Due to the thickness and the petroleum composition of shrink wrap I strongly do not believe that will suffice. I have used heavy cardboard and refrigeration foam pipe insulation ( rubbertex ). Do not use the cheap / hard plumbing pipe insulation. I am sure it will react like the wiring insulation does. Also insulate all sections where the wiring would touch the liner insulation, IE; behind the m.pcb, on the way to the dispenser, etc.