When a technician needs to check the heating operation of a heat pump without gauge access ports, what should they do first?

Checking the temperature rise across the indoor coil is a fundamental step in assessing the heating operation of a heat pump, particularly when gauge access ports are not available. This method allows the technician to determine whether the heat pump is effectively transferring heat into the indoor space.

When measuring the temperature rise, the technician can take the inlet and outlet air temperatures of the indoor coil. By comparing these temperatures, it's possible to calculate the system's efficiency and effectiveness in providing heating. A significant temperature rise indicates that the heat pump is functioning properly and transferring thermal energy effectively.

In scenarios where gauge access is unavailable, this method becomes crucial as it provides immediate feedback on system performance. While it’s also important to consider factors like refrigerant levels, outdoor unit condition, and electrical components, those checks typically require additional steps or resources. Thus, measuring the temperature rise is the most straightforward and immediate way to evaluate heating performance under such circumstances.