Download HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. and more Exams Nursing in PDF only on Docsity! HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. Are there drop-in replacements for R-12 systems? Why or why not? - Correct Answer No because the new refrigerants are incompatible with the oils and lubricants used in R-12 systems. What type of oil is used in R-134a and what oils will it mix with? - Correct Answer Ester based oils and they do not mix with other oils What type of lubricant is used with HCFCs? - Correct Answer Alkylbenzene lubricant What is difference b/w ternary blend a azeotropic blend? - Correct Answer Ternary blends are three-part mixtures whereas azeotropic blends are blends of two or more compounds that act like a single compound. What is the trait of a hygroscopic lubricant? - Correct Answer It absorbs (takes on) moisture HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. What is temperature glide and what type of blend won't have it? - Correct Answer Temp. blend is the difference between the dew point and the bubble point Dew Point - Correct Answer Occurs when saturation temp in evaporator causes refrigerant to change from liquid to vapor Bubble Point - Correct Answer Occurs when saturation temp in condenser changes refrigerant from vapor to liquid Will the gases in a ternary blend leak at the same rate? Why or why not? - Correct Answer No because different refrigerants in blend have different vapor pressures, causing them to leak at uneven rates Refrigeration Process - Correct Answer transfer of heat from one place to another HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. What are three Rs of refrigeration? - Correct Answer Recover, recycle, reclaim Recover - Correct Answer to remove any refrigerant in any condition from system and store in external container without necessarily testing or processing in any way Recycle - Correct Answer To clean refrigerant for immediate reuse by separating oil from refrigerant and removing moisture and acidity from refrigerant by use of products like filter driers Reclaim - Correct Answer To process refrigerant to level of new product specifications as determines by chemical analysis What standards must refrigerant recovery equipment meet and what components must all Type I and Type II refrigerant systems have? - HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. Correct Answer EPA-approved equipment testing organization. Service aperture or process stub System-Dependent Devices - Correct Answer Capture refrigerant with assistance of compressor and/or pressure of refrigerant in appliances from which refrigerant is being recovered Self-contained Devices - Correct Answer Have independent means to draw refrigerant out of appliances What is nitrogen and a filter-drier used for after recovery? - Correct Answer Use nitrogen to flush debris out of system after recovering refrigerant. Filter-drier should be installed to trap any debris that may cause damage to new compressor What must be done before starting an evacuation? - Correct Answer Recover all refrigerant and attain the mandated vacuum level HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. ASHRAE Standard 15-1994 - Correct Answer Requires refrigerant sensor that will sound alarm and automatically start ventilation system in occupied equipment rooms where refrigerant from leak will concentrate How often should refillable cylinders be hydrostatically tested? - Correct Answer 5 years What are the three ways you can control fill level of refillable cylinder? - Correct Answer Mechanical floats, electronic floats, or weight What is the EPA definition of a small appliance? - Correct Answer One that is manufactured, charged, and hermetically sealed in factory and contains five lbs. or less of refrigerant What standards must recovery equipment manufactured before Nov. 15th, 1993 meet? - Correct Answer Capable of recovering 80% of HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. What are two things that can cause high discharge pressures? - Correct Answer Not opening tank inlet valve or having excess air will cause higher discharge pressures How can you check if a tank contains excess air or non-condensables? - Correct Answer Check pressure inside recovery tank after allowing temp of cylinder to stabilize to room temperature What type of system can a vacuum pump be used on for recovery? - Correct Answer A vacuum pump can only be used on a recovery device in combination with a non-pressurized container and can not be used with self-contained recovery equipment (pressurized container) When using a system-dependent recovery system with an operating compressor, where should the refrigerant be recovered from? With a non-operating compressor? - Correct Answer When using a system- HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. dependent recovery process with an operating compressor, run the compressor and recover from the high side of the system. When using a non-operating compressor, it may be necessary to access both low and high side of system to achieve required recovery level and it will speed the recovery How can you release trapped refrigerants in the oil? - Correct Answer Necessary to heat and tap compressor with mallet several times or use vacuum pump How will activating a defrost timer aid in recovery process? - Correct Answer Help vaporize any trapped liquid refrigerant When should piercing type valves be used? What is a common problem with these valves? - Correct Answer Copper or aluminum tubing only. Tend to leak over time HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. What are some other small refrigeration systems that contain other types of refrigerants? Should these refrigerants be recovered with standard EPA equipment? - Correct Answer Ammonia, hydrogen or water and therefore, should not be recovered using current EPA- approved recovery devices. Similarly, systems built before 1950 may have methyl formate, methyl chloride, or sulfur dioxide as refrigerants and require special recovery equipment What should be done before charging a new system with refrigerant? - Correct Answer The unit should first be pressurized with NITROGEN (inert gas) and leak checked What are the leak repair requirements for comfort cooling appliances and commercial appliances containing 50 pounds or more of refrigerant? - Correct Answer The leak rate exceeds 15% in comfort cooling appliances The leak rate exceeds 35% in all commercial and industrial process refrigeration HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. with low-loss fittings, and meet stringent vacuum standards. System- dependent recovery equipment cannot be used on appliances containing more than 15lbs. of refrigerant How many inches of mercury vacuum is required for HCFC-22 appliances containing more than 200lbs. of refrigerant using equipment after Nov. 15th, 1993. - Correct Answer 0 Inches Hg What does the EPA consider major repairs? - Correct Answer Any maintenance, service or repair involving the removal or any or all of the following components: compressor, condenser, evaporator or an auxillary heat exchanger coil. What exceptions are there for evacuation for non-major repairs? - Correct Answer Repairs to leaky equipment: repairs to leaky equipment and non-major repairs HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. What can you do if you can't reach the required evacuation levels on leaky equipment? - Correct Answer Evacuate them to atmospheric pressure (0 psig) What steps are taken before using recovery equipment? - Correct Answer Check the service valve positions, check the oil level of the recovery unit, evacuate and recover any remaining refrigerant from the unit's receiver, and evacuate an empty recovery cylinder before transferring refrigerant to the cylinder. What types of hoses and couplings should be used during the recovery process? Why? - Correct Answer Use quick couplers, self-sealing hoses, or hand valves What common contaminants can be found in refrigerant oils? - Correct Answer Acids, moisture, and oil HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. What maintenance task should you take to help limit the damage of contaminated oils? - Correct Answer Check both the oil and filter on a refrigerant recycling machine as recovered refrigerants may contain acids, moisture, and oil. Use quick couplers, self-sealing hoses, or hand valves should be used to minimize refrigerant release when hoses are connected and disconnected Why might recovery equipment using hermetic compressors overheat? - Correct Answer Because the unit relies on the flow of refrigerant through the compressor for cooling If switching from recovering one refrigerant to another, what three steps must be taken before recovering the new refrigerant? What if the refrigerant is R-134A? - Correct Answer Purge the recover/recycle equipment by recovering as much of the first refrigerant as possible. Change the filter. Evacuate. Use special set of hoses for R-134A HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. clean and maintain efficiency. The purge unit removes air and moisture to prevent reduced condenser surface area, increased head pressure, compressor surge, increased pressure differential, and system corrosion. A high efficiency purge system will expel very little refrigerant along with the air. How does a centrifugal purge unit work? - Correct Answer A centrifugal purge unit takes its suction from the top of the condenser, removes the air from the system, and returns the refrigerant to the evaporator. What are three visible ways to check for leaks in a low pressure system? - Correct Answer Excessive running of a purge system, continuous excessive moisture in the purge unit could indicate a leak in the condenser or the chiller barrel, high lead pressure. HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. What needs to be done to leak check a low pressure system? - Correct Answer Increase the pressure in the system by use of controlled hot water or heater blankets. What can happen if you exceed 10 psig while pressurizing the system? - Correct Answer Can cause the rupture disc to fail How should a water box be leak tested? - Correct Answer Be certain water has been removed, then place the leak detector probe in through the drain valve. What equipment should be used to leak test a tube? - Correct Answer Hydrostatic tube test kit What are the leak repair requirements for comfort cooling appliances and commercial appliances containing 50lbs. or more of refrigerant? - Correct Answer The leak rate exceeds 15% in comfort cooling HVAC EPA 608 Certification Study Guide Exam with Correct & Verified Solutions. appliances or the leak rate exceeds 35% in all commercial and industrial process refrigeration What are the typical pressure settings for rupture discs on low pressure systems and recovery equipment? - Correct Answer The rupture disc on a low pressure system is set for 15 psig while the recovery unit's high pressure cut-out is typically set for 10 psig in order to help prevent damage to the low pressure How should a technician recover refrigerant from a system using R-11 or R-123? - Correct Answer Remove the liquid first and recover the remaining vapor After removal of liquid, about how much vapor will remain in the system on a 350 ton R-11 chiller? - Correct Answer 100lbs