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? Illustration GS-RA-16

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

At 15 psig, R-134a or R-22 saturation temperature is approximately -10°F to 0°F. Subtracting this from the 10°F bulb temperature yields a 10°F to 20°F superheat, falling squarely within acceptable marine operating parameters.