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

Type III certification covers low-pressure systems — large commercial and industrial chillers that use refrigerants such as R-11, R-113, and R-123 (HCFC-123). These refrigerants have saturation pressures below atmospheric pressure at normal operating temperatures, meaning the systems operate under vacuum. This unique characteristic requires special training and handling procedures.

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

Low-pressure refrigerants like R-11 and R-123 have atmospheric boiling points well above typical evaporator temperatures. At evaporator temperatures (35-45°F), these refrigerants would be below their normal boiling point, creating pressures below 14.7 psia (below atmospheric). This means the system operates in a vacuum on the low side, so air and moisture can be drawn in through any leaks rather than refrigerant leaking out.

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

Because low-pressure chillers operate below atmospheric pressure, any leak allows air and moisture to be drawn into the system rather than refrigerant escaping outward. Air in a chiller system reduces capacity, raises condenser pressure, and causes purge unit operation. Moisture creates acid that corrodes system components. Regular purge unit operation and leak tightness are critical for low-pressure chiller performance.

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

The purge unit on a centrifugal chiller continuously removes non-condensable gases (primarily air and nitrogen) that infiltrate the low-pressure system through leaks. The purge unit separates the air from refrigerant vapor, releases the air to atmosphere while recovering the refrigerant. Excessive purge unit operation is a sign of refrigerant leaks or air infiltration.

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

For low-pressure systems with charges over 200 lbs, the EPA requires recovery equipment to achieve 25 millimeters of mercury absolute pressure (25 mmHg or approximately 25 Torr absolute). Since low-pressure systems already operate in a vacuum, the recovery standard is expressed in absolute pressure rather than vacuum depth. This extremely low absolute pressure ensures maximum refrigerant recovery.

EPA 608 609 Practice Test

EPA 608 609 Practice Test

EPA 608 Type III Practice Test 2