Pneumatic thermostats are still very much in use. Unless you have been around for a while and calibrated one of these devices, they can be a bit time consuming to figure out. The biggest thing to get past is the vocabulary involved. What one vendor calls “proportional band” another calls ” % authority”. Remember these things were state of the art technology when Don Draper and the boys from the TV show Mad Men had three martini lunches and got paid lots of money to make up words to call things.
So if you find yourself having to calibrate a pneumatic thermostat my first tech tip is : DO NOT READ THE INSTRUCTION SHEET. Just remember this video from Jerry Condiff. Jerry is a pneumatic controls trainer, who has calibrated more pneumatic thermostats than the total of all the drinks the MAD Men of the fifties drank not just at lunch put dinner too. Thanks Jerry.