Replace Waterfurnace HWG desuperheater coax coil. Part is covered under Waterfurnace Parts warranty. Labor and refrigerant is not. Remove and replace failed desuperheater water coil. Pressure test with nitrogen at 400psi for 10 minutes. Vacuum down to 500 microns and let sit for 30 minutes for decay test. Charge in 93oz of new R-410A. Installed new ABC board aswell and preformed test run. Refrigerant pressures are within spec. No other issues found or suspected.