After isolating the condenser for non-condensable detection, what is the next step?

The correct choice involves letting the condenser settle and reach ambient temperature after isolating it for non-condensable detection. This step is essential because allowing the condenser to reach the same temperature as its environment ensures that any non-condensable gases present can be properly identified by their effect on pressure readings.

When the condenser achieves ambient temperature, it stabilizes, allowing technicians to accurately assess the system's pressure without the influence of temperature changes that may complicate the readings. This is vital for precisely determining whether non-condensables are present, as they can significantly affect the performance and efficiency of the HVAC system.

Applying heat to the condenser could artificially elevate pressures and interfere with identifying non-condensable gases. Connecting a vacuum pump prematurely would not yield accurate results regarding the presence of non-condensables and could draw any potential gas into the pump. Opening the condenser for immediate assessment without proper cooling could lead to improper diagnosis and potential system issues. Thus, allowing the condenser to settle is the most logical and effective next step in this diagnostic process.