Grisbi

Hi Everyone, I am new to this forum and I am learning about my westco electric furnace. I don't know the age but it must be over 30 years. 40? Anyway I have a fan switch with a bimetal part that actuates the cutoff for the furnace. At least I think thats how it works. Its a Honeywell L4069C1009. I tested the connections for continuity and the circuit is closed when I manually actuate the bimetal switch. It was removed by a technician who said it needs to be replaced. Is there a standard part that can replace this item? How do I test the original part to see if it is broken. Sorry for the long post but I am new to this. Thanks.