Rinnai K26i Thermal Fuse Harness Assembly The Rinnai K26i Thermal Fuse Harness Assembly - a proper replacement wiring assembly for the Rinnai K26i continuous flow water heater. This is a critical piece of kit that links the thermal fuse, a vital safety device that stops the water heater from overheating, to the control system so the thing shuts down safely if it gets too hot. As a genuine Rinnai part made to their exact specs, this harness supports rock solid safety monitoring and proper chat between the thermal fuse and the control electronics in the heater. When that thermal fuse decides to call it a day or the wiring gets all mucked up, swapping out the harness with a genuine Rinnai part will put the water heater back in safe hands and keep you in line with safety regulations. ⚠️ Important Bit: Don't e