions to have specific ranges for the water used inside the hydronic closed loop, otherwise I risk "heater failure due to improper water chemistry that is not covered by the warranty". The total volume in my closed loop is about 54 gallons of water.
Based on performing a water quality test on my tap water, I'm considerably above the water hardness level. My water hardness is at 21 grains of hardness while the boiler manual mentions it should be less than 7 grains. I also have twice the sodium level that is mentioned in the manual.

My first hunch is to dilute/titrate the tap water with distilled water until I'm within the adequate levels. For my 54 gallons, I will need about 16 gallons of distilled water to cut the hardness level by a third. Yet to reduce my sodium level I will need to increase that to 27 gallons of distilled water to cut the current value in half.

Is this a DIY type of thing or are there HVAC companies that perform the service of filling your hydronic lines with water that is of the correct chemistry? I figure it might beneficial to also add propylene glycol to inhibit the water from attacking metal components as mentioned in the manual.

Thanks for your replies in advance,
-George
 
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Old 08-28-12, 05:00 PM
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Sorry you bought something where the manufacturer is so darned picky about water quality. If it were a steamer, that's one thing but hot water??? They act like the water is going to be constantly replaced.
I know of no contractor who is going to do much more than add some boiler water treatment chemical. They might test your water for pH, maybe hardness, but not sodium or anything else much less add distilled water to get the tap water within some boiler manufacturer's pipe dream specs.
 
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Old 08-29-12, 04:34 AM
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I think their requiring that specific type and testing of water is only so they can claim the percentage of efficiency. When you call and complain that it's not 95%, they can turn around and blame it on the water.

As Grady had mentioned, ph level and hardness is about all that is really accounted for.
 
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Old 08-29-12, 07:37 AM
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Thanks for your replies! The contractor just filled it with city water and didn't even mention the picky water requirements.

The boiler has a stainless steel interior, so its pretty hardy. I was thinking of adding a water softener to decrease the hardness, but then that will increase the sodium level. pH would be very hard to control since distilled water is acidic (pH 5.8-7), so you need to titrate with baking soda or ammonia to raise the pH. All pretty complicated.
 
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Old 08-29-12, 08:08 AM
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And all that would change over time.
If you saw the junk I drained out of my boiler pipe work when I had to change the circulation pump... The previous owner never bothered to maintain the well water treatment gear.
 
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Old 08-29-12, 09:18 AM
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In my opinion, stainless steel is not a good material for a closed hot-water heating system. It is subject to stress corrosion cracking and other problems. Carbon steel or cast iron would be better, along with effective air elimination.
 
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Old 08-29-12, 09:36 AM
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In my opinion, stainless steel is not a good material for a closed hot-water heating system. It is subject to stress corrosion cracking and other problems. Carbon steel or cast iron would be better, along with effective air elimination.
I've only ever seen copper and PEX for the pipe work on a hot water system. I believe my boiler's internals are cast however.
 
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Old 08-29-12, 10:32 AM
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I've only ever seen copper and PEX for the pipe work on a hot water system.
Threaded black steel pipe is widely used and works fine. If PEX is used, it must be the type with an oxygen barrier.
 
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Old 08-29-12, 10:40 AM
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I think adding distilled water is a bit silly. How were you planning to add it? And there are many disadvantages to adding glycol.

It would be much more realistic to install a small reverse-osmosis unit to the water make-up/fill line of the boiler. Either that or tell the guy who sold you the Munchkin boiler (and filled it with tap water) to come back, rip it out, and replace it with something more practical.
 
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Old 08-29-12, 05:42 PM
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I suspect the reason they are so interested in sodium is the most common source of chlorides, which are hard on stainless, is sodium chloride.

Regarding the water softener: You could use potassium chloride instead of sodium chloride for the salt. Potassium chloride is considerably more expensive & not normally available at your local big box store, but it does work & is sometimes specified by doctors for their patients who have high blood pressure & use a water softener.
 
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Old 08-30-12, 08:16 AM
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gilmorrie, I've taken the trouble the past week of adding a garden hose bib tee to the supply and return lines of the hydronic system. This has allowed to flush the system of any sediment and also allows me to use a utility pump and fill the system with distilled water if so necessary for the new boiler. I've already flushed the system and the water coming out looks disgusting. Black in color at times and then bright orange in color (likely from the iron oxide flakes in the water).

Adding a reverse osmosis filtration system on the make-up/fill line would of been simpler than adding the piping tees and pump. But at least those tees were useful in flushing the system. Also I suspect the RO membrane will get very fouled based on the high hardness (20 grains) of my city water.

Grady, your suspicion s right about the chlorides being hard on stainless since they also have a 200ppm limit on the chloride concentration.
 
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Old 01-18-13, 09:04 PM
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While this thread aimed at "water chemistry... for high efficiency boilers" has been dormant for the past 18 months... If anyone is still here I would appreciate similar "water chemistry" guidance for old cast iron domestic heating boilers...

By no means would I attempt to high-jack a discussion thread! Simply that the superior chemical knowledge required for contributors dealing with high-efficiency systems would be a gold-mine of information to those of us wanting to simply prolong the life expectancy of old, domestic hot water boilers (e.g. NatGas, baseboards, 20 yrs old). For context, the common practice of simply filling up the hydronic system with city water anywhere seems misguided; on the other hand, demineralized or deionized water is better than distilled water (which can be acidic), but what about also using inhibitors, periodic testing, methods, etc?

At your discretion I would appreciate personal messages, or a side-post with your suggestions for where else this topic has comprehensive discussion (so far that has eluded me).

Thanks!
 
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Old 01-18-13, 09:22 PM
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"water chemistry" guidance for old cast iron domestic heating boilers...
Fill it up.

Heat it up.

Vent the air.

Fuggeddaboudit!

Seriously, it IS that simple.

Do you think your boiler would still be standing if it weren't?
 
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Old 01-18-13, 10:53 PM
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Re:
"water chemistry" guidance for old cast iron domestic heating boilers...
NJT replied: Do you think your boiler would still be standing if it weren't?
By no means am I looking for extra things to worry about :NO NO NO:, here is my reason for inquiring:

When I changed my boiler's inoperative pressure relief valve today (quote below) there was a gross difference in the water that initially came out of the boiler's drain pipe and what eventually came through through the new relief valve. I mean the initial drain water was completely clear whereas what came out of the new PR valve was fowl and yellow looking; why such drastic difference, where is the yucky water residing in my system?

My humble concern is that city water anywhere comes with a lot of other minerals & stuff (PH & hrdness), where do they go in a cast iron water boiler that simply feeds a home baseboard system?

In other words, aren't there a bunch of untold sediments accumulating in the bottom of the (unattended) domestic boiler working to eventually make it fail? If so, aren't there additives that would dissolve that and could be flushed out periodically to further prolong the reliable life expectancy of a thus-far robust heating system?

Just thinking and hoping for further guidance...

-----
Above referenced quote:
PS- Thanks to your guidance... today I gained enough confidence to plunge in for the very first time to change something in my home boiler system - Success! My boiler's pressure-relief (Watts 374A) would not manually release because it was caked in solidly full of crap. Thanks guys!
http://www.doityourself.com/forum/bo...-do-right.html
 
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Old 01-19-13, 06:21 AM
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You could run a cleaner through the system then fill and add a conditioner. I'm currently doing a flush/cleaning with Hydro Solv 9100 after dumping an initial fill of Glycol. It's been in my system for 4 weeks now and will be purged and flushed this weekend. The fresh fill will get a conditioner added.
 
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Old 01-19-13, 06:44 AM
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Most of the mod cons I installed come with a tube of x100. I put it in but most installers I know just throw the tube out. These are the same installers that pipe these boilers in a conventional layout and have no clue.

From my knoledge of these products this seems to be widly used and the best out there. There is another but I cant recall the name.


Weil mclains come with a tube of it.

Concentrates | Central Heating | Sentinel central heating products.
 
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Old 01-19-13, 07:10 PM
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My humble concern is that city water anywhere comes with a lot of other minerals & stuff (PH & hrdness), where do they go in a cast iron water boiler that simply feeds a home baseboard system?
They ultimately come out of the water and settle wherever they find a comfortable resting place.

The amount of 'stuff' in a single boiler filling won't be enough to cause a problem though. Only when a system is leaky and water needs to be added, a little at a time, day after day, year after year, do problems like this generally arise.

There are ppl who routinely flush and refill their systems yearly, thinking this is GOOD for them...

EHHHHHHHHHHHHHHHHH, WRONG!

It's terribly bad!

aren't there a bunch of untold sediments accumulating in the bottom of the (unattended) domestic boiler working to eventually make it fail?
As you may know, I just replaced my almost 30 year old boiler this year. In order to make easier to move, I split the sections apart. Was very surprised to see almost NO sediment in the bottom of the water jacket... or anywhere inside the boiler.

I think in the 30 years I've lived here that boiler may have been drained (not completely) twice.
 
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Old 01-20-13, 11:45 PM
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Tomf63 wrote
You could run a cleaner through the system then fill and add a conditioner. I'm currently doing a flush/cleaning with Hydro Solv 9100 after dumping an initial fill of Glycol. It's been in my system for 4 weeks now and will be purged and flushed this weekend. The fresh fill will get a conditioner added.
Thank you and others for pointing out common chemical choices, otherwise the myriad of options is mind-boggling! I'll be looking into these.

Next I would appreciate guidance for selecting a pump; I've examined the website for pony pumps ([url=http://little-giantpump.com/]) and found it impossible to navigate. My principal requirement is enough pressure to reach the 20 ft highest point in the pipes that feed my baseboards. My place is only 1,050 SqFt (one zone), thus a very low Gal/min will suffice. My hunch is that I would be better off with a NON-submersible pump, as long as it could suction out of a bucket or similar container - but that's just a hunch.

Any suggestions? Thanks!
 
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Old 01-21-13, 06:08 AM
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Just a small transfer pump will do. You use the boilers circ to fill the system. You need to fill and drain at the same time from both sides of the loop.

The conditioners are usually a paste and just get injected in with a syringe....
 
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Old 01-21-13, 10:18 PM
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You use the boilers circ to fill the system. You need to fill and drain at the same time from both sides of the loop.
Thanks. If I got the concept, the transfer pump would feed (e.g.) the Hydro-Solv 9100 (http://www.rhomarwater.com/media/W-91001.pdf) that tomf63 suggested into the boiler's drain valve while the return is being dumped into a drain. Then, as soon as the Hydro-Therm is in I would first shutoff the return valve, then the boiler drain valve and both pumps. Is that along the right path or am I totally lost? Also, how can I get the circ pump to operate without the thermostat calling for heat. (Would I just turn the boiler to pilot and then turn up the thermostat?)

The conditioners are usually a paste and just get injected in with a syringe....
Hmm, does that mean feeding water from a bucket into the boiler's drain valve and then injecting the paste into that feeding hose?

Sorry to be so thick... so much to learn - Thanks!
 
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Old 01-21-13, 10:59 PM
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How new is the system???

What are you trying to accomplish?

Did you fill the system from city water or well water?

I would just install a inhibitor... You could flush if you like.

Like I said before, the product that comes with the modcons are the sentenial products. I just add X100. They have in an aerosol can. Just screw to the hose bib and pull the pin.

This stuff will protect your boiler. Adjusts PH and is a buffer. Will neutralize the salt/ sodium...etc...

If you want to clean use the x200. Then treat with the X100. Test once a year with the test lit and add x100 when needed.

RAPID-DOSE
 
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Old 01-22-13, 07:15 PM
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Mike, thanks again for pointing me in the right direction for learning about all this stuff. (Might “water treatment for boilers” later be added as a “sticky”?)

For context: As a retired home owner, having only recently joined this forum, what I have learned thus far has given me enough courage to plunge into a hands-on refurbishment of my boiler - thanks!

How new is your system? City water or well water?
In summary, my home consists of two adjacent apartments (1,050 SqFt each) that have been inter-connected into one dwelling, thus I have two separate gas fired boilers – each with a single zone with baseboards. These two 22 year old cast-iron boilers (and about 95% of their installation) are identical and I am nearly done with a complete replacement of all valves, air vents, expansion tanks, etc. Because of all this refurbishment they have recently been refilled with city water.

What are you trying to accomplish?
In broad terms, upon completing said refurbishment I would like to restore the system’s “inside” as best as possible, i.e. remove scale build-up, corrosion and whatever else is appropriate. Then of course to preserve it in that condition, and to use antifreeze due to my winter conditions. The challenge for me is learning what/how to accomplish this, including the subsequently required periodic testing and chemical fine-tuning.

First the chemicals and then the methods for applying them. Using your suggested Sentinel products as a reference (RAPID-DOSE), my first thought would be:
Cleanout - X800 Jetflo Ultimate Cleaner for removing scale & corrosion.
Sentinel “Leak Sealer” to prevent weeping joints, in anticipation that I will be adding antifreeze.
Refill water – Demineralized or deionized water? While this may be considered overkill, after all that refurbishment effort why not go one step further and circumvent city water for the inaugural fill? Would demineralized or deionized water interfere with the function of an LWCO? (I know not to use distilled water because that can have a low/acidic PH.)
Chemical passivation of the internal surfaces - X100 Inhibitor, or is that not necessary if I’m going to use inhibited antifreeze?
Antifreeze – X500 Inhibited Antifreeze (non-toxic PG).
Subsequent testing & maintenance – To be continued…

Regarding methods to apply these chemicals, rather than making this post any longer I’ll skip ahead to my greatest concern for the equipment I’ll be needing once I reach “maintenance mode”. Per your comments, I am glad that for simply adding some X-100 I can use an aerosol can that screws into the hose bib, but my greater concern is maintaining the antifreeze concentration over time. In other words I anticipate that at some point in time I will need to add e.g. half to one gallon, what then? That is when my instinct tells me I would need to feed the antifreeze make-up via a pony-type pump capable of injecting into a 12-15 psi system. If so, what kind of pump should I use? (Suctioning directly from the antifreeze container… priming?... avoid injecting air… etc.)

This DIY forum is the best - Thanks again!
 
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Old 05-29-13, 08:53 PM
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Boiler manufactures are putting requirements in for water hardness (< 7 grains per gallon for Lockinvar, for example), and I'm not sure we should take it lightly. Acidity is maybe a bigger issue. Because these are issues of both boiler metals and local water chemistry, installers in some areas will never see issues, while some areas might have many issues. So, just because a good installer says they've never done anything to fix water quality or never had a problem doesn't mean that that advice is relevant to your water chemistry and boiler.

A trusted old timer I work with some on multifamily installs tells me that he has had a hard time with what he calls 'mud' build up with modcon boilers on some jobs. HX gets gunked up, hot spots develop, and the HX fails. Or gets clogged, and needs frequent cleaning. His solution is to deal with the water chemistry (esp. low pH), and install a bag filter to get the mud out. He described this working on one large job that had had ongoing problems and failed HXs. Now, he looks more closely at the water, and recommends a filter and treatment if it looks bad.

Two interesting points out of this. He told me that he's seen a manufacturer push back on a warranty claim when there is evidence of a lot of crud on the HX and it fails. Second, he said he has had better experience with the downfire fire-tube boilers like Triangle Tube than horizontal fire. Some of the downfire boilers have greater tube size and lower head, so it would make sense that these would do better in a situation where you get scaling or a lot of gunk.

Anyhow, I'm trying to learn more about this issue. If anyone else has anything, please chime in.
 
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Old 05-30-13, 08:44 AM
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The efficiency of a hot-water boiler, e.g., mod-con, should not have anything to do with any required water chemistry additives. It is a closed system, and the circulating water doesn't "know" what the efficiency is.

The only thing important is the materials of construction used in the boiler and the rest of the system. Copper, carbon steel, or cast iron should not require any water treatment additives. The only thing required is an effective air removal device if a bladder-type expansion tank is used. Otherwise, plain tap water is fine and has proved satisfactory for many decades. If there are any iron-based components in the system, the water will immediately turn black - which is normal and not harmful - you can flush it and a week later the water will be black again (and more susceptible to corrosion due to the air introduced when refilling with fresh water loaded with dissolved or entrained air).

If your boiler has stainless steel or aluminum components, then water treatment additives might be called for. But otherwise, I would wonder about what the boiler manufacturer bases any requirement for water treatment.

As far as "mud" found in the system, I wonder what the source of the mud is. If the make-up water is clear, and there are no suspended solids, then the only thing I can think of is dissolved solids that precipitate once in the system, maybe hardness ions. But such dissolved solids can only precipitate once, and couldn't keep building up over time - unless you are frequently refilling the boiler. If you have a water softener, I would use softened water for boiler makeup - but if you have stainless steel or aluminum in the boiler, any chloride ions not fully rinsed after resin regeneration could damage the boiler.

My hot-water boiler system has been in operation for over 60 years. The boiler tubes are carbon steel and the system piping is garden-variety, A-53 black steel. When I have opened the system for maintenance, such as replacing a valve or the pump, the internal wetted surfaces are clean as a hound's tooth, with no evidence of corrosion, buildup, or mud. The water itself is as black as the ace of spades - which might lead somebody to mistakenly suspect the there is mud in the system.
 
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Old 05-30-13, 01:04 PM
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Boiler manufactures are putting requirements in for water hardness (< 7 grains per gallon for Lockinvar, for example), and I'm not sure we should take it lightly.
Anything over 7 gpg is considered hard or very hard water. I think most people with such hardness already have installed a water softener - or else they must put up with persistent trouble bathing, shampooing, shaving, and doing laundry. Well water of such hardness, at least in my area, often is accompanied by high iron content, which, without softening, affects taste and stains toilet bowels. Many cities, even my little berg, soften the water at the city water plant.

I'm unsure of the basis for Lockinvar's requirement, but I think most domestic water supplies would meet it.

Off topic: I once worked at a power plant with very high-pressure, supercritical boilers (3900 psi, 1100 deg F). The quality of the condensate and make-up water had to be extremely pure. The cost of make-up water was, as I recall, maybe several dollars per gallon. On Sundays, when none of the big bosses were around, we would pull our cars into the plant and use pure condensate to wash and rinse the cars. A drop of carwash soap is enough to make a bucket of suds and the cars would rinse off squeaky clean, no chamois required.
 
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Old 06-06-13, 07:02 AM
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Gilmore, I appreciate your comments, but I think things will vary depending on where you are at, and what the water is you are dealing with, and what kind of distribution piping you have. I often work with owners for apartment buildings with 50 or 75 year old iron piping, cast iron radiators, all originally sized for steam or gravity HW. These systems are impossible to flush out, and we do find suspended solids in the water that can gunk up boilers. This is very different than if I were in a 10 year old single family home with fin tube radiation.

This is a DIY forum, so I apologize for being off topic a little. But, how about putting the burden on the contractor. If a manufacturer denies a warranty claim on a heat exchanger b/c of water quality (or workmanship or design), then the contractor is on the hook to uphold the manufacturer warranty and pay for the new heat exchanger.
 
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Old 06-06-13, 06:35 PM
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I like your thought that an installer should be responsible for making sure that the water meets whatever specs apply to the boiler. And, your comments regarding suspended solids in older systems is relevant.

My original comments were directed to the issue of Lockinvar's specifications saying that the make-up water hardness should not be above 7 gpg - my point was that the vast majority of domestic water supplies should meet that, with a water softener, if necessary, for well water or unusually hard city water.

My residential boiler is 60 years old, with cast iron radiators and black steel (not iron) piping. It was originally designed for circulated hot water, not steam or gravity flow. I have seen, so far, no gunking up of suspended solids, etc., and the system has never been routinely flushed. Black water, Yes.
 
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Old 06-06-13, 07:36 PM
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Generally speaking I am against chemical treatment of residential hot water (or steam) heating systems. I take this stand in spite of the fact that I used chemical treatment in the system I installed in my parent's house many decades ago. My reasoning is that I was a professional, I spent more than thirty years working in power plants and chemical treatment of the boiler was as natural as brushing my teeth. Few homeowners will think for two minutes out of the year about their heating systems unless something goes wrong.
 
 

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