Copeland 918 0002 03 Crankcase Heater Els PW 17895 matching the correct orifice size matching the correct orifice size is vital to prevent over pressurization and ensure the internal relief valve (IRV) functions within its design parameters Proper installation of this internal high limit switch is essential for maintaining the safety sequence of operation and protecting the primary heat exchanger from excessive thermal stress Technicians should perform a resistance (ohm) check across the leads or use an amp probe during the off cycle to ensure the 100 watt element is drawing current Please contact our team to confirm compatibility or technical details before purchasing