EPA 608 609 System Evacuation and Charging Procedures 2

Question 1

How must a blended (zeotropic) refrigerant be added to a system during charging?

Accepted Answer

As liquid only

Answer

Zeotropic blends like R-410A and R-404A must be charged as liquid to prevent fractionation, which would alter the blend's composition and performance.

Question 2

What does the blue (low-side) gauge on a manifold gauge set measure?

Accepted Answer

Low-side suction pressure

Answer

The blue gauge measures low-side (suction) pressure, which corresponds to the evaporator pressure and is used to assess evaporator conditions.

Question 3

When charging a single-component refrigerant into an operating system, in what state should it enter the suction line?

Accepted Answer

Vapor (gas) only

Answer

Single-component refrigerants like R-22 can be safely charged as vapor into the suction line of a running system without risk of slugging the compressor.

Question 4

What does measuring superheat help a technician determine when charging a system with a fixed-orifice metering device?

Accepted Answer

Proper refrigerant charge level

Answer

In fixed-orifice systems, suction line superheat directly reflects the refrigerant charge level — too high indicates undercharge, too low indicates overcharge.

Question 5

When using the subcooling method to verify charge in a TXV system, where is the liquid line temperature measured?

Accepted Answer

At the liquid line near the condenser outlet

Answer

Subcooling is measured at the liquid line leaving the condenser, comparing actual temperature against saturation temperature at the measured high-side pressure.

EPA 608 609 Practice Test

EPA 608 609 Practice Test

EPA 608 609 System Evacuation and Charging Procedures 2