New to forum - Help testing boiler water

Quote: Originally posted by ChrisJ

Thanks for responding! It definitely helps some and you have me curious. If sodium metasilicate has such negative effects, do you have an idea of why it's used in steam boiler water treatment? I'm really curious why all of the things I listed are in the product.

Quote: Originally posted by No Tears Only Dreams Now

Quote: Originally posted by ChrisJ   Thanks for responding! It definitely helps some and you have me curious. If sodium metasilicate has such negative effects, do you have an idea of why it's used in steam boiler water treatment? I'm really curious why all of the things I listed are in the product. Here's good old wikipedia to save the day again: http://en.wikipedia.org/wiki/Sodium_silicate#Water_treatment You should use it for the other substances to see why they might be used. I'm not entirely sure why a flocculant would be necessary in a boiler here, maybe it's a general water treatment product? But given the fact that the proportion of sodium silicate is fairly low, I wouldn't say that this specific compound is a major source of your problems, but I could be wrong.

Quote: Originally posted by macckone

Sodium Nitrite is a corrosion inhibitor. Citric acid is to remove scale. Sodium Triphosphate is a detergent commonly used on steel to help remove rust and is acidic. Sodium metasilicate is used as a defloculant. Both sodium triphosphate and sodium metasilicate can cause foaming which is bad in a boiler system. The blue to purple color change suggests a pH indicator. Before boiling the calcium carbonate load of the water will be high but it is forced out of solution by boiling. It is one of the relatively few compounds that is less soluble at high temperature. Citric acid will dissolve most metal oxides and carbonates. The sodium nitrite will also lowers oxide levels which is important in protecting steel. Sodium Triphosphate is an acidic form which binds with calcium as well as iron oxide. This helps remove rust but can cause foaming. Sodium metasilicate is used to settle out particles in the system which should be removed during blowout. It can also cause foaming. Larger systems have a treatment tank followed by a filter before the boiler. They also have deaerators. Things to remember in a boiler system. Carbon Dioxide and Oxygen in the system is bad. Too high of an alkalinity means too much dissolved calcium carbonate. Feed water to the boiler should be deionized or demineralized with the later being more common. Additionally the feedwater should be deaerated. Most of this is difficult for a home system but normal maintenance for a commercial system.

Quote: Originally posted by ChrisJ

Where does the calcium carbonate come from?

Quote: Originally posted by aga

Fatty stuff will always float on water, if it is less dense. Stuff that falls out of the water as a solid is called a Precipitate. If you have a mix of stuff in water that forms a precipitate, then something(s) reacted to create new chemical structures. Exceptions are things like very fine particles suspended in the water, which normally remain suspended in the water due to their very low weight. A Flocculant, such as Sodium Metasilicate, basically makes those particles stick together, making the combined mass big enough to make it fall out of the water.

Quote: Originally posted by No Tears Only Dreams Now

I'd like to caution the notion that calcium carbonate is the factor causing the alkalinity; ChrisJ mentioned that the pH was 11, which is far too high for calcium carbonate to be causing it(pH 9), especially given that it is virtually insoluble in the first place. Solutions of sodium metasilicate are always basic unless acidified, so it could be a contributing factor. Citric acid will not be performing as an acid in these highly basic conditions, rather it will be present as various dissolved citrate salts, which may precipitate insoluble citrate complexes? No idea. And aga, if limestone was composed of calcium oxide, your skin might start to bubble when you touch it. Limestone is calcium CARBONATe, generally.

Quote: Originally posted by macckone

Alkalinity is not the same as pH. Alkalinity is a measure of ions in solution that will react with acid to neutralize it. pH is the actual amount of H+ ions in solution. Based on the information provided the alkalinity is probably ok as is the pH. Citrates are generally soluble salts.

Quote: Originally posted by feacetech

measure P2 alaklinity by adding BaCl (in excess) and phenolphthalein and titrating (this will tell you how much caustic you have in the boiler). Three types of alaklinity P1 P2 and total. Not sure why the high pH is causing carry over, if fat is getting back through with the condensate this can cause foaming and carry over if not total boiler shut down to due to high and low level alarms from soap formation. Your chemicals seem odd and I guess is they are an easy one step treament that wont fit all applications. How are you dosing the boiler dose pot or pumps? Measure your condensate return if you have any (tds, turbity). Meaure the TDS (condcutivity) of the boiler and the feed then you can estimate cycles. Also measure phosphate levels (since you are using a phosphate treatment). Too much can be just as bad as none. You are using a sulfite as an oxygen scavenger you can get test strips that measure sulfite levels(like pH paper (Merk make them) the pink colour of your water might be a problem they go pink the more sulfite you add). Are you pretreating the the feed water (softner or demin)? Are you preheating the water before it goes into the boiler to help drive off oxygen. Qulaity of your raw water will determine the best treatment, measure total harndess, TDS, pH, silica. Then if you run a pretreatment measure your feed water conductivity, hardness and silica. By the look if it you are runnign a phosphate programe so you probably have little in the way of pretreatment. You are trying to do a couple of things in the boiler. Remove the carbonate (to prevent scale build up on hot surfaces) as a mobile serpentine phosphate sludge and thus blow it out of the boiler via bottom blowdown. You are trying to remove all dissolved oxygen to prevent corrosion having a sulfite reserve in the boiler would mean that all oxygen is scavenged. You are keeping the pH high to avoid silica scale and also encourage the formation of magnitite in the boiler to help prevent corrosion (silica scale is by far the worse type of scale very hard to remove). If silca is very high it can carry over (bad block heat exchangers etc). TDS and cycles is key to running a good boiler (15-20 cycles). The lower the better if you have a dirty scaly boiler. Sodium lignosulfonate is good for dirty boilers. Sodium erythorbate is good for metal passivation and oxygen scavenging in conjunction with a sulfite. Are you worried about condensate corrosion and can you add a volatile/filming amine? Not if its a food application. I could be wrong, and you are using high quality feed water and are running a chelation programe(The cirtic acid!)? What sort of boiler is it, fire tube or water tube? Carbonate has retrograde solubility (is less soluable in hot water) so it sticks to the hot surfaces of your boiler, plus it is a good insulator so you loss efficency in your boiler, also it can cause under deposit corrison, worse case is your firetube may warp if its a firetube boiler (metal gets very hot because its insulated by concrete). To much caustic can cause caustic embrittlement of the metal over time. I would be very carfull about using citric acid in your boiler, over use will eat your boiler up plus remove any good coatings you have formed. If you have no pre treamnet and a typical raw water (~100 tds, some carbonate hardness, not much silica, low cholride, normal pH 6-8) I would get a water softner and run a phosphate programe just in case you get slipage or your softner fails. Phosphate additive, caustic and a sludge modifier. Plus a sulfite and a vitamin c analouge in the feed. (the more preheat the less sulfite you will need). Alkaline tanins can work if its not food related in application. run a sulfite reserve of 10-30ppm. P2 alk of 300-600ppm. Phosphate depends on the additive about 20-50ppm depedning on the type. pH 10.5-12, I think 11.2 is the magic number. 20 cycles max, by the sound of it your boiler doesnt work hard and has low cycles anyway? (unless you have good feed water low tds). [Edited on 8-1-2015 by feacetech]

Wow, feacetech you just went so far over my head I can't even see you.

This is a home heating steam boiler. It's not a tube boiler but rather what I believe is called a pin type where it's just a cast iron block with passages through the water lined with stubs.

I just happen to be very anal and learned very fast that raw water wasn't a good idea. I use around 1/2 gallon of water per month and do not have an autofeeder. I manually feed while the burner is firing and when I know it will boil the fresh water for a while. The high PH causing foaming was an assumption I had made based on what I had been told in the past but this could easily be false. That's why I'm here, to learn the right way to do things and understand why I'm doing them. I'd like to talk more if possible? Is there another way to contact you?

I've attached two pictures of the boiler from when I was installing it back in 2011.

More pictures of the project can be found at this URL
https://picasaweb.google.com/thetube0a3/Boiler?authkey=Gv1sR...



[Edited on 1-9-2015 by ChrisJ]

[Edited on 1-9-2015 by ChrisJ]

Quote: Originally posted by aga

Quote: I'd like to talk more if possible? Keep it Public and open : we all learn more that way !

Oh, alright.

By the way, thank you for your PH explanation. It was helpful.

Quote: Originally posted by feacetech

So you add make up water manually? If so losses must be really low? You could fill with DI water (deionised water you can get filters that do this TDS should be close to zero), boil b4 you put it in to de-aerate it, add some tablets at required dose and you should be all good. Check you TDS before you put it in (if you have a conductivity meter then you can estimate cycles). the only real way to get stuff out of the system is from blow down if you have no losses. Steam losses will increase your TDS (total dissolved solids) and therefore your treatment chemicals and unwanted dissolved ions. If its closed loop it shouldn't need much blow down or make up. That we tap on the side looks like a blow down or is it a sample port (or both lol)? Does it have automatic blow down, manual bottom blow down or none apart from sample port/manual side blowdown? I was picturing a larger fir tube boiler for a large scale home brew:p. Is it a steam generator or a hot water boiler? this is important to determine what sort of treatment you want. Not sure what's on the consumer market for these sort of things, but your choice should be dependent on your feed water quality. The better the quality the more fancy treatment you can try and succeed with and have nice efficient long lasting boiler (like your tablets). If its a closed loop hot water boiler find a cheap industrial treatment with Alk and tannins and some phosphate and you should be good. Tannin is cheap and long lasting and good for some one who doesn't want too much effort. There's a test for tannins it involves some KMnO4 tablets and is very easy. Catalysed sulphite is very fast at oxygen scavenging and good. What are the tablets and what are the recommended parameters for the treatment? You can get phosphate test strips and sulphite test strips as well Since its small and probably delicate you want to go for the highest quality feed water with the best treatment IMHO. It should be spotless on the inside and a nice gunmetal grey if done right. Also when I was talking cycles I meant cycles of concentration basically how much more times concentrated you water is vs feed. You can estimate this by (TDS of system)/(TDS of Feed water). If it is in fact a steam boiler for best results you want to have a low TDS treatment and make up with high quality feed water (very low TDS). Think of it like this if you have high grade feed water you just have to worry about minute impurities (Chelation) and concentrate on corrosion (oxygen-scavenger and pre heating if you don't what to waste chemicals) and metal passivation instead. [Edited on 9-1-2015 by feacetech]

I try to keep my losses to a minimum, typically 1/2 gallon of water per month if it's fairly cold out.

This is a steam boiler and my feed water is city water with a typical PH of 7 and TDS is usually around 250 ppm if memory serves. I just checked the boiler's TDS on the weekend and had 512.

The tap on the side is known by the manufacturer as "the boiler drain". Sadly, home heating boilers like this don't get much attention from their owners and most don't even know what a blow down is. They also often rely on autofeeders which almost always add water right before the boiler shuts down and most don't even keep track of how much is added.

We bought this house in 2011 and the previous owner rotted two boilers out in 8 years due to leaks and low PH. From the short time I saw the leaking boiler work I'd say it was taking in a gallon or more of fresh water per day and no one cared because an autofeeder was doing it.

My return water has a TDS of between 1 and 2 ppm which I understand means the steam I am producing is very dry vs the boiler's 500+ ppm.

Before I started using treatment when I measured the boiler water's PH I found it was around a low 6. I found this surprising as my tap water is pretty much always a 7. My understanding is this takes place due to the water absorbing carbonic acid after condensing in the radiators and trickling back through the system? Again, this is what I had heard from someone 3 years ago so I could be wrong, just like the high PH causing foaming.

Now, as far as the pills I am using they are Rectorseal Steamaster tablets. The problem is, I think their instructions assume a far larger boiler because they want me to use 12 pills based solely on my boiler's output. The issue is, my system only holds 10 gallons of water and even 3 pills causes foaming and carryover. I know quite a few people using these pills and not one of them can go past 2 pills in a home heating system. In fact many can't use over 1 pill.

You're right, these boilers do seem fairly delicate. Sadly, many rott out in 5-10 years due to abuse. No water treatment, no blowdowns, access makeup water added constantly due to leaks etc.

Almost always they rott out just above the water line.

What I can say for the Steamaster tablets is the difference between them and plain water in my system is night and day. Before them my water was always rusty, anytime I drained water it was dark brown, nasty and rusty. I started using the tablets in 2012 and ever since I never see rust in the gauge glass and when I do a blow down after several months there's practically no rust.

I've attached a picture from 2012 showing what my gauge glass used to look like for the first year I ran the boiler. After using treatment that glass stays practically spotless. After an entire season it will get a slight rust cloud on it, but nothing like before. I try to keep the PH between 9 and 10 but have had a hard time reading the Phydrion tape I have because 9 10 and 11 look almost the same. The purple color isn't helping either.

I do expect some rust as the entire system is open to the atmosphere. Everytime I produce steam it pushes air out of the system and then afterwards more air gets sucked in. That combined with steel piping, cast iron fittings and cast iron radiators means rust. I've also heard distilled water attacks metal more than normal tap water? If that's the case it's surprising how long cast iron radiators last.

My system typically runs at around 1"WC and I try to keep the pressure as low as possible by venting fast. Most systems like this unfortunately run as high as 2 PSI due to slow venting and grossly oversized boilers.


[Edited on 1-9-2015 by ChrisJ]

[Edited on 1-9-2015 by ChrisJ]

[Edited on 1-9-2015 by ChrisJ]

Here are the instructions to the Steamaster tablets.

What's confusing is they say to add four tablets per 100sqft of radiation (I have 392sqft) OR until the water turns violet. They are recommending I use 16 tablets and yet 1 turns the water a light violet color, 2 turns it a darker violet color.

This is why I'm so curious about the color. What is it and how does it work? Adding more only seems to make it darker.

The pills themselves are blue and stay blue even in water. It's either not until it gets hot, or until it dissolves into the water that the color changes.



[Edited on 1-9-2015 by ChrisJ]

Quote: Originally posted by feacetech

I was just editing my post if you want to reread. By the sound of it go by colour as it appears to be designed for higher output boilers. when you shut her down for summer slug dose her. Or drain her and pressurise with an inherit gas if you want to be nerdy. halfway through he winter follow the slug dose cleaning treatment if you are worried about build up. over dosing can actuality eat your boiler since it contains citric acid as well. nowhere near as much as oxygen though. Im not sure how the indicator works but it my not be linked to the sulphite which you want to use for oxygen scavenging. Then again it may be. If the boiler water loses the violet colour you may have to add a little more over time. this may be a better product they also have one with anti foam surgex http://www.rectorseal.com/index.php/8-way/ they are not very forthcoming with design of treatment in there PDS i.e. hard, soft or di water [Edited on 9-1-2015 by feacetech] [Edited on 9-1-2015 by feacetech]

Quote: Originally posted by aga

Assuming that the Colour is a pH indicator of some kind, grind up a bit of a tablet and dissolve it in water. Add a small amount of vinegar (= an acid) and see if it changes colour. Then add some ammonia (=a base) and see if it changes back. For the Nerdy Air Purge, use an old 5 gallon bottle, a bit of pipe, vinegar & sodium bicarbonate to make a Carbon Dioxide generator. Remember that humans can't live in a CO2 atmosphere, so take care !

Quote: Originally posted by feacetech

it could also be linked to a phosphate or sulphite If its linked to pH there's a good chance that your sulphite levels could drop off over time Do you have a sulphite test kit/ strips

Quote: Originally posted by ChrisJ

I'm assuming I could add small amounts to a pot of boiling water until it's violet and then add some vinegar to see if it changes and if so, add more of a tablet to see if I can bring it back to violet?

One other thing

does your sight glass have a blow down

you can use that to blow down floating solids since it takes water from higher in the boiler

its important to blow down sight glasses (on larger boilers) as they can become blocked.


shut glass steam valve blow out with bottom valve open

shut bottom blow out with steam open

repeat 2 or three times

it may not have a blow down on the glass as I cant see a third valve

In industrial boilers over time the gage glass can become thin down the bottom from the hot caustic water

Also you might like this
https://www.youtube.com/watch?v=PsSVfAg1kRg

larger fire tube boiler failure at a school

[Edited on 9-1-2015 by feacetech]

Quote: Originally posted by feacetech

One other thing does your sight glass have a blow down you can use that to blow down floating solids since it takes water from higher in the boiler its important to blow down sight glasses (on larger boilers) as they can become blocked. shut glass steam valve blow out with bottom valve open shut bottom blow out with steam open repeat 2 or three times it may not have a blow down on the glass as I cant see a third valve In industrial boilers over time the gage glass can become thin down the bottom from the hot caustic water Also you might like this https://www.youtube.com/watch?v=PsSVfAg1kRg larger fire tube boiler failure at a school [Edited on 9-1-2015 by feacetech]

The gauge glass used to have a tiny drain you opened using a wrench. I replaced it with a 1/4 turn ball valve.

Also, I have a skim port to remove stuff floating on the surface. The skimmer is the 1 1/2" port with a plug in. I used a brass coupler and brass plug to ensure I could always get it apart easily.

That looks nice, seems like your doing a good job.

I guessing with that valve arrangement you cant do what I said to the sight glass as when you shut the bottom valve you cant purge it with the steam side?

I would get a sulphite test kit to make sure u keep a sulphite reserve. buy some sulphite or catalysed sulphite extra on the side, if your reserves drop.

Read about Hydrazine if you can get your hands on some. it has some bad properties but if handled carefully it might make a nice boiler .

Normal sulphite I think should be >30 ppm (mg/L) but not too much or its a waste

catalysed sulphite 10-30 ppm

Boil your water for some time before you use it as make up, so you don't add unneeded dissolved gasses. Add just the right amount of treatment and make up with that.

Find a volatile steam treatment you can add
and keep an eye on condensate returns pH and TDS

You shouldn't need to DI or soften your water if that treatment is for hard water, good feed water and better treatments are superior however.

Where do you work, does your employer have a larger boiler with chemical treatment, make friends with the boiler man. See what they are doing. If its a decent size I'm sure they could spare a few mils of treatment. You could also look at their test record and see what treatment programme they are running.

Get a log book keep track of stuff

How much water you add(If you don't do any blow down, constantly add water, and know your system volume you can use this to figure out your cycles etc) , tests of water (ideally pH, TDS, sulphite, p2 alk, PO4), condensate (pH, TDS if you worried about steam side corrosion) and when you have flushed and cleaned the system etc. The logs will give you an idea of how long your sulphite is lasting etc. The trouble with an all in one is just what you notice your sulphite is low, every thing else might be still in the sweet spot so you add more and get every thing too concentrated and it starts to foam and carry over small amounts of boiler water or worse. With your Product query ask them what the ideal parameters are for your feed water (soft/hard) max impurities. Ideal boiler water PO4 levels, pH etc.

My guess with a small boiler like that is you wouldn't even need to blow down as annual draining and cleaning should be enough. Do a good job of cleaning, the sludge in the bottom can set like concrete if left to dry.

On/off seasonal operation isn't great for boilers but that's just the way it is.

Judging by the colour it looks like your tablets a pH indicator http://en.wikipedia.org/wiki/Phenolphthalein

If you add Acid (vinegar, sprits of salt, or H2SO4 drain cleaner) it should go from pink to colourless if its Phenolphthalein.

[Edited on 10-1-2015 by feacetech]

Quote: Originally posted by feacetech

That looks nice, seems like your doing a good job. I guessing with that valve arrangement you cant do what I said to the sight glass as when you shut the bottom valve you cant purge it with the steam side? I would get a sulphite test kit to make sure u keep a sulphite reserve. buy some sulphite or catalysed sulphite extra on the side, if your reserves drop. Read about Hydrazine if you can get your hands on some. it has some bad properties but if handled carefully it might make a nice boiler . Normal sulphite I think should be >30 ppm (mg/L) but not too much or its a waste catalysed sulphite 10-30 ppm Boil your water for some time before you use it as make up, so you don't add unneeded dissolved gasses. Add just the right amount of treatment and make up with that. Find a volatile steam treatment you can add and keep an eye on condensate returns pH and TDS You shouldn't need to DI or soften your water if that treatment is for hard water, good feed water and better treatments are superior however. Where do you work, does your employer have a larger boiler with chemical treatment, make friends with the boiler man. See what they are doing. If its a decent size I'm sure they could spare a few mils of treatment. You could also look at their test record and see what treatment programme they are running. Get a log book keep track of stuff How much water you add(If you don't do any blow down, constantly add water, and know your system volume you can use this to figure out your cycles etc) , tests of water (ideally pH, TDS, sulphite, p2 alk, PO4), condensate (pH, TDS if you worried about steam side corrosion) and when you have flushed and cleaned the system etc. The logs will give you an idea of how long your sulphite is lasting etc. The trouble with an all in one is just what you notice your sulphite is low, every thing else might be still in the sweet spot so you add more and get every thing too concentrated and it starts to foam and carry over small amounts of boiler water or worse. With your Product query ask them what the ideal parameters are for your feed water (soft/hard) max impurities. Ideal boiler water PO4 levels, pH etc. My guess with a small boiler like that is you wouldn't even need to blow down as annual draining and cleaning should be enough. Do a good job of cleaning, the sludge in the bottom can set like concrete if left to dry. On/off seasonal operation isn't great for boilers but that's just the way it is. [Edited on 10-1-2015 by feacetech]

Quote: Originally posted by feacetech

You have sulphite in you tablets it is acting as an oxygen scavenger, it reacts with oxygen to form sulphate. 2 Na2SO3 + O2 → 2 Na2SO4 info about oxygen scavengers http://www.subsport.eu/wp-content/uploads/2012/05/alternativ...

Quote: Originally posted by feacetech

However, sodium sulphite isn't in the MSDS to these tablets? 1: Sodium Nitrite. % by weight 44.04 2: Sodium Triphosphate % by weight 23.52 3: Sodium Metasilicate % by weight 1.34 4: Citric Acid. % by weight 3.36 Opps my bad you have nitrite scavenger theses are typically used in hot water closed loop system in the industrial setting Basically works the same way Nitrite to Nitrate, however there must be a reason these are not typically used in higher pressure industrial steam boilers. You can get nitrite test strips too. http://www.accepta.com/water-treatment-chemicals-wastewater-... that might explain why you have nitrite instead of sulfite [Edited on 10-1-2015 by feacetech] [Edited on 10-1-2015 by feacetech]

Quote: Originally posted by feacetech

do the pH test first its most likely a pH indicator off the top of my head im not sure what level of nitrite is good I think it was higher than sulphite I think cold water I use to look for 50-100 don't quote that though you will have to query from the manufacturer a quick look on the net gave me all sorts of answers one was 1000ppm but sometime these guys want you to use more than you need http://www.nucalgon.com/assets/prodlit/3-87.pdf [Edited on 10-1-2015 by feacetech]

Ok so I took a small bit of water I had left over from when I did some maintenance.

The dose didn't seem very high because the color was faint but I figured it was good enough for now.

As soon as I added white vinegar it turned a pale blue color. The issue is I may have added too much vinegar, or, baking soda is not the right choice.

Right now all I have is cloudy blue water, can't get the violet back. I have plenty more water on hand to do further testing.

Did some more tests, apparently baking soda is a joke when it comes to pH?

Best I can tell, the stuff turns purple when the pH is an 8 or 9. At 7 it was still blue and the only way I could test this was backwards so far, kept adding vinegar until it turned blue while checking the pH occasionally.

Adding more of the tablet will bring it back to purple, but it ends up darker as well, I assume due t more of the pH indicator being added?

If I buy some ammonia, will that be what I need to confirm this?


Also took a picture of the tablets in their natural form.

[Edited on 1-10-2015 by ChrisJ]

Quote: Originally posted by aga

... Caustic Soda, aka Sodium Hydroxide = powerful Base. Edit: put the jug on a sheet of White paper - the liquid colour in the photos will be clearer ! [Edited on 10-1-2015 by aga]

Sorry, I didn't see your request before doing this test.

Using ammonia worked. I guess this means it's without a doubt a pH indicator?

The pictures in order are.

Before adding vinegar
After adding vinegar
After adding a little ammonia
After adding more ammonia.

Adding more ammonia made the color more vivid but not darker. I'm curious though, if adding these tablets "until the water turns violet". If you have a low pH, you would have to add more tablets but you would also be adding more of the chemicals that cause foaming. Isn't this a problem?

Quote: Originally posted by feacetech

some of the other all in one treatment suggest that if treatment reserves are low, slowly adding small amounts of treatment over time (weeks) if large slug doses cause foaming. But now you also know that you cant rely on the colour alone Imagine your water was exceptionally Hard, you could quickly consume your phosphate reserves but the alkalinity of your system maybe fine, you may get caught thinking all is pink no worries! [Edited on 10-1-2015 by feacetech]

Quote: Originally posted by feacetech

technically its a better metal passivator. It will consume some oxygen but nothing like a dedicated oxygen scavenger it will be consumed by metal in the system and some O2

Quote: Originally posted by gdflp

I haven't been keeping up with this thread, so I can't answer your question, but sodium nitrite from the same seller can be found directly on their website at a slightly lower cost here. I've ordered from Duda Diesel multiple times and never had an issue.

Quote: Originally posted by feacetech

I would add sodium sulphite as well as your tablets. Unlike Nirtite Sulphite only scvanges oxygen, but it does a better job reacts much faster the downside being no metal passivation. If you can find catalysed sulphite that would be better, it increases the reaction rate signifcantly. if you cant get catalysed sulphite i would run a reserve of 30-50 ppm sulphite. this maybe difficult to maintain in a small system testing would be the only way to get an idea of how much to add and how fast it is consumed. be aware sulphite will rasie tds and once you reach 2000 ppm (conductivty in uS/cm * 2/3) i would blow down and make up untill it got lower. This wont be as bad as the TDS from the concentrated water but its good to keep it down. Remeber if you pre boil (10-15mins) and treat your makeup before adding this will help. I would find out from the supplier what ideal nitrite levels are, also monitor these levels. I would consider changing treatment if you have steam side issues (corrosion, Acidic condensate, Fe in condensate) and find one with a volatile steam treatment included. The makers of your tablets have another product with a steam treament included.

Quote: Originally posted by feacetech

I wouldnt use steam side protection then your helath is more important than some pipes and valves

Quote: Originally posted by feacetech

Yea they are all non volatile. Is ther any way you can stop the venting of steam and the resulting intake of atmosphere when the pressure drops?

Not so much on a single pipe system.
There are some two pipe systems that run in a vacuum, but single pipe you end up with balancing problems

This is a simplified drawing of how my system works.
Of course piping lengths are different as are radiator sizes and I have two separate mains rather than one, but this gives the overall idea of a single pipe steam system.