Try a w sawzall / or fine of good teeth twice met (demolition blades) or carbide grit lepides.Http: / / http://www.C4carbides.Com/files/C4% 20Recip% 20Flyer. PdfMporei help take Drilling / sledge hammer to the side heater busting up any investment there before starting to cut.

i must agree with the above answers, you can either use a sawzall or a lens to reduce your heater parts to carry out

Make sure it’s gas or oil lines properly removed and sealed before the start.

And draining the water out too, these are usually dissolved in a professional acetylene welding / cutting torch and / or sledge hammer.

Some people here suggested Sawzall but when your unit needs parts iron cut the sawzall wont quit. Sawzall is good for the bolts and thin Tyr metallo.Mporeite be asking for a company like 1-800-GOT-JUNK because the metal has some value as scrap.

Similar project, I made handles using 3/4″ pipe and threaded them into 3/4″ tank openings.