2 Evacuation Levels and Verification Free Online FlashCards

What does an appliance evacuation endpoint specify?

An evacuation endpoint is the required refrigerant recovery level before an appliance is opened or disposed of; it is not the deeper vacuum used to dehydrate a repaired system.

What does a higher in. Hg vacuum reading indicate?

In. Hg vacuum is measured relative to standard atmospheric pressure of 29.9 in. Hg. A higher vacuum reading means lower system pressure.

What endpoint applies to very-high-pressure appliances?

Both use a target of 0 in. Hg vacuum, whether the recovery equipment was made before or on or after Nov. 15, 1993.

What endpoint applies to high-pressure appliances charged with less than 200 lb?

Both use a target of 0 in. Hg vacuum, regardless of whether the recovery equipment was made before or on or after Nov. 15, 1993.

What endpoint applies to high-pressure appliances charged with 200 lb or more?

The target is 4 in. Hg vacuum for equipment made before Nov. 15, 1993, and 10 in. Hg vacuum for equipment made on or after that date.

What endpoint applies to medium-pressure appliances charged with less than 200 lb?

The target is 4 in. Hg vacuum for equipment made before Nov. 15, 1993, and 10 in. Hg vacuum for equipment made on or after that date.

What endpoint applies to medium-pressure appliances charged with 200 lb or more?

The target is 4 in. Hg vacuum for equipment made before Nov. 15, 1993, and 15 in. Hg vacuum for equipment made on or after that date.

What evacuation level applies to low-pressure appliances?

The required level is 25 mm Hg absolute for either recovery-equipment manufacture date. This is absolute pressure, not 25 mm Hg vacuum.

Which appliance categories are excluded from the stationary-appliance table?

The stationary-appliance table excludes small appliances, MVACs, and MVAC-like appliances. Small appliances have separate recovery-percentage rules or a specified alternative endpoint.

Does 8 in. Hg vacuum meet a 10-in. Hg vacuum target?

No. If the target is 10 in. Hg vacuum, a reading of 8 in. Hg vacuum falls short; the gauge must reach at least the target before the appliance is opened.

What instrument is needed to verify a low-pressure appliance endpoint?

Use an instrument capable of measuring the required absolute pressure. An ordinary coarse compound gauge is not suitable for verifying the low-pressure endpoint.

What can a pressure rise during a rebound check indicate?

After reaching the target, isolate the appliance as appropriate and observe pressure. A rise may indicate refrigerant boiling from trapped liquid or coming out of oil; continue recovery and recheck.