Denied coverage for water boiler that broke down during fire

Hey all, I feel kinda stuck in a pickle and I’m open to any and all advice. I had a kitchen fire in my home last month, not catastrophic but going to require a kitchen demo and full home cleaning because of significant smoke damage. I have no major issues with the insurance company on this front.

My issue is with my natural gas water boiler. I spoke with the fire dept chief the day of. He informed me during the response to the fire they killed the gas feed into the system and I should have someone come out and start it back up. When my local HVAC company came out they informed me my system broke down when the gas feed was shut off. It needs to be replaced.

Enter insurance company. I sent in a statement from the HVAC company, the fire dept report, and the quote for the replacement. The insurance company sent out an “investigator”, he spent 2 minutes at my house and sent the insurance company a copy-and-paste report stating the cause of failure as wear and tear. Subsequently they denied coverage of the boiler.
I’ve had some tense conversations with my adjuster since (I remained calm and diplomatic but stern) but he’s stood firm and now he’s giving the runaround, saying I can speak with his manager.

For transparency the boiler was 14 years old and nearing the end of its service life, but I am adamant that it breaking down during the response to the fire makes it part of the coverage scope. Am I out of luck here? I suspect my total payment isn’t going to be high enough to justify a public adjuster and I’m unsure of whether I have enough of a case to justify an attorney or lodging a complaint with my state insurance bureau. Any advice would be greatly appreciated!