Understanding Refrigeration Systems

What is the purpose of a compressor crankcase heater in a refrigeration system?

• To increase the refrigerant pressure

• To prevent refrigerant migration

• To cool the compressor

• To reduce oil viscosity

When should an oil sample be taken from a refrigeration unit?

• Only during routine maintenance

• When the unit is functioning normally

• After a leak or major component failure

• Every month

What is the recommended action after making a major repair to a refrigeration appliance?

• Flush the system with liquid refrigerant

• Dehydrate the appliance by evacuating to a minimum of 500 microns

• Operate the compressor immediately

• Add more refrigerant without checking for leaks

Why is it unlawful to flush field tubing with liquid refrigerant after a burn-out?

• It is too expensive

• It can cause environmental harm

• It is ineffective in cleaning the tubing

• It is a waste of refrigerant

What could happen if a hermetic compressor is operated with a vacuum in the system?

• The compressor will run more efficiently

• Electrical arcing could burn the terminals inside the compressor

• The refrigerant will freeze

• The oil will become too thick

What is the function of the gauge manifold set in HVACR?

• To measure the temperature of the refrigerant

• To measure system pressures

• To add oil to the compressor

• To clean the refrigerant lines

What color is the low-pressure, compound gauge on a gauge manifold set?

• Red

• Green

• Blue

• Yellow

What should be done to conserve refrigerant when servicing an appliance?

• Increase the refrigerant charge

• Find and repair leaks in the system

• Operate the system at higher pressures

• Use a larger compressor

Which of the following is NOT a reason to take a refrigerant oil sample?

• Suspected moisture in the system

• Routine maintenance

• Suspected acid formation

• Suspected oil sludge formation

What is the minimum evacuation level required for HFC refrigerants with POE oil after a major repair?

• 100 microns

• 500 microns

• 1000 microns

• 2000 microns