What pressure difference indicates a potentially faulty compressor in an HVAC system?

A potentially faulty compressor in an HVAC system can often be indicated by a scenario where there is no pressure on the low side. The low side of an HVAC system is where the evaporator operates, and adequate pressure is essential for the refrigerant to absorb heat and function effectively. If there is no pressure there, it suggests that the compressor might not be functioning correctly, possibly failing to draw in refrigerant or not compressing the refrigerant effectively.

This situation typically leads to inadequate cooling as the refrigerant cycle cannot proceed as intended. The absence of pressure indicates that the compressor may be unable to create the necessary pressure difference between the high and low sides, which hampers the overall performance of the system and could lead to further issues if not addressed promptly.

While other conditions such as high pressure on both sides or low pressure on both sides may indicate different issues with the system, the distinct absence of low side pressure particularly points to issues related to compressor operation. Fluctuating pressures might reflect other types of malfunctions or irregularities but still suggest that the compressor may not be operating efficiently.