Magnetite causing a hot water boiler to crack

Nimrod66

Hello Forum,
Has anybody out there had any direct experience with a hot water boiler cracking from large quantities of magnetite? If so, do you have any reports that speak to the failure? Maybe going in a different direction, who out there knows an engineer who can take a forensic look at a cracked boiler that is full of magnetite? Thanks for your help.

kcopp

What type of boiler? Cast iron? Stainless steel?
Got pix?
Water quality has certainly killed a boiler or two before....

Jamie Hall

Allow me to make a couple of observations here. The first being that I have been an expert witness in the past, I am not in the slightest interested in being one again.

OK. That's off my chest. Now. Sludge -- including magnetite -- can indeed kill a boiler by impeding circulation, causing localized hot spots and thus cracking. That's pretty well known. However, first, there are no special properties of magnetite which specifically do that. It's a component of sludge (I might note in passing that this is not true of certain pumps; there the magnetic qualities may play into the problems). So. We are talking about a sludge problem.

A sludge problem can only come from improper materials (non-barrier PEX, for instance) or from improper maintenance (not attending to the pH, not adding and maintaining proper corrosion protection, etc. etc, not maintaining filters... the list is long).

The point of this is that if you are attempting to demonstrate that magnetite, per se, was the direct cause of the boiler failure, you are going to have to be able to demonstrate that materials and maintenance did not contribute to the buildup of sludge.

And that is going to be an uphill battle.

Nimrod66

I will attach a photo of the inside of the boiler, which shows the mud at the base of the boiler and also caking the HX tubes. There are places where the normal spacing between HX tubes is completely blocked by caked mud. Mud was 10" deep in the base of the boiler. We believe the boiler failed due to hot spots caused by the mud.

Boiler water was tested with chlorides at 395 PPM, which is 13 x the allowable concentration according to the manufacturer.

We are facing an insurance company for the owner, which commissioned an expert forensics engineer, who seems to think that the mud did not cause the boiler to crack. The author of the report suspects a bad weld. We think his report is biased and incorrect. We are shocked at the inability or reluctance of the owner and insurance company to accept the cause of failure as being a hot spot, which seems obvious. The chlorides are another matter.

We are the manufacturer's representative for the boiler, which is a steel Froling P4 100 pellet boiler.

Gordy

From an insurance companies stand point, in the end it’s going to be what failed, not what caused it to fail.

Now as a rep for the manufacturer, obviously it’s about what caused the failure.

How old is the boiler?
Who did the install?
Was the installation performed with in spec?
Were components used in the system that allowed O2 continually into the system which caused the formation of magnetite ?
Was system water quality in spec, and maintained?

Like @Jamie Hall said uphill all the way. The entity with the most money prevails in the system.........sadly.

Jamie Hall

It is remotely possible that the failure occurred in a weld, not adjacent to it. However, this doesn't prove that the weld was bad -- and would take really expert analysis of the failure (we're talking sections and scanning electron microscopes and microprobes -- the whole banana) to show the origin of the failure.

Worse, showing where the failure occurred will not show why the failure occurred, which is the point -- and as I said before, you are going to have to prove that it was not anything to do with maintenance or materials elsewhere in the system that caused the sludge buildup which may be the cause of the uneven thermal stress which may be the driver of the crack.

Note the "may be"s.

Oh -- and get off the magnetite kick. Whether the sludge is composed of magnetite or some other iron oxide is quite irrelevant.

Canucker

@Jamie Hall is right. You're looking at the direct cause of the crack(possibly the magnetite). The root cause will be found when you find out why the magnetite is there and follow where it points to.

Nimrod66

Getting back to my question: Has anybody out there had any direct experience with a hot water boiler cracking from large quantities of magnetite? If so, do you have any reports that speak to the failure? Maybe going in a different direction, who out there knows an engineer who can take a forensic look at a cracked boiler that is full of magnetite? Thanks for your help.
Regardless of whether the muck is magnetite or ferrous muck by a different name, it doesn't matter. It doesn't matter to me how the muck was formed. I am curious to find reports written about hot water boilers cracking due to muck.

Jamie Hall

You will find lots of reports -- anecdotal and written -- about boilers cracking with muck in them. Due to muck in them? In the same sense as "the engine failed due to lack of oil", yes.

As I tried to point out to you earlier, however, the root cause of the failure isn't the muck, but the lack of maintenance which caused the muck to build up.

There are a number of highly reputable engineering firms which do forensic failure analysis; the easiest way to find them is to Google (or Bing or whatever) "forensic failure analysis". We don't mention price here on the Wall, but based on past experience I would imagine that you will be able to buy several new boilers, installed, for a look at your problem. I might add that to my knowledge none of them work for a contingency fee, nor would any reputable Registered or Professional engineer.

Nimrod66

Thank you for your help. In this case finding the root cause or source of the muck is the responsibility of others.

Zman

The water you describe is unsuitable for a closed hydronic system.
There certainly are not enough solids in a single fill to cause that much "muck".
The system had a leak for a significant period of time to create that kind of mess.
It seems very obvious that the cracks were caused by the thermal stress created by the hot/cold spots.
To prove it to some random engineer hired by an insurance company is a larger challenge. Just like contractors, engineers are not qualified just because they are granted a licence. Insurance companies are good at finding ones that come to the conclusions that suit their needs.