Thermostat
Specifications
TP970 Series
Maximum Safe Air Pressure:
25psi (172 kPa)
Maximum Safe AirTemperature: 150°F (66°C)
Throttling Range:
Gain:
2.5 psi/°F Adjustable
Operation
Pneumatic thermostats modulate output air pressure in response to room air temperature. Pneumatic thermo- stats fall into two categories: direct- acting or
Figure 3 graphically illustrates the relationship between room temperature and output pressure of a direct-acting thermostat.The graph in Figure 3 shows that as the room temperature increases, so does the output pressure of the thermostat.
Figure 3–Direct-Acting
Thermostat Response
Output Pressure
Input Temperature
Figure 4 illustrates the pressure/ temperature characteristics for a reverse-acting thermostat. As room temperature increases, the thermostat output pressure decreases.
Figure 4–Reverse-Acting
Thermostat Response
Output Pressure
Input Temperature
A thermostat in proper working order will be able to output a pressure ranging from approximately .5 psi to supply air pressure depending on distance from indicated setpoint.
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