URGENT - Hyrdrogn in NEW Central Heat Systm.

[sterose]

Sterose - a steady continuous build of gas is the problem - ie approx 0.1 bar every 2 days - this seems to remain the same.

Example: Last week I de-gassed the radiators (extracting tiny amounts of fizzy water as usual) press went down to 1.1 bar - Today the press reads 2.4 bar! So if I do the same today, the press will likey go back down to 1.1, and with gas/time it will rise again.

After the system was drained last time, there's no 'noticable/significant' change in the 'slow rise' of gas in the system.

The gas is heard through pipes occasionally, as well as accumulating in radiators (2-3 out of 8 radiators) - so I think whatever the cause, it must be either in the water as a whole, the pipes or the boiler, ie not just confined to radiators (my conclusion only). It's puzzled the heck out of me!
and it's a worry . . .

Gas from radiator burnt like a pressuried lighter flame first time (only time) we investigated the gas - ie opposite of a slow candle flame - it's a pressurised system anyway at about 2.3 bar.

Cheers

If you're sure it's Hydrogen, it must be some sort of chemical reaction. Unfortunately, i'm not a chemist, and I cant help you with exactly where or why the gas is being produced.

I'd just leave the system alone (i.e. turned off), until you get, like oilman suggests, some concrete facts about the problem.

 

[masona]

The whole system recently installed totally new.

Out of frustration, I am about to ask the installers to take the whole system down!

Can you not get the installer back?

 

[boilerbeasty]

Hydrogen should pop - its a mini explosion. If its slow burning or a yellow flame, its not pure hydrogen or just hydrogen.
Something funny is going on here, and you ought to ask the installer back to sort it out. I'd be suprised if this is what he planned or thought he'd put into your house and wouldn't like to leave it in a mess.

 

[ChrisR]

Seems to be uncertainty about the obvious - Hydrogen is a product of RUSTING!
Rust is Iron oxide, which can occur in lots of different compounds like FeO, Fe2O3, Fe3O4 where Fe is iron and O is Oxygen.
The radiators supply the Iron.
The Oxygen comes from Water, which is H2O.
So, broadly,
Fe + H2O goes to FEO +H2
H is Hydrogen.
Electrolysis can help or hinder the reaction, but isn't necessary. Flux is a big help!

 

[sterose]

Seems to be uncertainty about the obvious - Hydrogen is a product of RUSTING!
Rust is Iron oxide, which can occur in lots of different compounds like FeO, Fe2O3, Fe3O4 where Fe is iron and O is Oxygen.
The radiators supply the Iron.
The Oxygen comes from Water, which is H2O.
So, broadly,
Fe + H2O goes to FEO +H2
H is Hydrogen.
Electrolysis can help or hinder the reaction, but isn't necessary. Flux is a big help!

You obvioiusly ( ) went to the wrong chemistry class.

You will infact find that water alone does not rust iron.
It is the air dissolved in the water that causes the rust. Boiling removes the air from the water.

This is why electrolysis has been suggested as the cause, because water does not easily part into oxygen and hydrogen.

Incidentally, this is the reason you should not regurlarly fill the system with fresh aerated water, because it causes rampant corrosion.

 

[universe]

As you know, solution sample sent, awaiting results.

General/uniform corrosion is affacted by dissolved oxygen, hydrogen ions (H+) & water (OH -ve), leading to hydrogen gas & mainly ferrous hydroxide (rust) -> in aqueous conditions.
Bi-metallic contact corrosion in aqueous environments ACCELERATES the rust/corrosion reactions in localised/pitting form.
Iron corrosion in dry air will be mainly iron oxide products.
Acidity enhances iron corrosion (more H+), however, alkalinity can 'passivate/reduce' iron corrosion.
Sentinel's literature -> Chloride is an indication of flux.

In my case -> This much hydrogen eg 2.5 cold radiators due to gas every week (approx) just looks too much gas for 'nromal' general/uniform water corrosion - unless there's a fesh supply of water/dissolved oxygen into system or low pH or whatever is accelerating the reactions. The water still is clear/clean looking.

Boiler's heat exchanger I beleive is stainless which should be OK if contaminated/contacted with Copper pieces.

System was flushed initially with X300, warm circulation for 1hr.

I will update you asap, but please continue writing your thoughts. Cheers.

 

[sterose]

As you know, solution sample sent, awaiting results.

General/uniform corrosion is affacted by dissolved oxygen, hydrogen ions (H+) & water (OH -ve), leading to hydrogen gas & mainly ferrous hydroxide (rust) -> in aqueous conditions.
Bi-metallic contact corrosion in aqueous environments ACCELERATES the rust/corrosion reactions in localised/pitting form.
Iron corrosion in dry air will be mainly iron oxide products.
Acidity enhances iron corrosion (more H+), however, alkalinity can 'passivate/reduce' iron corrosion.
Sentinel's literature -> Chloride is an indication of flux.

Again, I think the problem is your (lack of) attendance at a chemistry class.

"General/uniform corrosion is affacted by dissolved oxygen"
Yes.

"hydrogen ions (H+) & water (OH -ve)"
No.
You will find that OH- is hydroxide. Not water.

"leading to hydrogen gas & mainly ferrous hydroxide (rust)"
No. Again, this only happens with acids.

"Acidity enhances iron corrosion "
Yes.
However, acid is not water.

So the problem is acid. And unless HCl (thats Hydrochloric acid), was added to the water. Severe enough acidity is an unliekly problem.

 

[universe]

sterose - I'm not sure who you're referring to, but good to see your messages.
Water is H2O or H-OH -> giving (H+ plus OH-) which is the basis for corrosion.
Hydrogen ions (H+) drive corrosion in water (acidic conditions).
Hydroxide ions (OH-) drive corrosion in water (alkaline conditions).
ie, acidity/alkalinity determine the corrosion direction, as explained above - eg acidic solutions, more hydrogen ions, more corrosion.
Hydrogen gas (H2) is generated by corrosion in water - because watever aggressive chemical element is driving the corrosion, its excess electrons are taken up by hydrogen ions (H+) to form hydrogen gas (H2).
Oxygen is an agressive element, so more dissolved oxygen, more corrosion - it drives the (OH-) chain reaction.
Dissolved carbon dioxide (CO2) enhances corrosion - drives the H+ reaction, it combines with H+ from water, changes to carbonic acid (pepsi/coke) - very mild acidic pH of 5.5 but can go through steel like butter - severe pitting/pin-hole corrosion under temperature and with flow - eg oil/gas well & transport pipelines are very susceptible to this.
Iron hydroxide is the corrosion product (rust) in water/aqueous solutions - its build up may eventually reduce corrosion as in old sunken ships.
Hydrochloric acid is HCl - it drives the H+ reaction side, but it also adds a lot of H+ of its own therefore also reduces the pH - anything below 5.
Chloride (Cl-) also enhances corrosion (eg from salts or acids), particularly damaging to Stainless or Aluminium, gives pitting/pin-hole corrosion.
Flux may produce acidic conditions - I don't know flux composition, but I guess because of Cl which combines with H+ of water to result in hydrochloric acid (HCl), giving fast localised corrosion - Sentinel litrature says chloride relates to flux.
I do not know if the water in this system is neutral, acidic or alkaline.
Anyway the test will tell us more . . . I hope.

 

[sterose]

sterose - I'm not sure who you're referring to, but good to see your messages.
Water is H2O or H-OH -> giving (H+ plus OH-) which is the basis for corrosion.
Hydrogen ions (H+) drive corrosion in water (acidic conditions).
Hydroxide ions (OH-) drive corrosion in water (alkaline conditions).
ie, acidity/alkalinity determine the corrosion direction, as explained above - eg acidic solutions, more hydrogen ions, more corrosion.
Hydrogen gas (H2) is generated by corrosion in water - because watever aggressive chemical element is driving the corrosion, its excess electrons are taken up by hydrogen ions (H+) to form hydrogen gas (H2).
Oxygen is an agressive element, so more dissolved oxygen, more corrosion - it drives the (OH-) chain reaction.
Dissolved carbon dioxide (CO2) enhances corrosion - drives the H+ reaction, it combines with H+ from water, changes to carbonic acid (pepsi/coke) - very mild acidic pH of 5.5 but can go through steel like butter - severe pitting/pin-hole corrosion under temperature and with flow - eg oil/gas well & transport pipelines are very susceptible to this.
Iron hydroxide is the corrosion product (rust) in water/aqueous solutions - its build up may eventually reduce corrosion as in old sunken ships.
Hydrochloric acid is HCl - it drives the H+ reaction side, but it also adds a lot of H+ of its own therefore also reduces the pH - anything below 5.
Chloride (Cl-) also enhances corrosion (eg from salts or acids), particularly damaging to Stainless or Aluminium, gives pitting/pin-hole corrosion.
Flux may produce acidic conditions - I don't know flux composition, but I guess because of Cl which combines with H+ of water to result in hydrochloric acid (HCl), giving fast localised corrosion - Sentinel litrature says chloride relates to flux.
I do not know if the water in this system is neutral, acidic or alkaline.
Anyway the test will tell us more . . . I hope.

"I'm not sure who you're referring to"
You wrote a message; the one before mine.

Although the 'gist' of your message seems to show understanding, you do in fact wildly misunderstand the science.

"Water is H2O or H-OH -> giving (H+ plus OH-) which is the basis for corrosion."
This does not occur in water on its own. H+ is present in acids. OH- is present in alkalis. Whe combined they produce water (neutralisation) again; they do not seperate from it. By definition, for the 'water' (i.e. water and another substance) to be corrosive, it must have an element that creates the H+ or OH-. Think of it like a magnet. In the prescence of the magnet, the H+ and OH- ions seperate, when the magnet is removed, the ions join again. Chlorine is a good 'magnet', it is very electronegative. Without the magnet, it is, literally, water; not corrosive.

"Hydrogen ions (H+) drive corrosion in water (acidic conditions).
Hydroxide ions (OH-) drive corrosion in water (alkaline conditions)."
Correct.

"Hydrogen gas (H2) is generated by corrosion in water"
Yes, in the presence of a substance that creates acidic (or alkaline) conditions, not by the water itself.

"because watever aggressive chemical element is driving the corrosion, its excess electrons are taken up by hydrogen ions (H+) to form hydrogen gas (H2)."
No. Hydrogen exists where is can as a diatomic molecule: H2. The process from H to H2 involves no change in number of electrons. And there is no such thing as 'excess' electrons.

H+ is basically a proton. H is a proton and electron. If H+ exists, where did its electron go in the first place. H+ was 'stolen' by another molecule (i.e. Hydrogen Chloride dissolved into water: the chlorine atom attracts the H atom (creating H+), but leaves the electron behind with the water which forms OH-).

"Dissolved carbon dioxide (CO2) enhances corrosion - drives the H+ reaction, it combines with H+ from water, changes to carbonic acid (pepsi/coke) - very mild acidic pH of 5.5 but can go through steel like butter"
When CO2 dissolves in water, the H (i.e. not H+) part of the water is attracted to the CO2, and this produces H+ ions and OH- ions. It does not 'combine with H+'.

"Iron hydroxide is the corrosion product (rust) in water/aqueous solutions"
Again, I dont think it is correct. Rust is iron oxide.

"Hydrochloric acid is HCl - it drives the H+ reaction side, but it also adds a lot of H+ of its own therefore also reduces the pH - anything below 5.
Chloride (Cl-) also enhances corrosion (eg from salts or acids)"

It does not 'add' H+. IT ACTUALLY MAKES IT FROM THE WATER. It is the negative attraction of chlorine that attracts the H away from the water. It leaves its electron behind and therefore creates H+, and OH- respectively.

I would be very keen to carry on this debate if you wish. Seriously.

 

[sterose]

I think I'll write the above post again. I have ranted on a bit , and it has lost all meaning.

1. Water alone does not corrode.

2. Acid Basics.

When certain substances are added or dissolved into water, it causes acids to be formed. (i.e. Hydrogen Chloride dissolved in water = Hydrochloric Acid. This is because the chlorine atom is strongly electronegative, and it attracts the H away from the water. The H leaves its electron behind on the water molecule though, and this causes an imbalance in charge, and so H+ is formed, and OH- is formed.

3. Oxygen is, on the other hand, not an acid but simply a more reactive element. When in contact with iron, it forms FeO.

What I'm getting at here, something we both agree on, is that there is obviously 'something in the water', and it's causing the corrosion.

Hydrogen is not produced by water on its own. And if it's Hydrogen, either there is some sort of electrolysis happening (most, most unlikely), or there is a massive amount of corrosion happening somewhere, with the water having some sort of acid in it.

My money says its not hydrogen, but some other flammable gas.

 

[universe]

Thanks for your 2 posts sterose.

Iron corrosion in water follows 2 potential chain reactions:
H+ route - in acid or 'neutral' water.
OH- route - in alkaline water or when dissolved oxygen present.

In neutral/acid water, the rate of corrosion is dependent on H+ concentration, the higher the [H+], the lower the pH, the stronger the acid/water solution, the higher the rate of corrosion.
In alkaline/water solutions, the rate is higher with higher [OH-] concentration, ie stronger base/water.

Oxygen & Hydrogen gases dissolved in water -> Some gases like Oxygen are aggressive towards iron, so when they contact iron, they act 'almost' like copper, eg they act 'almost' like a higher potential metal (bi-metallic corrosion).
However, because iron (Fe) is immersed in water, its active surface barrier is surrounded by a layer of polarised H+ & OH- ions (ie water ions). So these aggressive gases (O. & H.) , first dissolve in water and then attack/affect iron's surface, ie through generated ions like H+ & OH-, these actions also polarises iron by pulling its potential higher up the electrochemical table. In the case of iron, 'initially', the higher the polarisation with respect to its steady-state condition, the higher the corrosion rate - however in the case of iron/steel, if the potential rise is sufficiently high enough (eg by substantially increasing O concentration), the iron/steel will in fact passivate due to its corrosion product build up.
Iron corrosion in dry air/oxygen gas is defined as oxidation - it's dominated by various iron oxides. Iron corrosion in water is dominated by iron hydroxide FeOH compunds, its crystallised structure will reduce aqueous corrosion with time IF NOT distrubed, so burried cast iron pipes, if not disturbed will last many years, same with iron/steel sunken ships . . .
All I wanted to do was to get my life somewhere near 'normal' by fixing my new central heating . . . but now I'm talking polarisation potential . . .

 

[flashbang]

Keep going guy's....... This is fascinating stuff.
Flashbang

 

[masona]

So is it safe to drink water now ?

 

[ChrisR]

You guys seem to have forgotten what pH is - log(base 10) of the concentration of H+ ions . Water is 7! In one mole I guess - can't remember now!
Water contains an equilibrium concentration of H+ and OH- ions. React some of the OH- with the Fe and the equilibrium shifts.
Water rusts iron.

I don't remember as much of this stuff as I might, but I did do A level chemistry and an hons degree in metallurgy..

 

[sterose]

You guys seem to have forgotten what pH is - log(base 10) of the concentration of H+ ions . Water is 7! In one mole I guess - can't remember now!
Water contains an equilibrium concentration of H+ and OH- ions. React some of the OH- with the Fe and the equilibrium shifts.
Water rusts iron.

I don't remember as much of this stuff as I might, but I did do A level chemistry and an hons degree in metallurgy..

Assuming you passed A level, I should take your word for it, that water corrodes.

But I'm fairly sure it doesn't without some other chemical; i.e. the chemical that actually makes it acidic.

"Water contains an equilibrium concentration of H+ and OH- ions."
Until another chemical is added, it is not H+ and OH-, it is water: H20.

For example
Fe + H20 does NOT react.

Fe + HCl > FeCl + H

FeO + HCl > FeCl + H20.

(these are not balanced equations).

You can see that these equations, although the HCl is in water, do not involve any reaction of the actual water.

And once again I would like to state that water is a stable compound and it does not react with anything.