🔍 Key Concepts

• Behavior of a TXV (thermostatic expansion valve) when the system is overcharged with refrigerant • Effects of excessive head (high-side) pressure on compressor controls and safety devices • Difference between a pressure cutout control and a pressure relief valve

💭 Think About

• Think about what happens to the high-side pressure when there is too much refrigerant in the system and how the compressor’s controls would react to that. • Ask yourself: which of these signs would be seen repeatedly in normal operation, and which would be an emergency / last-resort condition? • Consider which option is most closely linked to a high-pressure safety control doing its job, versus a mechanical safety device that should almost never operate.

✅ Before You Answer

• Identify which choice involves a safety control switch (automatic stopping/starting) rather than a mechanical relief device. • Recall that a relief valve lifting indicates a dangerously abnormal condition, not just an overcharge under normal operation. • Match the symptom that best fits a system where the high-pressure side is frequently exceeding its cutout setting because of too much refrigerant.