it is likely not detecting a flame

Industrial Build: Features a moisture-resistant Class F insulation rating and internal thermal protection for long-term reliability in the field

How do I change the ARD5TZ to a power-open configuration

depending on the run-time of the blower and the ambient dust load of the environment

63-inch diameter shaft

Robertshaw 5500-213M Switch 318973-401 it is likely not detectingThe Robertshaw 5500 213M Infinite Switch is a heavy duty, voltage sensing replacement control engineered for precision management of resistive loads in industrial and commercial heating equipment. As a direct M Series 240V infinite switch upgrade, this unit replaces the discontinued VSI (INF) models and the Robertshaw 5500 213. It features a 22. 5% low end input capability, making it ideal for applications requiring consistent, proportionate heat