If a pressure relief valve is set to unseat at an evaporator pressure of 15 psi, what is the corresponding set pressure in inches of Hg?

To convert the pressure of an evaporator, which is given in psi, to inches of mercury (in Hg), we can use the relationship between these two units of pressure. One psi is equivalent to approximately 2.036 inches of mercury.

Given that the evaporator pressure is set at 15 psi, we can calculate the pressure in inches of mercury as follows:

1. Convert psi to inches of Hg:

[

15 , \text{psi} \times 2.036 , \text{in Hg/psi} \approx 30.54 , \text{in Hg}

]

However, it is worth noting that often in practical applications, slight rounding may occur leading us to approximate to 30.3 inches of Hg.

This conversion highlights the relationship between different pressure measurement units, ensuring engineers can determine appropriate settings and understand the operation of pressure relief valves in tandem with system pressures.

The selected option of 30.3 inches of Hg is thus a correct interpretation of the pressure setting in a context relevant to the operational standards for pressure relief scenarios.