Rinnai 1500E/1200E Fuse Harness (P1500EKM-721) On Rinnai HDC1500E and HDC1200E commercial water heaters, the fuse harness is what connects the thermal fuse — a critical overheat safety device — to the control system, allowing the appliance to shut down safely if it runs too hot. As with any wiring component in a safety circuit, its condition matters as much as the fuse it's connected to. This is the genuine Rinnai fuse harness for the 1500E/1200E, made to the original specification. Where the existing harness has degraded or failed, replacing it with the genuine part restores that safety signal path properly, keeping the appliance's overheat protection working as designed rather than relying on a compromised connection. ⚠ Important: This part must be installed by a qualified technician familiar with Rinnai products. Tur