EPA 608 Type II Practice Test 2 — Questions and Answers
Question 1: What is the recovery requirement for a Type II system with a full charge of less than 200 lbs, using recovery equipment manufactured after November 15, 1993?
- Evacuate to 0 psig
- Evacuate to 4 inches of mercury vacuum (Correct answer)
- Evacuate to 10 inches of mercury vacuum
- Evacuate to 15 inches of mercury vacuum
Correct answer: Evacuate to 4 inches of mercury vacuum
For Type II systems with a refrigerant charge of less than 200 lbs, EPA requires recovery until the system reaches at least 4 inches of mercury (Hg) vacuum using certified equipment made after November 15, 1993. Systems with charges over 200 lbs require a deeper 15 Hg vacuum. Proper evacuation levels ensure maximum refrigerant capture before opening the system.
Question 2: In a Type II refrigeration system, what is superheat and why is it important?
- The temperature of the discharge gas above ambient; it indicates condenser efficiency
- The temperature rise of suction gas above its saturation temperature; it ensures only vapor enters the compressor (Correct answer)
- The difference between supply and return air temperatures across the coil
- The number of degrees the refrigerant must be cooled in the condenser
Correct answer: The temperature rise of suction gas above its saturation temperature; it ensures only vapor enters the compressor
Superheat is the temperature of the suction gas above its saturation (boiling) point at a given pressure. Proper superheat ensures that all refrigerant has fully evaporated before entering the compressor, preventing liquid refrigerant from reaching the compressor (liquid slugging). Insufficient superheat risks compressor damage; excessive superheat reduces system efficiency.
Question 3: A rooftop unit charged with R-410A shows high subcooling at the liquid line. What does this most likely indicate?
- The system is undercharged with refrigerant
- The expansion valve is overfeeding refrigerant
- The system is overcharged with refrigerant (Correct answer)
- The condenser fan motor is running too fast
Correct answer: The system is overcharged with refrigerant
High subcooling (liquid refrigerant cooled significantly below saturation temperature) typically indicates an overcharged system. Excess refrigerant floods the condenser, increasing the liquid subcooling. Undercharge typically causes low subcooling and high superheat. Diagnosing subcooling and superheat together is the proper method for evaluating charge level in high-pressure systems.
Question 4: What is the function of a crankcase heater on a Type II reciprocating compressor?
- To keep the compressor oil warm during the off-cycle, preventing refrigerant migration into the oil (Correct answer)
- To preheat suction gas to increase compression efficiency
- To maintain oil viscosity during high-load summer operation
- To prevent condensate from forming inside the motor windings
Correct answer: To keep the compressor oil warm during the off-cycle, preventing refrigerant migration into the oil
During the compressor off-cycle, refrigerant can migrate to the crankcase and dissolve into the compressor oil, creating a refrigerant-oil mixture. When the compressor starts, this mixture can flash (boil rapidly), causing oil foaming, liquid slugging, and bearing damage. The crankcase heater keeps oil warm enough to prevent refrigerant migration, protecting the compressor during startup.
Question 5: When using a manifold gauge set on a Type II high-pressure system, what does a higher-than-normal suction pressure combined with lower-than-normal discharge pressure most likely indicate?
- System overcharge with refrigerant
- Compressor valve failure (worn or broken valves) (Correct answer)
- Refrigerant leak on the suction side
- Condenser coil fouling with debris
Correct answer: Compressor valve failure (worn or broken valves)
High suction pressure combined with low discharge pressure is a classic sign of compressor valve failure. Worn or broken compressor valves allow refrigerant to bypass from the high side back to the low side, reducing compression efficiency. The compressor cannot build proper pressure difference, resulting in high suction / low discharge readings and poor cooling performance.
Question 6: Under EPA Section 608, which of the following is NOT required information in the service record for a system with over 50 lbs of charge?
- Amount of refrigerant added at each service visit
- Name and certification number of the technician
- Manufacturer's serial number of the recovery machine used (Correct answer)
- Date of each service involving refrigerant addition
Correct answer: Manufacturer's serial number of the recovery machine used
EPA Section 608 service records for systems with more than 50 lbs of refrigerant must include: the quantity of refrigerant added at each service, the date of service, and the name of the certified technician. The serial number of the recovery machine is not a required record element, though technicians must use certified equipment. Records must be kept for 3 years.
EPA 608 Type II Practice Test 2
What is the recovery requirement for a Type II system with a full charge of less than 200 lbs, using recovery equipment manufactured after November 15, 1993?