What is the likely explanation?

Recovery techniques · EPA 608 Type I. The correct answer, and the reasoning behind it.

Identifying refrigerants, access valves, passive recovery and solderless fittings.

The question

A dehumidifier labeled R-410A has been off for hours at 70 °F. Its pressure reads well above the chart value for R-410A at 70 °F. What is the likely explanation?

• AIt holds air or a different refrigerant than labeledCorrect answer
• BIt is undercharged and has lost most of its refrigerant
• CIts compressor has failed
• DIts capillary tube is restricted

Why “It holds air or a different refrigerant than labeled” is correct

At rest, a system with liquid refrigerant should sit at the saturation pressure for its temperature. A pressure well above the chart value means something else is adding pressure: air or other noncondensables, or a refrigerant other than the one labeled.

Source: EPA: Test Topics

Why the other answers are wrong

• It is undercharged and has lost most of its refrigerant — An undercharged system reads at or below the chart pressure, not above it.
• Its compressor has failed — With the unit off and settled, a dead compressor does not raise the standing pressure.
• Its capillary tube is restricted — Once the unit has been off for hours, pressure equalizes through the restriction.

Practice more of this

More EPA 608 Type I practice questions, or see every EPA 608 practice test.