🔍 Key Concepts

• How different mechanical problems in compressors create different types of sounds (squeal vs. hiss vs. knock) • What an unloader does during compressor startup and how failure might sound • How drive belt tension (too loose vs. too tight) affects noise and wear

💭 Think About

• Which of these faults would most likely create a high-pitched squealing sound specifically at the moment of starting? • Which options would more likely cause loss of pressure or leakage rather than a distinct squeal? • Think about which parts are moving relative to each other in a way that could slip or rub and make a squeal when the motor first comes under load.

✅ Before You Answer

• Focus on the word squealing – high-pitched friction/slip noise, not a leak or knock • Note the timing: the question says upon starting, not during normal running • Ask yourself which component, if improperly adjusted, would cause excessive friction or slipping exactly when the compressor first loads up