What might happen if the regulator vent becomes blocked with dirt?

When the vent of a regulator becomes blocked with dirt, it can interfere with the regulator's ability to sense the pressure of the gas accurately. The primary function of the vent is to allow the regulator to maintain consistent pressure by sensing changes in ambient and gas pressure. If the vent is blocked, the regulator may become unable to respond properly to changes in gas flow, which can lead to a condition known as "locking up." This means the regulator will fail to adjust the pressure as needed, potentially resulting in the equipment receiving too much or too little gas pressure.

In this scenario, while the other outcomes could also be possible depending on the severity of the blockage and the system design, the primary consequence of a blocked regulator vent is that the regulator would become unresponsive, or "locked up," preventing it from functioning correctly. Hence, the regulator being unable to adjust properly is a direct result of the vent blockage.