Honeywell Thermostat control Pneumatic type with Part no. TP9371004-1?

Question

this thermostat oprating with pneumatic sending signal to mixing box thru pressure and activate the actuator gradually.

Answer 1

You didn't ask a question.
This is a very old style of system. One of the regular maintenance tasks is to clean the dust out of these. Also, the back of the metal strip which rests over the air outlet should be cleaned of any grease or grime that collects on it. Also, make sure the air pump is delivering enough pressure to the system and that there are no leaks in the lines leading to the thermostat. Consider replacing this with a digital programmable thermostat in the future.