The coil temperature measured at the expansion valve sensing bulb of an operating system is 10°F. The low side pressure with the compressor running as shown on the gauge illustrated indicates 15 psig. What adjustments or changes, if any, should be made to the system? GS-RA-16

Correct Answer: Option C — The expansion valve should not be adjusted, as the degree of superheat is within the accepted range.

At 15 psig, R-134a or common marine refrigerants yield a saturation temperature that, when subtracted from the 10°F bulb reading, falls within the standard 8°F to 12°F operational superheat window.