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Heating boiler chemicals, treatments, & leak-stop: this article describes various chemical additives & treatments used in hot water & steam heating equipment to condition water, prevent corrosion, adjust pH, and to stop boiler leaks.
We list products & product sources, describe boiler chemical properties, and include links to the products' MSDS information. We also discuss & link to additional heating equipment troubleshooting information such as how to find and fix leaks.
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Reader Question: using Leak-Stop in a Hydronic Heating Boiler: how to fix clogged zone valves & air bleeders
2/4/2014 Ray said: [originally posted at ZONE VALVES, HEATING]
Ray, I took a look at the Hercules Boiler Liquid described as stop-leak for warnings about clogging of zone valves or circulators and didn't see any warning. It is significant that at least some of the products I reviewed, including Hercules Boiler Liquid explicitly assert that they do not clog heating systems. Quoting:
Watch out: nevertheless a quick search for "boiler leak stopper clogging" will indeed disclose some complaints by HVAC techs and others who cite occasional problems with clogged check valves, boiler drains, and other components following boiler stop-leak products. Typically the complaints I found did not name the product used.
Steps in Un-Clogging your Stop-Leak Clogged Boiler [suspected cause]
1. If your zone valves have a manual-open position and latch, use that to move the zone valve open - at least you'll have heat, and moving the valve (rarely) might free it up
2. Try (with the heating system cooled down) opening and cleaning a manual air bleeder if that's what you've got; if you've got only the float type air bleeder devices, indeed the bottom opening or float could be stuck. Those are inexpensive devices; I'd remove an old one, allow a small amount of boiler water (ounces) to blow out the mount opening, and install a new one.
3. Depending on where the boiler leak was, is it possible your system is air bound? If so we can point you to diagnosing and fixing that problem.
4. If removal of a boiler component confirms that it was clogged, I would contact the company for advice. But before calling them, review the product use instructions I quote below - it might save some embarrassment.
Product instructions for the Hercules boiler liquid you used are quoted from the company's information
Boiler Leak-Stop Product Sources
I list Hercules boiler liquid stop leak first because it's the product used by the reader above and because it's widely available at heating suppliers and from other sources. A common ingredient in many of the boiler stop-leak products listed below is sodium silicate. Some products contain additional or alternative chemicals and sealants.
Im a journeyman plumber and I know how to braze but I'm not sure how to go about repairing a pinhole leak in a copper hot water baseboard heater. Obviously it has to be dry before I can braze it but how do I drain it and once repaired how do I properly fill it up with water and bleed the excess air?
Reply: solder repairs of small leaks in copper heating baseboard piping
The proper repair of a pinhole leak in copper piping would be soldering not brazing. But you'll most likely need to remove the water from the baseboard heater first. Or one can cut out a bad section of tubing or piping and solder in a short section with unions and copper piping of the same diameter. Be sure to properly sand and prep the copper pipe surfaces, remove any burs, and use a soldering paste or flux to assure a good solder connection.
Watch out: often the presence of a single pinhole leak is an indicator of more trouble ahead. Corrosion, or too-thin or defective copper piping may be prone to developing multiple leaks. I'd go ahead and patch or repair the present leak, but I'd keep an eye on the building heating distribution piping and baseboards for more leaks down the road.
Josh asked: I have an old one pipe steam radiator that has a small crack about 8 inches up. It drips a bit but my concern is the steam. Is this dangerous to have expelled into the air as far as breathing quality. I am not sure If it is a health issue. I have some concerns about having It replaced with a cheap one from china. Thanks so much for your help. - Josh (also by email) J.F. Thank you so much for your help.
R said: Today at work, a few pipes and radiators blew in some of the rooms. The leak and steam got so bad you could hardly see your hand held out in front of your face. I was in there for a while trying to find the shut off for the water and keeping the water from leaking out into the hall. I was breathing all that steam in for quite some time and I was wondering if there is anything I should be worried about. My lungs and eyes were a little irritated, but I am wondering if there could be something more. - R. 1/30/2014
That said, here are some things to consider:
Follow-up comment: Harmful chemicals in steam from steam boilers?
Thanks for the quick reply Daniel. I was unsure if chemicals were commonly used in the w
Reply to R about steam radiator leaks & chemical exposure:
While residential and most commercial steam systems operate at very low pressure - under 1 psi, there are some commercial systems that work at higher numbers - where an actual explosion would be potentially dangerous.
List of common chemicals found in steam boiler water treatment compounds and reference to their MSDS information
For an explanation of pH and its importance see WELL DISINFECTANT pH ADJUSTMENT
Carbonic acid (H2CO3) formation in heating boilers
Carbonic acid (H2CO3) formation in heating boilers and the resultant need for boiler water treatment:
Carbonic acid (H2CO3) build-up in hot water heating systems can occur in areas where the pH of your boiler water is below 8.5 or where other heating system malfunctions cause this inorganic corrosive acid to accumulate in hot water piping.
High carbonic acid, like excessive oxygen levels in heating water, can lead to hot water piping leaks, water damage, and loss of heat in the building. In a steam heating system, condensing steam dissolves carbon dioxide (CO2) to form carbonic acid that in turn corrodes piping.
Ask your heating technician if your boiler water needs treatment or if your system needs additional venting equipment to remove excessive gases from the heating water.
Treatment chemicals for acidic boiler water may include lime and soda ash (COH), phosphate, chelates, oxygen scavengers, neutralizing amines, or filming amines, all designed to protect the heating system boiler and piping from acidic corrosion.
Check with your boiler service company and take a look at the boiler service tag - let me know if any additives were used in your system (unlikely in residential steam boilers) and we can research further by reviewing the MSDS for those products.
Corrosive liquids used in some treatment compounds are skin, lung, and eye irritants (and considered unlikely to be ingested), but you would not expect to find these being released at harmful levels into occupied space from a steam radiator steam leak, since the same steam is also vented quite normally through steam radiator vents during normal system operation.
Try JB-Weld Epoxy for Cracked Home Heating Radiator Repairs?
Some readers have reported and we consider that it may be possible to repair a small crack or leak in a cast iron radiator using an epoxy product.
One source to consider (we have not tried this) is JB-Weld, a producer of a range of epoxy and sealant products sold most readily in automotive supply stores and some building supply stores. email@example.com.
However if the radiator leak or crack is not in a location at which you can thoroughly clean and prep the surface, we're doubtful about this approach.
For repairing leaks in cisterns see CAULKS, NONTOXIC or select a topic from the More Reading links shown below.
Continue reading at BOILER LEAKS CORROSION STAINS or select a topic from the More Reading links shown below.
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