Applied Methods and Techniques Flashcards

When using system-dependent (passive) recovery on a small appliance with an inoperative compressor, what helps recover the most refrigerant?

Answer: Accessing both the high and low sides and heating and tapping the compressor

Two access points plus heating and tapping the compressor frees refrigerant trapped in the oil, which improves recovery.

For a small appliance with an operating compressor, how much refrigerant must be recovered with equipment made after November 15, 1993?

Answer: 90% of the charge, or a 4 in. Hg vacuum

Type I rules require 90% recovery (80% if the compressor does not run) or a 4 in. Hg vacuum.

Why shouldn't solderless piercing-type access valves be left on small appliances permanently?

Answer: They tend to leak over time

Piercing valves tend to leak, so they should be used only temporarily.

Before recovering refrigerant from a small appliance, what should a technician do first?

Answer: Identify the refrigerant type, for example from the nameplate

Knowing the refrigerant avoids mixing it in the recovery cylinder and shows whether a substitute or hydrocarbon may be present.

If a technician finds an unexpected substitute refrigerant (such as a hydrocarbon) in a small appliance, what is the correct action?

Answer: Follow the manufacturer's or substitute's instructions and avoid mixing it with other refrigerants

Unknown or flammable substitutes need special handling and must never be mixed into standard recovery cylinders.

What is the main purpose of the filter-drier in a recovery unit?

Answer: To remove moisture, acid, and particles from recovered refrigerant

Filter-driers trap contaminants so cleaner refrigerant goes to the cylinder and the recovery unit is protected.

After a compressor burnout, what should a technician check the oil for?

Answer: Acid contamination

A burnout forms acids that must be found and cleaned out, for example with acid-removing filter-driers, to protect the new compressor.