4 Recovering Refrigerant from Low-Pressure Appliances Free Online FlashCards

Why can air and moisture enter a low-pressure appliance?

Low-pressure appliances operate below atmospheric pressure in parts of the refrigeration cycle, so air and moisture can leak inward.

What recovery equipment is suitable for a low-pressure appliance?

Use recovery equipment certified for the appliance and suitable for its refrigerant and operating conditions. Follow the machine’s instructions, pressure limits, and high-pressure cutout requirements.

What must you avoid when filling a recovery cylinder?

Identify the refrigerant before connecting equipment, and do not mix refrigerants in a recovery cylinder.

How should a recovery cylinder be positioned and filled?

Keep the cylinder upright and secured, use a scale while filling, and never exceed its marked maximum gross weight or applicable filling limits.

What Section 608 certifications generally apply to covered appliances?

EPA Section 608 generally requires certified recovery or recycling equipment for covered appliances, and technicians need the applicable Section 608 certification to service them.

In what order should refrigerant phases be recovered?

Recover accessible liquid first, then recover vapor. Follow the specified valve sequence and do not bypass safety controls.

How can you prevent chiller water tubes from freezing during evacuation?

Circulate water through the chiller or drain it as the equipment instructions require. This helps prevent water in the tubes from freezing as refrigerant pressure and temperature fall.

Why may refrigerant remain in chiller oil, and what can reduce its release?

Oil can retain dissolved refrigerant. EPA Section 608 test guidance notes that heating oil to about 130°F before removal reduces refrigerant release.

What pressure limit applies before opening for an oil change?

Before opening the appliance or isolated portion for an oil change, evacuate or pressurize it to no more than 5 psig. Alternatively, drain the oil into a system receiver brought to that pressure.

What is the standard evacuation target for a low-pressure appliance?

The standard evacuation target for a low-pressure appliance is 25 mm Hg absolute, regardless of whether the recovery equipment was made before or after November 15, 1993.

What can a pressure rise after evacuation indicate?

Verify pressure with an appropriate gauge, wait several minutes, and check for a rise. Rising pressure can mean refrigerant remains as liquid or is boiling out of oil; continue recovery as needed.

When may recovery be limited to an isolated appliance section?

EPA allows recovery from an isolated section when the refrigerant can be isolated to a system receiver.