Correct 1920 thermostat temp ?

[Jlw4141]

What is the recommended temp for the tstat? i see NH list a 160f 180f 190f so not sure which one i should runs in here PA.. thanks!

 

[Roadworthy]

There may be a temperature stamped on the original. Lacking that information I'd probably go with 180, myself. That's the one in the middle of the ranges you offered. I think it's also the most common.