In a system with varying branch pressures, what would be the calibration point of a thermostat with a spring range of 3-8 psig?

The calibration point of a thermostat with a spring range of 3-8 psig is the maximum pressure that the thermostat is designed to respond to, which is 8 psig. This upper limit indicates the point at which the thermostat will break the circuit or trigger other actions in the control system.

When thermostats are calibrated, they are set to operate efficiently within a specified range. In this case, the range represents that the thermostat will have a functional response to pressures starting from 3 psig up to 8 psig. The actual calibration point where the device would increasingly exert control is naturally pegged to the higher end of the spectrum. This ensures that it can respond appropriately even as pressures fluctuate within the system.

Setting the calibration point at the higher value also ensures that the equipment operates safely and effectively, as it assures that the system doesn't exceed upper pressure limits that could lead to potential failures or safety issues. Therefore, focusing on this maximum range is crucial for operational reliability and safety.