The Wayne 21854 features a 1/2 inch bore (shaft size)

this is a manual changeover thermostat

Is the reset manual or automatic

What is the thread size for the gas valve connection

it features a multi-switch relay design that supports staged heating control

Heil Quaker ICP 1192716 Pressure Switch Els PW 17895 The Wayne 21854 features aThe Heil Quaker ICP 1192716 Pressure Switch is a high altitude safety component designed for precision atmospheric monitoring in residential and commercial furnaces. As an OEM replacement for 1014826, this switch is critical for proving proper inducer motor draft before the ignition sequence begins. When operating at elevations above 2,000 feet, standard pressure switches may fail to close due to lower air density; the 1192716 HI ALT pressure switch