Pre heating season maintenance

mygardenshed

First year with the new boiler went very well. My question concerns the recommended time to do a pre heating season skim, flush and fill. I’m thinking as close to start as possible so I can run the boiler to burn off oxidants and not waste fuel ( gas).
Any preferences?

ethicalpaul

There's no reason to do a skim or major flush before a season of heating in my opinion (especially after a brand new install, unless you suspect remaining oils). Just flush a little out of each drain until any "mud" is out, and if you really want to reduce oxygen, refill with boiled water, but that would be pretty over the top.

SteamingatMohawk

The solubility of oxygen in water goes to 0 at 212F. The major source of oxygen in the system is not feed water. It is the constant expelling of air on heating and the returning of "fresh air" when the system cools down and sucks air back in.

Lost Art has a discussion on p. 191-192 on corrosion inside the system . Dan says the real problem is carbonic acid created from carbonates and bicarbonates in the feed water that then reacts to form carbon dioxide, which then creates carbonic acid, H2CO3 during the heating/cooling cycles.

ethicalpaul

But the feed water comes in with lots of oxygen, in fact, water treatment facilities often inject oxygen into the water to make it taste better.

While the feed water may or may not be the major source of oxygen as you allege, I think it's well accepted around here that feed water is the major source of oxygen that leads to corrosion of a boiler.

Otherwise, how could a boiler kept from leaking survive for decades while a leaky one (which then has fresh makeup water added regularly) can rot out in just a few years?

So your first paragraph is confusing to me and I think somewhat misleading, if we are talking about damage to boilers.

Granted, annual draining a boiler may not introduce enough oxygenated water to have much of an effect on a boiler's lifetime, but I'm sure not doing it unless I have a reason.

EdTheHeaterMan

You may want to look at the condition of the LWCO probe. If there is a significant build up on the probe then you can be sure to include that in your annual startup procedure. If there is very little build up, then perhaps you can forget to check that every other year. But the longest I would wait to check any LWCO probe was 3 years. If the record indicated that a LWCO probe was cleaned in say 1990 then in 1993 I would check it again. Some of them were perfectly clean every inspection, others... not so much. I checked both water and steam system internal boiler conditions regularly at no additional charge for service agreement customers. The extra time it took to unscrew a probe or operate a relief valve or open a boiler drain, was well worth it when you would not get paid for an emergency call if there was a failure in the middle of the season.

Every year for a relief valve and every three years for an internal inspection seemed reasonable to me and my customers. My female customers always questioned me on what an "Internal" inspection was. Since I started wearing those blue gloves on service calls. but that is for another post!

neilc

EdTheHeaterMan said:

My female customers always questioned me on what an "Internal" inspection was. Since I started wearing those blue gloves on service calls. but that is for another post!

you must be a handsome devil you,

SteamingatMohawk

@ethicalpaul As I stated, I got my info from Dan's book. I trust him.

It doesn't matter how much comes in with the feed water, its' the constant in and out of air during heating cycles.

If you don't have a copy of the Lost Art, I strongly suggest you invest in one. It's a great resource created by an ever greater resource.

DanHolohan

Chlorides aren't a problem everywhere. I'm traveling right now, but as I recall, it was centered around New England, Eastern NY, and Lower-NY.

Some more advice from a famous Dead Man:

https://heatinghelp.com/systems-help-center/what-to-do-with-boilers-during-the-summer/

ethicalpaul

SteamingatMohawk said:

@ethicalpaul As I stated, I got my info from Dan's book. I trust him.

It doesn't matter how much comes in with the feed water, its' the constant in and out of air during heating cycles.

If you don't have a copy of the Lost Art, I strongly suggest you invest in one. It's a great resource created by an ever greater resource.

I have a copy. If it says that boilers rot out because of the air cycle and not because of fresh water, I'll eat it.

SteamingatMohawk

Dan meant carbonates not chlorides. 

SteamingatMohawk

Which version, mine is the revised edition 

SteamingatMohawk

@ethical Ranch dressing will soften paper and make it easier to digest. LOL

ethicalpaul

I have a copy. If it says that boilers rot out because of the air cycle and not because of fresh water, I'll eat it.

pedmec

I do think Dan meant chlorides as that is what Burnham has stated is eating there steam boilers up here in Massachusetts

SteamingatMohawk

Did you read the text in the book?

This discussion is about what is written in Dan's book pages 191-192. Don't change the subject.

SteamingatMohawk

Besides, process work is fundamentally different. They are closed loop systems. Those boilers don't vent to the atmosphere like residential steam does.

pedmec

Of course i read the book. but Dan spoke about chlorides in this post, he's not referring to his book. chlorides, according to Burnham, as stated before, is whats is eating the boilers up here in the northeast. they claim they have done extensive testing and that's what they are claiming. Burnham independence boilers are lucky to get a little over ten years. Holes constantly developing above the water line.

Got to be honest thou. Haven't read it in a while lol. Had the original print before it went into spiral bound and lost a lot of pages. Had to buy another one

ethicalpaul

SteamingatMohawk said:

Besides, process work is fundamentally different. They are closed loop systems. Those boilers don't vent to the atmosphere like residential steam does.

Of course process work is different. But the point is that fresh water (due to process work, or due to leaks) is known to be a boiler killer. I am not sure why we are fighting about this.

SteamingatMohawk

My comment in this discussion did not start out talking about chlorides. The "argument" is about what is stated as a specific situation in residential steam heat systems as described in Dan's book and nothing else.

I have to wonder why Burnham appears to have such a problem. My HB Smith boiler is 20+ years old and I have absolutely no indication of such a problem.

To be honest with you, I am somewhat "surprised" the industry doesn't advocate feedwater pretreatment rather than dumping chemicals into the system. There are too many people unfamiliar with water chemistry in the residential setting to have systems hostage to whatever the town/city/well inject into their boilers. It seems to make more sense to prevent unwanted elements/compounds from getting into the boiler in the first place, then treating the boiler water to minimize corrosion.

Even so, the repetitive introduction of fresh air into the systems on cooldown cannot be eliminated without the system design being significantly altered.

I am not a water chemist. I do trust what Dan has to say.

For the benefit of others reading this discussion, I have requested permission from Erin to post the section in Dan's book on this matter, so everyone is on the same page of the original intent of my comment.


We should also recognize the discussion in Lost Art is about corrosion in the system, while Burnham's issue is with corrosion at the waterline in the boiler.

SteamingatMohawk

Remember this part of the discussion started with oxygen introduced by the feedwater being the culprit.


This is the text from the book. The link to the Help Center is listed at the end.


I hope we’re at the point where we can agree that proper venting is going to save fuel and balance systems. Not only does air slow the steam down, it also acts as a great insulator. Did you know that a film of air just 1/25th of an inch wide offers the same resistance to heat as a 4-foot-thick wall of iron?

But there’s another important reason for efficient venting, and that’s condensate grooving. If you’ve worked with steam, you’ve seen the results of this destructive force. You just may not have fully understood what was causing it.

Condensate grooving is the main reason why so many underground returns leak. It’s a persistent, gnawing force that weakens joints and allows water hammer to tear pipes from fittings. It’s the primary cause of unit heater and radiator failure.

And it’s as natural to steam systems as boiling water.

The main cause of condensate grooving is carbon dioxide. It’s a simple process. When carbon dioxide mixes with condensate you get carbonic acid. And carbonic acid is bad news! If you were to take a pH reading on the condensate found in most steam systems, you’d get a reading well below 7.0. That’s on the “acid” side and, obviously, not good for the pipes.

The chemical reaction that takes place inside the system looks like this:

formula

Carbon dioxide is a byproduct of boiling water. Every time a boiler steams, it produces the stuff that will eventually destroy the system. That’s ironic, isn’t it?

The boiler can’t help making this stuff because there are compounds called carbonates and bicarbonates present in feed water that break down when the water boils. That chemical reaction, the breakdown of the carbonates and bicarbonates, produces three things: water, hydroxide (in itself, also very corrosive), and carbon dioxide.

Carbon dioxide, which is, of course, a gas, moves out into the system with the steam. If it’s not quickly vented it will mix with and dissolve in the condensate that’s formed as the steam condenses. The acid that results from this chemical marriage goes right to work on the system components.

And to make matters worse, we also have oxygen in a steam system. It enters through the air vents every time the system pressure drops to zero.

Oxygen speeds up the corrosive attack of the condensate by throwing rust (ferric hydroxide) into the mix. (I’ll spare you the chemical formula for that whole process. If you’d like to see what it looks like, just open the drain valve on any steam system.)

So the importance of proper venting becomes even more apparent when you start thinking about rotting pipes and a bushel basket of sludge.

Want to limit system corrosion? It’s all in the venting!



(This is an excerpt from Dan Holohan's book The Lost Art of Steam Heating Revisited.)



https://heatinghelp.com/systems-help-center/air-vents-and-steam-system-corrosion/

ethicalpaul

Thanks for that.

I guess maybe my possibly last word about this would be: if fresh air is the cause of so much corrosion, then why do steam mains and radiator runouts, which get refreshed with completely fresh air every steam cycle, last for over a hundred years while the boilers rot out in 7-30 years?

My best guess about burnham is either very thin castings or a design that allows the upper areas of the sections to get too hot, accelerating corrosion at the top of the sections where we seem to often see it on the IN series.

SteamingatMohawk

I think this is a tie.

The initial subject was oxygen in the feedwater. What I reported was focused on the piping, while the Burnham issue is the boiler. Perhaps, because the nature of the boiling cycle within the boiler is different from sending low pressure "dry" steam throughout the "system", what goes on may be different.

The boiler retains all the solids (dissolved or not) and expels any gases to some extent. Unless there is some mechanism for carryover of gases and solids, the steam should be pure H2O in gaseous form. By the way, HCl is a gas above -121F.

Think of all the different elements and compounds that are in your home water supply. What about fluoride in the water? If it reacts with hydrogen, you may get hydrofluoric acid. What else could be going on with the other chemicals in feedwater?

I wonder if there is a simple system available that circulates and treats the boiler water filtering out anything that is introduced by feedwater and maintains proper pH, etc.

mygardenshed

I’m not too sure I’ve gotten the answer I was looking for which is rare on here. I’ll skim, drain the wet returns and flush the boiler prior to our next heating season.
A heartfelt happy Memorial Day to all.

SteamingatMohawk

Whatever floats your boat.

ethicalpaul

mygardenshed said:

I’m not too sure I’ve gotten the answer I was looking for which is rare on here. I’ll skim, drain the wet returns and flush the boiler prior to our next heating season.
A heartfelt happy Memorial Day to all.

What answer were you looking for?

here is the answer i gave you right after your post: https://forum.heatinghelp.com/discussion/comment/1700159/#Comment_1700159