Oil furnace explosion - audit, thoughts

I take it you did not have the home and outbuildings looked at by a housing inspection service???

You need to have your insurer send an arson investigator and draw sample of the fuel in the tank to have it sent out for analysis and go from there.

The problem for you starts when the insurers arson investigator walks on the property and asks where the lock for the fuel tank is? Then he or she walks in the garage and sees the furnace "IN THE GARAGE", Then it becomes "LUCY, YOU GOT SOME SPLAINING TO DO".

You have to decide if you want to deal with this as is and possibly have your insurance canceled or simply have the oil dealer remove everything and install a through the wall pro-pain forced air furnace.

my thoughts as a homeowner with a worthless insurer.

Housing inspector………………..NO A qualified HVAC Contractor will know what's required. Home inspectors are a complete waste of money but required!

I do not disagree with Father Jamie or pecmsg,

If the realtor knew anything about building codes the home and outbuildings would have been inspected and the code was followed perhaps this could have been eliminated at the start before the sale.

The national plumbing code, the local plumbing code and the building inspector always ride herd on things like this.

In all my years I have never seen a delayed ignition or puff back or a flooded chamber do that kind of damage. I've see plenty of major delays where some one has jumped the safety or the safety failed. I've seen flue pipes turn into flame throwers and draft regulators embed in drywall but to blow the chamber plates off? WOW. Also I never thought I'd ever use the term "in all my years"

One more thing. That control has a limit to the number of resets it will allow if I'm not mistaken. Someone would have to purposely reset from it's hard lock out a bunch of times. Could it possibly be way way way over fired?

gasoline ad oil will happily mix together permanently but if it is gasoline but it isn't in the tank. if it is gasoline it is vapors from the garage.

it is most likely service related.

the stuff that would cause or prevent something like this isn't written in the code, it is passed on from old techs to new techs, it is barely even written in trade books.

what if it was burning very rich and they let enough air in for the co and soot to suddenly burn all at once?

is there a combustion analysis report from their previous visit?

so they didn't do a combustion analysis after they changed a bunch of things or in the process of seeing if the reason it locked out was because it wasn't burning properly and was intermittently going out?

how would the motor and the transformer both be bad?

IMHO, this blast was too big for an untampered with delayed ignition. That oil spray must have been on for a good while for a blast like that. Perhaps the tech thought the burner had lost prime and put the primary into "pump prime" mode, which would keep the burner running and spraying for 2 minutes, not realizing that there was no ignition. When it finally got a spark, the whole furnace was full of oil vapor. That's my guess. Cracked electrode? Carbon bridge?

Playing devil's advocate here - the motor could have been the culprit for the no-start but the ignition transformer may have also had a weakish spark?

I mean it did peel the cover off of the front of the combustion chamber.

I notice there is no spring loaded observation door to release the pressure.

Kero is more volatile than heating oil but I don't know if it's so much more so that it will cause an explosion like you had. In the back of my mind, I still think the tech mishandled the burner, maybe running it on "prime" without opening the bleeder first.

The tech wasn't paying attention to something that's for sure. For 46 years I worked on oil #2,4 and 6 and gas burner up to about 100gph (15 million btu/hour) and a few larger than that.

Yeah, I have had my eyebrows singed a few times and some soot in my face a couple of times and that was while paying attention.

There is no possibility that that tech was paying attention to what was happening.

You don't make assumptions when working on burners no matter how many years you have worked on them or how much you think you know.

There are lots of people that have commented on this thread that have forgotten more than I will ever know.

I have seen a few residential oil fired boilers and oil fired warm air furnaces with similar results. In most cases the soot from the unit would coat most of the basement, sometimes the entire house. I have seen smoke pipe look like there was dynamite placed inside. I have seen boilers with spring loaded doors at the breach that blew open. Growing up (before my father went into the heating business) I can recall the chimney clean-out in our slab house blowing out into the kitchen, blowing soot everywhere. In this case It looks like the furnace must have been pretty clean, as there is almost no soot laying around.

I only witnessed one of the explosions while on site (our house) the rest were after the fact. In most if not every case the cause of the explosion was due to delayed ignition. The combustion chamber, possibly the rest of the unit and perhaps the smoke pipe all filled with oil vapors and finally the ignition took place and BOOM!

I looked at one job at a Fire Station where they wanted to replace the boiler.

It was an old boiler with two fire doors that swung open.

When I looked at it they had a chain looped through the door handles chaining the doors shut.

I said " I see you getting some delayed ignition"