Depends on why it blew up, did someone blow it up ? Was there a non related gas leak that blew up part of the house,

Or did it just stop working.

Insurance does not pay for the normal wear and tear and things breaking down

Agree - 'breaking down' is rarely insured, a tree or car or flood or vandal has to ruin it, and even then your policy may have disclaimers about requiring a separate flood policy. Even frozen pipes aren't covered much anymore! You have to read your particular policy very carefully.

It appears, since now my water heater has cracked, that the heating company is on site. The unit is approximately 12 years old. They (heating company) 1st said that a gasket blew out in the Boiler (I have hot water going to 2 air handlers plus a hot water heater) which caused the water to go into the combustion chamber, which detonated the unit when it started up (oil fired).
The issue I had when I got home was that in the attic (3 stories up) the insulation on the pipes was melted! Today they commented that the only way this Boiler (Peerless design) would have destroyed itself this way if the temperature of the hot water went to steam. Not sure if the temp went up from lack of water or if the high temp limit didn't trip the unit.

Thanks. I did contact the insurance Co. The 1st thing they stated was the "appliance" is not covered but any damages resulting from its failure is covered (water, smoke)

We had a Pearless steam boiler (1991) when we bought the house in 2006. Last October the boiler was cracked and we had to replace the boiler. We applied to see if insurance could cover a the replacement seeing that the boiler was a hazard. They came and check and said... due to corrosion of the boiler it was not possible. That doesn't sound right to me. So, if the house blew up due to us turning on the boiler, they wouldn't pay?

Any suggestions??

If the house blew up you would have coverage for damage to the house and furnishings that were ruined, assuming that you could provide proof of regular good maintenance on the boiler. But the boiler would probably be depreciated down to nothing, being 21 years old. A crack in the boiler is a hazard covered under the warranty of the company that made the boiler (not likely by then), so it comes under normal wear and tear of the house and appliances that you are responsible for.
Now you see how little insurance covers. Fire is really the biggie, and even then, if they can prove that you did something like your own wiring without a permit and license, or had a woodstove not meeting code, they will deny your claim. Storm damage is second, I think.
In short, they will deny you any chance they can.
These days, many people find that they have to sue to get a claim honored.
But I happen to agree with them about your boiler not being something they would pay to replace. By your logic, a homeowner could just let everything get old enough to break down and have insurance pay for a new one.