What happened here?

T1263

Steamhead

Boiler was dry-fired, as in, operated without water in it?

bucksnort

Looks like it blew it's nuts.

ch4man

firebox insulation fell, just didn't cover enough of the burners to shut itself down and it burned itself up.
Burnhan series 3 (I forget the model, residential sized) current model, to back 5-7 years have had this issue enough that Burnham has issued a service bulletin and they'll pay parts and a labor allowance

SuperTech

Looking at that picture the first thing that came to mind is that the house caught on fire and someone decided not to change out the boiler after other repairs were made. I doubt that is actually the case, is there any other pictures of the boiler available?

T1263

thank you all for your responses! There was indeed a fire in the house. Thankfully the fireproof door did its job so it was contained and extinguished quickly. We’re trying to understand how it happened as it seemed sudden. The boiler is in tact and clean inside.

T1263

T1263

Is there some sort of insulation on that piece that could have melted?

Zman

I'd be willing to bet the boiler did not have any water in it.

T1263

Anything here give any more clues?:

Steamhead

Only other thing I can think of is someone may have been storing gasoline or some other flammable substance in that basement, it produced flammable vapors, and the boiler came on and lit them off. This is why gas water heaters now have to have Flammable Vapor Ignition Resistant (FVIR) systems built in- in other words, they have to be stupid-proof.

mattmia2

If it was dry fired, wouldn't the lack of heat be noticeable?

There has to be a background story here that is missing. Is stuff around it on the floor burned or just the boiler? Was anyone there when it happened?

HVACNUT

Lack of combustion air, then all of a sudden, a lot of combustion air?

The Steam Whisperer

All those damaged parts are plastic. It could have gotten pretty hot in the boiler room if the house was on fire, so the plastic parts melted. The fireproofing can stop the fire for awhile, but the heat can get pretty intense as it builds up.

T1263

The fire was only in the boiler room.
Only those specific places on the boiler were burned/ singed. There was fire in the room so some things melted and ignited but very little

T1263

Nothing flammable stored there

mattmia2

Is there currently water in the boiler?

was it heating just prior to this?

i suppose there could have been some sort of rollout event or gas leak inside the boiler

Steamhead

I'm assuming the fire department's investigators will be looking into this. Please post the results.

Perhaps the most important question: Was anyone hurt?

Ironman

Judging by the fact that the solder boiled out of the joint above the pump, I’d say either a run away or dry fired boiler.

T1263

Thank you. It was out very quickly.
the smoke was very sudden but the fire department was very quick. 

@ironman- what’s a run away?

EBEBRATT-Ed

@Ironman

I noticed the solder as well 500-550 degrees. It's a wonder there is any house left standing

T1263

How come only that piece is charred and nothing around it? Everything near it is very clean

Ironman

T1263 said:

Thank you. It was out very quickly.
the smoke was very sudden but the fire department was very quick. 

@ironman- what’s a run away?

Run away boiler: one that doesn't shut off. Like a stuck throttle on a car.

mattmia2

So this was heating the house up until some moments before it caught fire right?

Either the pump and the limit fails or more likely the gas valve sticks open.
The non-circulating water in the boiler continues to heat until it boils.
The boiling water opens the relief valve and releases superheated water.
The prv doesn't open and bring in water to cool things down because the pressure is already over its setpoint.
After some boiling water is released the relief valve closes momentarily, boiler continues to heat the remaining water until the pressure increases and blows off the relief valve again.
This repeats until all the water boils out of the boiler.
Now all the heat from the burner starts cooking the dry boiler and casing and the things in and near the boiler start getting hot enough to burn.

T1263

thank you all. 

Glad all ok.
just was trying to understand what happened because there didn’t seem to be any smell of anything burning a little while before.
is this fixable? 

Steamhead

T1263 said:

thank you all. 

Glad all ok.
just was trying to understand what happened because there didn’t seem to be any smell of anything burning a little while before.
is this fixable? 

NO!!!!!

You need to replace that boiler- it's, literally, toast.

Eric_32

Did the boiler room have enough combustion air? What size room was this? Was there a door or grills cut into the wall for combustion air? You can see metal studs close to the boiler. A plugged up boiler with flame roll out due to insufficient combustion air?

HVACNUT

Was the Fire Marshal on vacation? That is their job.
Combustion air looks like it might be an issue. That was an enclosed little room right?

EdTheHeaterMan

Fire insurance (homeowners insurance) should cover the damage to the boiler, as long as you have properly maintained the boiler and did not violate any building code requirements when the boiler room was enclosed. Your insurance adjuster will know what is covered. Remember... the one the insurance company sends works for them. You may want to hire a public adjuster that represents your interest if you are not satisfied with the insurance company's decision.

Yours Truly,
Mr.Ed

T1263

thank you
yes it was a small room with a fire door.
no grill. But there’s air in there I believe
AC ducts go out 
could be I’m not describing well enough

EdTheHeaterMan

You have what is called a confined space. if your basement was not finished and the full length of the house with an 8 ft ceiling, and the basement door had a louver in the top and the bottom panels, then you may have an unconfined space. This means there is sufficient air for combustion. a confined space means there is not sufficient air for combustion. An air condition duct does not count when calculating combustion air. (mostly because the air conditioner is not operating when the heater is operating.)

Think about it, the air for the flame has an exhaust pipe going up a chimney or metal vent thru the roof. Where is all that air coming from?

Here is a little article that will help you understand combustion air and confined spaces.
https://www.pct.edu/files/imported/business/nssc/docs/articles/CAZ_Zone_and_Code.pdf

mattmia2

As @Ironman pointed out, the solder melted out of that adapter at the circulator and that coupld only happen if there was no water in the pipe, so it wasn't a rollout issue, most likely the controls failed and boiled all of the water out of the boiler although it is also possible it leaked out somewhere and whatever the lwco device is failed.

JUGHNE

There is a hi limit manual reset on the supply outlet, but it is on a 12" or so branch off of a tee.
One wonders if it were closer to the riser IF it may have opened, even without water.

Unit maybe too old to have flame rollout fuse or plugged flue limit.

But, even if all of these limits opened the gas valve may have been stuck open....
turned it into a steamer.....
One wonders if the water supply valve was open.
Probably no LWCO.

It would be very interesting to see the forensic report on all this.

Henry

How about proper pump installation! For over 20 years, I have implemented a standard: 5 dimensions of straight pipe before and after a pump. ASHRAE say 5 to 10. Plumbers can remember 5 and 5. Otherwise, you can have cavitation.

dcbraley

Fire looks like something combustible stored next to the boiler. The rust spot below the circulator looks like the area of most heat damage, theres really nothing inside the boiler to burn. Possibly the boiler fires, the material ignites from conducted or radiated heat or a liquid can has developed a leak and vapors ignite. The fire grows and melts the automatic vent damper, possibly killing the call for heat as the fire runs out of fuel to burn.