What does 'Open on Rise' mean for this furnace limit

or a clogged filter causing the plenum temperature to exceed the 220°F threshold

check for continuity across the switch terminals

As part of the SKF Explorer range

Spence Engineering 05-05003-00 Orange Spring What does 'Open on Rise'The Spence Engineering 05 05003 00 Orange Spring is a critical component for technicians maintaining Spence D Pilot and D5 pressure reducing pilots. Designed for high performance steam and fluid systems, this orange adjusting spring provides a precise delivery pressure range of 5 50 PSI. Built with a 1 4 inch wire diameter, it ensures consistent tension and reliable set point stability when integrated into a Spence Type E or Type C main valve