How to use "furnace" in a sentence

There's a gas furnace."

"Where's the furnace? In the garage?"

He went to the furnace, put his heavy tool kit on the floor, and hunkered down

He opened a hinged plate, exposing the furnace's workings

"He wanted to check my furnace, make sure there wasn't any gas escaping."

He checked the furnace, and it was okay."

"It took him that long to check out the furnace?"

"Where's your furnace?"

"The furnace!"

"I'll bet the bastard who rigged my furnace is in that truck."