How hot does the floor of the heat bell get. My riser sits on a fire brick. The firebrick sits on the floor of the heat bell. In my haste I burried a 3/8 inch 20 ft copper coil 2 inches below the floor packed with cob and small rocks, so I could heat water. I was going to have an elevated water barrel ( 18 inch rise) and hook up two pipes from the barrel to feed the coil. I have good ideas, but sometimes lack the thinking it thru part. Is the temperature in the floor too high? Will I blow my face off? Help me Obiwan, your my only hope. I hope my description is good enough, I can explain further.