EPA 608 Type III Practice Test 2

Question 1

EPA Section 608 Type III certification is required for technicians servicing which type of equipment?

Accepted Answer

Low-pressure systems such as centrifugal chillers using R-11 or R-123

Answer

Small appliances with hermetically sealed compressors

Answer

High-pressure systems such as R-410A split systems

Answer

Motor vehicle A/C systems using R-134a

Question 2

Why do low-pressure chiller systems (Type III) operate under vacuum rather than under pressure?

Accepted Answer

Because their refrigerants have boiling points above typical evaporator temperatures, so evaporator pressure is below atmospheric

Answer

To improve compressor efficiency at large tonnage

Answer

To prevent refrigerant from venting if there is a leak

Answer

Because their refrigerants are too toxic to be stored under pressure

Question 3

What is the most significant contamination risk specific to low-pressure chiller systems?

Accepted Answer

Air and moisture infiltration through vacuum-side leaks

Answer

Refrigerant oil mixing with compressor lubricant

Answer

High-side refrigerant blending with low-side refrigerant

Answer

Corrosion from halide ions at high operating pressures

Question 4

What does the purge unit on a centrifugal chiller do?

Accepted Answer

Removes non-condensable gases (air) and moisture that have entered the chiller system

Answer

Removes refrigerant from the system before compressor startup

Answer

Purges lubricating oil from the refrigerant circuit

Answer

Releases pressure if system pressure exceeds the safety limit

Question 5

For a Type III low-pressure system with a charge of more than 200 lbs, what recovery efficiency is required using equipment made after November 15, 1993?

Accepted Answer

System must reach 25 mmHg absolute (25 Torr)

Answer

90% of charge must be recovered

Answer

System must reach 29 inches of mercury vacuum

Answer

System must reach 25 inches of mercury vacuum

Question 6

R-123 (HCFC-123) has which safety classification under ASHRAE Standard 34?

Accepted Answer

B1 (no flame propagation, higher toxicity)

Answer

A1 (no flame propagation, lower toxicity)

Answer

A2L (mildly flammable, lower toxicity)

Answer

B2L (mildly flammable, higher toxicity)