FREE Air Conditioning Repair Refrigerant Recovery and Charging Questions and Answers

Question 1

Which of the following refrigerants requires a dedicated recovery machine and recovery tank due to its high flammability and specific handling procedures?

Accepted Answer

R-290 (Propane)

Answer

R-410A

Answer

R-134a

Answer

R-22

Question 2

During a refrigerant recovery process, the technician observes that the recovery machine's compressor cycles on and off frequently, and the pressure in the system is not decreasing as expected. What is the most likely cause of this issue?

Accepted Answer

The recovery machine's filter-drier is clogged.

Answer

The recovery tank is overfilled.

Answer

The system being recovered has a significant leak.

Answer

The manifold gauge hoses are too short.

Question 3

When charging a system with a zeotropic refrigerant blend (e.g., R-407C), why is it crucial to charge the refrigerant into the system as a liquid?

Accepted Answer

To prevent 'fractionation' and maintain the correct blend composition.

Answer

To ensure the system reaches its target superheat faster.

Answer

To avoid damaging the compressor with liquid refrigerant.

Answer

To minimize the risk of pressure spikes during charging.

Question 4

A technician is preparing to recover refrigerant from a residential split-system air conditioner. Before connecting the recovery machine, what is the FIRST critical step they should take to ensure a safe and effective recovery?

Accepted Answer

Verify the recovery tank has sufficient capacity and is not overfilled.

Answer

Purge the recovery hoses with nitrogen.

Answer

Evacuate the system with a vacuum pump.

Answer

Check the system for leaks using an electronic leak detector.

Question 5

What is the primary purpose of performing a deep vacuum (e.g., to 500 microns or less) on an HVAC system after refrigerant recovery and before recharging?

Accepted Answer

To ensure all non-condensable gases and moisture are removed from the system.

Answer

To prevent the new refrigerant from reacting with residual oils.

Answer

To facilitate faster charging of the new refrigerant.

Answer

To test the system for micro-leaks that a pressure test might miss.

Question 6

A technician is charging a new R-410A system by weight using a charging scale. The system specifications call for 6 lbs 8 oz of refrigerant. The ambient temperature is 85°F (29°C). What is the most accurate method to ensure the correct charge is added?

Accepted Answer

Weigh the refrigerant cylinder before and after charging to ensure the specified amount is transferred.

Answer

Charge until the suction pressure matches the manufacturer's pressure chart for 85°F ambient.

Answer

Charge until the superheat and subcooling values match the manufacturer's specifications.

Answer

Fill the system until the liquid line sight glass runs clear.