Why should the temperature inside the compressor be kept under 300°F?

Why should the temperature inside the compressor be kept under 300°F?

• A. To prevent motor windings from aging rapidly
• B. To avoid oil leaks from seals
• C. Because the compressor oil starts to break down above 300°F
• D. To ensure optimal refrigerant density

Answer: (C)

Oil temperature inside a compressor is critical because the oil must stay stable to properly lubricate, seal, and carry heat away from moving parts. When the oil gets too hot, it begins to break down chemically. Once it breaks down above around 300°F, its lubricating film becomes less effective and byproducts can form varnish or sludge. This leads to increased wear, poorer cooling, and a higher risk of compressor failure. Keeping the oil under 300°F preserves lubrication quality and overall reliability. The other options don’t fit as well: motor winding aging relates to insulation temperature, not oil breakdown; seals are more affected by seal materials and pressure than a fixed oil temperature; and refrigerant density is determined by the refrigerant’s own temperature and pressure, not the oil temperature.

Oil temperature inside a compressor is critical because the oil must stay stable to properly lubricate, seal, and carry heat away from moving parts. When the oil gets too hot, it begins to break down chemically. Once it breaks down above around 300°F, its lubricating film becomes less effective and byproducts can form varnish or sludge. This leads to increased wear, poorer cooling, and a higher risk of compressor failure. Keeping the oil under 300°F preserves lubrication quality and overall reliability. The other options don’t fit as well: motor winding aging relates to insulation temperature, not oil breakdown; seals are more affected by seal materials and pressure than a fixed oil temperature; and refrigerant density is determined by the refrigerant’s own temperature and pressure, not the oil temperature.