I own a Raypak 2100 Digital heater approx 10 yrs old. It has worked well, but during my pool opening the tech said the drain plug popped out and might be stripped. If the drain plug is not the problem, then the plastic head unit might be stripped and would need replacement. When the pool company's owner called to discuss ordering the drain plug, he said if that did not work I should replace the entire heater ($3500) because the cost of replacing the head unit is so high due to the amount of labor required. He said most heaters last about seven years and I should not pay a lot to repair mine. Is this true? I hope the new drain plug will work, but if not I would hate to replace the entire heater due to stripped threads on the head unit.