If you want to maintain 12 PSI in the boiler, to what pressure will you have to adjust the operating pressure switch to open?

To maintain a consistent operating pressure of 12 PSI in a boiler system, the operating pressure switch must be adjusted to open at a setting that allows the system to cycle on and off effectively. Typically, the pressure switch is set to open at a lower pressure than the desired operating pressure, creating a buffer that allows the system to regulate itself without constant operation.

Setting the operating pressure switch to open at 8 or 9 PSI is effective because it provides enough of a differential from the operating pressure of 12 PSI. This ensures that when the pressure drops to that range, the boiler will kick in and generate more steam to reach the desired 12 PSI. This strategy helps to achieve stable operation, prevents unnecessary wear on the boiler from constant cycling, and improves overall efficiency.

In contrast, if the operating pressure switch was set to open at a higher pressure (such as 10 or 11 PSI), it would mean that the boiler would not engage until the pressure was almost at the desired level, making the system less efficient. Similar logic applies to the other choices, as opening at significantly lower pressures (5 or 6 PSI) may not allow for adequate steam production within the operational range required for effective cooking and heating in commercial applications.