How is a pressure switch tested for defects?

Testing a pressure switch for defects requires evaluating its functionality without applying power to it, which ensures safety and accuracy. The correct approach involves connecting a meter across the switch while the power is off in order to assess its continuity and operation. This method allows a technician to confirm whether the switch opens and closes properly under the expected pressure conditions, helping to identify any faults like sticking or failure to actuate when pressure levels are reached.

Measuring voltage across the switch while it’s powered might not provide a complete assessment of its functionality, as it does not test whether the switch is working correctly in response to pressure changes. Similarly, applying direct current to the switch could risk damage to the component, as pressure switches are designed to operate under specific conditions rather than being energized directly in a way that, in essence, bypasses their intended function.

Using a pressure gauge to measure resistance is not applicable because resistance measurement typically requires power and doesn’t give an accurate picture of the switch's operational status under pressure conditions. Therefore, the chosen method of connecting a meter across the switch with power off stands out as the most effective and safe way to test for defects.