What is the operating pressure stated for the boiler in the example?

• A. 100 psi
• B. 150 psi
• C. 135 psi
• D. 200 psi

Answer: (C)

Operating pressure is the steady pressure the boiler is designed to run at during normal operation. In the example, the boiler’s operating pressure is one hundred thirty-five psi, meaning the controls are set to maintain about that level under typical demand. This value guides how the boiler is operated, how the gauge should read during normal firing, and how safety devices are configured. It’s distinct from the maximum allowable working pressure, which is the upper limit the vessel can safely handle, and from the relief valve setting, which is set to prevent exceeding that limit. Other numbers would indicate different operating conditions not specified in the example, so the stated value of one hundred thirty-five psi is the one that matches the scenario.