So my prochem performer heat HX has started leaking so bad I can't use it. My tm is down. I'm a steam fitter / hvac repairman by trade for 20 years. Is there a way or has anyone ever rewound a new tube around the hx? My other choice is to build my own version of the little giant propane water heater. I can build it for about $500. Has anyone ever done this before . Rewound a new coil or is it better to go the other way and build a heater.