this unit features a 150

spring-loaded solution engineered for mid-range commercial and industrial applications

A common failure point is the furnace igniting for 2-5 seconds and then shutting down

This specific model is rated for 0' to 1999'

Smith Vertex or Lochinvar Knight units

Aprilaire 4217 Scale Insert 340793-762 this unit features a 150The Aprilaire 4217 Scale Insert is a critical humidifier replacement part engineered to maintain the peak performance of your whole house humidification system. This plastic, U shaped scale control insert serves as a protective housing for the Aprilaire 10 water panel, ensuring that mineral deposits and scale accumulation are directed back into the evaporative pad rather than damaging the humidifier cabinet. Specifically designed for Aprilaire