Hot Blast furnace, problem with fan switch

[Dana987]

My friend has a Hot Blast furnace and the guy who did the wiring burnt up the automatic fan switch button. I took the 5 inch probe bimetal type switch off the old furnace and installed it and it worked fine for 2 years till my friend started messing with it and the blowers ran nonstop. They bought a new automatic fan switch button and I put it on and they started a fire last night and the blowers cycle off and on all the time running a few seconds and off a few seconds. I wired it so the hot wire ran thru the switch then to the blower motors. Is it wired correctly?
Thanks for any help.
Dana

 

[Indianadave]

My friend has a Hot Blast furnace and the guy who did the wiring burnt up the automatic fan switch button. I took the 5 inch probe bimetal type switch off the old furnace and installed it and it worked fine for 2 years till my friend started messing with it and the blowers ran nonstop. They bought a new automatic fan switch button and I put it on and they started a fire last night and the blowers cycle off and on all the time running a few seconds and off a few seconds. I wired it so the hot wire ran thru the switch then to the blower motors. Is it wired correctly?
Thanks for any help.
Dana

I'm sure this has already been corrected but, was wondering if the high and low limits may have been adjusted too close together?

 

[Dana987]

I'm sure this has already been corrected but, was wondering if the high and low limits may have been adjusted too close together?

The ole boy fired his furnace up again a few days later and the button type fan switch worked fine and has ever since. I thought it was wired correctly. Apparently the switch just needed to get hot and cool off before it started working right.