In a residential steam-heating unit, how many pounds of pressure will trigger the pressure regulator to pop?

The pressure regulator in a residential steam-heating unit is typically designed to operate at a maximum pressure of 15 pounds per square inch (psi). When the pressure exceeds this threshold, the regulator activates to prevent further pressure build-up that could potentially lead to system failure or safety hazards.

Operating within these safety limits is crucial for both the performance and longevity of the steam-heating system, as well as for the safety of the occupants. The regulator is an essential component that helps maintain optimal operational conditions by ensuring that the pressure does not exceed the recommended limit, thus protecting the system from overpressure-related issues.

The other options represent pressures that are either too high or too low for typical residential steam systems, which is why they do not align with the standard operational parameters for pressure regulators in this context.