Rinnai K26i Thermal Fuse Harness Assembly (P26IKM-725) The thermal fuse on a Rinnai K26i continuous flow water heater is a critical overheat safety device, and this harness is what connects it to the control system so the appliance can shut down safely if it overheats. Without a sound connection between the two, that safety monitoring can't function as intended. This is the genuine Rinnai harness, made to the same specification as the original fitted at the factory, restoring proper communication between the thermal fuse and the control electronics. Where the original harness has failed, corroded, or been damaged, replacing it with the genuine part puts the safety circuit back to full working order and keeps the appliance compliant with the safety monitoring it was designed around. ⚠ Important: This is a safety-critical com