Help with furnace and construction project

Good evening,
Would prefer to hire a member in these fields.

Project 1:
Fired up a new gas furnace in the new to me shop and it doesn't seem to working properly. Need it inspected or replaced.

Project 2:
I have an upstairs mezzanine and the "engineer" missed a 2x10 scab joint over a span. Framing and drywall completed, hauled parts up stairs and noticed a few days later a massive sag in the ceiling.

Located in Broomfield. Pm here or call/text 970-412-73two3.

Best,
Tin