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EPA 608 Type 3
Low pressure practice (test may include content from Core & Types 1/2)
| Question | Answer |
|---|---|
| Where would you place leak detector probe to check gas leaks into water box with water removed? | correct answer: in drain valve opening incorrect options: at rupture disc seal, around vent valve, around test plug |
| Which of following indicates air in low pressure system? | correct answer: high head pressure incorrect options: high liquid level, low head pressure, low suction pressure |
| Hydrostatic tube test kit is used to: | correct answer: determine if tube leaks incorrect options: blow all water out of tubes, remove water from machine, vent refrigerant into atmosphere |
| When leak testing low pressure centrifugal chiller with nitrogen, what is maximum test pressure? | correct answer: 10psig incorrect options: 0psig, 25psig, 50psig |
| Rupture disc on recovery vessel for low pressure refrigerants relieves at: | correct answer: 15psig incorrect options: 5psig, 10psig, 20psig |
| On low pressure chillers, moisture most frequently enters refrigerant system through: | correct answer: leaks from areas with gaskets or fittings incorrect options: air leaks in rupture disc assembly, tube leaks in evaporator, leaks from charging service valve |
| Excessive running of purge system on low pressure chiller generally indicates what condition? | correct answer: leaking system incorrect options: faulty air sensors, ambient temperature is too high, low purge unit efficiency |
| Pressure relief valves can only be installed: | correct answer: in parallel incorrect options: in series, vertically, horizontally |
| Where should discharge from rupture disc be piped for venting? | correct answer: outdoors incorrect options: to duct system, to evaporator, inside machinery room |
| What is primary purpose of purge unit on low pressure chiller? | correct answer: remove non-condensables from system incorrect options: remove refrigerant from system, condense air out of system, condense water out of system |
| Company uses chiller that diverts 55% of its cooling capacity to one of its manufacturing lines and 45% of its cooling capacity to air condition office spaces. Which leak rate category would this chiller be in? | correct answer: industrial process refrigeration (IPR) incorrect options: ice making refrigeration, commercial refrigeration, comfort cooling |
| Starting in 2019, what is leak rate threshold for commercial refrigeration equipment with full charge of 50 or more pounds of HCFC refrigerant? | correct answer: 20% incorrect options: 30%, 10%, 5% |
| Where does refrigerant go after it leaves purge unit of low pressure centrifugal system? | correct answer: evaporator incorrect options: condenser, compressor intercooler, recovery service vessel |
| To determine if system is leaking more than allowable rate, EPA allows use of which of following methods to determine full charge? | correct answer: use of calculations based on component and pipe sizes incorrect options: use of calculations based on power consumption in kWh, use of calculations based on compressor horsepower, use of calculations based on Btu capacity of system |
| ASHRAE Standard 15-1994 requires use of room sensors and alarms to detect: | correct answer: refrigerant leaks incorrect options: high levels of ozone, refrigerant contamination, excessive oxygen levels |
| Why do chillers using low pressure refrigerants require purge units? | correct answer: these systems operate below atmospheric pressure incorrect options: these systems require removal of contaminated refrigerant, purge units remove refrigerant from oil sump, these systems require removal of condensables from chiller |
| Why should oil be removed from low pressure system at 130 degrees F? | correct answer: less refrigerant will be contained in oil at higher temperature incorrect options: it is normal operating temperature for oil in low pressure system, warmer oil has lower viscosity and flows more easily, it shows that heater is working |
| EPA's leak repair requirements apply to appliances with charge size of: | correct answer: 50 pounds or greater incorrect options: 5 pounds or greater, 30 pounds or greater, 100 pounds or greater |
| What is meant by term "high efficiency purge unit?" | correct answer: purge units that discharge low percentage of refrigerant with air they remove incorrect options: discharge high % of refrigerant with air they remove, consume less than 5 watts of electrical power, contain less than 50 pounds of refrig. |
| During evacuation with large amounts of moisture, it may be necessary to increase pressure to counteract freezing with gas such as: | correct answer: nitrogen incorrect options: R-410A, R-22, air |
| Typical setting for high pressure cut-out control on recovery unit used for evacuating refrigerant from low pressure chiller is: | correct answer: 10psig incorrect options: 2psig, 5psig, 15psig |
| Chiller with charge of 200 pounds of ozone-depleting refrigerant has passed initial verification leak test. When must follow-up verification test be conducted? | correct answer: within 10 days incorrect options: same day, next day, within 30 days |
| Where is rupture disc located on centrifugal chiller? | correct answer: evaporator incorrect options: condenser, liquid line, economizer |
| Where is refrigerant added to centrifugal machine? | correct answer: evaporator incorrect options: condenser, liquid line, economizer |
| After all liquid has been removed from average 350 ton, low pressure appliance, approximately how much vapor refrigerant remains in system? | correct answer: 100 pounds incorrect options: 150 pounds, 350 pounds, 45 pounds |
| Low pressure chiller used for comfort cooling must be repaired if it has annual leak rate of _______ of total charge | correct answer: 10% incorrect options: 20%, 30%, 50% |
| If strong odor is detected during recovery process: | correct answer: compressor burnout may have occurred incorrect options: refrigerant is most likely R-717/ammonia, purge unit on condenser has opened, good indicator that R-123 is refrigerant being recovered |
| Where is refrigerant added to low pressure system during charging process? | correct answer: lowest access point on system such as evaporator charging valve incorrect options: access valve on purge unit entering condenser, lowest access point such as condenser charging valve, highest access point such as evaporator inlet valve |
| When charging low pressure system, refrigerant should be introduced to system as vapor to raise system's saturation temperature to minimum of: | correct answer: 36 degrees F incorrect options: 0 degrees F, 40 degrees F, 70 degrees F |
| During evacuation of systems with large amounts of water, it may be necessary to: | correct: increase pressure by introducing nitrogen (N2) to counteract freezing incorrect: purge cond. by removing N2 to encourage freezing, drain comp. by removing N2 to encourage freezing, decrease pressure by introducing N2 to counteract freezing |
| Because low pressure systems operate below atmospheric pressure (in vacuum): | correct: leaks in gaskets or fittings will cause air and moisture to enter system incorrect: unlikely to have air/moisture enter system, leaks in gaskets/fittings will cause substantial refrig. leaks, or oil clogging at condenser |
| In low pressure chiller, air and other non-condensables collect at: | correct answer: top section of condenser incorrect options: bottom of compressor, bottom of evaporator, header before metering device |
| Most efficient method of leak checking a charged low pressure refrigeration unit is to: | correct answer: pressurize system using controlled hot water or heater blankets incorrect options: pull 500 micron vacuum and hold for at least 12 minutes, pull 20" vacuum and hold for at least 24 hours, pull 29.9" vacuum and hold for at least 24 hours |
| Standard for machine room safety is: | correct answer: ASHRAE-15 incorrect options: ASHRAE-34, AHRI-740, EPA-740 |
| When installing more than one, pressure relief valves must be installed: | correct answer: in parallel with each other incorrect options: in series with each other, in system's suction line, on top of compressor head |
| EPA-required evacuation level for recovery or recycling equipment used on low pressure systems is: | correct answer: 25mm of Hg absolute incorrect options: 15 inches Hg, 20 inches Hg, 30 inches Hg absolute |
| When pressurizing a low pressure system for leak detection purposes, do not exceed: | correct answer: 10psig incorrect options: 5psig, 15psig, 20psig |
| What type of equipment can be worked on with Type III certification? | correct answer: low pressure incorrect options: high pressure, medium pressure, vacuum pressure |
| How long would equipment owner or operator have to retrofit or retire appliance that has exceeded threshold leak rate if replacement appliance uses 50 pounds or more of exempt refrigerant? | correct answer: 18 months incorrect options: 3 months, 12 months, 24 months |
| Which of following best describes refrigerant recovery process from low pressure system? | correct answer: start with liquid removal then switch over to vapor recovery incorrect options: start with vapor removal then switch to liquid, run comp. and only recover liquid refrig., run comp. and only recover vapor refrig. incorrect options: |
| What can be used to pressurize chiller system before opening system for non-major repair? | correct answer: controlled hot water incorrect options: nitrogen, R-409A, compressed air |
| Rupture disc on low pressure chiller has burst pressure of: | correct answer: 15psig incorrect options: 5psig, 10psig, 20psig |
| Where is purge unit located in low pressure system? | correct answer: top of condenser incorrect options: in lowest location, above shell, before oil separator |
| To repair chiller operating with R-22, technician: | correct answer: must have Type II certification (R-22 is high pressure refrigerant) incorrect options: does not need certification, must have Type I certification, must have Type III certification |
| Which of following refrigerants has safety classification of B-1? | correct answer: HCFC-123 (labeled as R-123 on top of P/T chart) incorrect options: CFC-11, CFC-12, HFC-134a |
| Which organization establishes refrigerant safety group standard? | correct answer: ASHRAE incorrect options: UL, AHRI, ASE |
| When leak testing low pressure chiller, maximum pressure to use is: | correct answer: 10psig incorrect options: 5psig, 15psig, 20psig |
| Owner must keep records of refrigerant added to low pressure system during service and maintenance if system charge is: | correct answer: 50 pounds or greater incorrect options: 25 pounds or greater, 100 pounds or greater, 150 pounds or greater |
| Under ASHRAE Standard 34, R-134a is classified as: | correct answer: A-1 (found on top of P/T chart) incorrect options: A-2, B-1, B-2 |
| Charged low pressure refrigeration system can be efficiently leak checked by: | correct answer: raising system pressure by heating with circulated hot water or heating blankets incorrect options: adding compressed air since it will be removed from system by purging unit, operating purge system, adding HCFC-22 |
| Existence of air in low pressure system causes: | correct answer: high head pressure incorrect options: low head pressure, low suction pressure, high liquid level |
| Which safety precaution should be adhered to for low pressure systems? | correct answer: all of above (do not siphon refrigerant by mouth, avoid spilling liquid refrigerant on skin, and use gloves and safety goggles when working with liquid refrigerant) |
| R-1234yf at 14.7psia will boil at about: | correct answer: -20 degrees F (14.7psia = 0psig, use P/T chart to find pressure closest to 0psig, then find corresponding temperature in side column) incorrect options: 0 degrees F, 20 degrees F, 40 degrees F |
| When there is excessive moisture collecting in purge unit of low pressure refrigeration system, this indicates that: | correct answer: condenser or chiller barrel tubes are leaking incorrect options: system was charged with contaminated refrigerant, purge unit is not operating properly, purge unit needs adjustment |
| ASHRAE Standard 15-1994 requires equipment room refrigerant sensors for what safety group classification? | correct answer: all refrigerant safety groups incorrect options: A-1, A-2, B-2 |
| After reaching required recovery vacuum on chiller, you should: | correct: wait for at least few minutes to see if system pressure rises, indicating there is still refrig. in liquid form or in oil incorrect: immediately disconnect recovery equipment, break vacuum with N2, pressurize system with N2/perform leak check |
| When charging chiller, refrigerant vapor is introduced into system before charging with liquid. This is because: | correct: liquid charged into deep vacuum will cause refrig. to boil/may lower temp. enough to freeze water in tubes incorrect: it increases pressure slowly preventing failure of rupture disc, it is faster, liquid charging is more difficult to control |
| When evacuating system, use of too large vacuum pump can cause: | correct answer: trapped water to freeze incorrect options: trapped oil to freeze, trapped refrigerant to freeze, valves to freeze |
| On low pressure chiller with open-type compressor, what is very susceptible to leaks? | correct answer: shaft seal incorrect options: chiller tubes, charging connections, shaft bearings |
| What steps may be taken to prevent air accumulation into idle low pressure refrigeration system? | correct answer: system pressure should be maintained slightly above atmospheric pressure incorrect options: leave purge unit online at all times, open air vents on condenser, intermittently operate system with no load |
| Commercial and industrial process refrigeration systems must be repaired when leak rate exceeds ____ of charge per year? | correct answer: 30% incorrect options: 5%, 10%, 20% |
| When recovering vapor from low pressure refrigeration system: | correct: system water pumps/recovery compressor/recovery condenser water should all be on incorrect: water pumps on and recovery comp. off, system water pumps/recovery comp. on and recovery cond. water off, system water pumps off and recovery comp. on |
| Purge unit takes its suction from: | correct answer: top of condenser incorrect options: compressor oil sump, top of evaporator, suction elbow |
| Which of following repairs would always be considered "major" under EPA's regulations? | correct answer: replacement of evaporator coil incorrect options: replacement of filter drier, replacement of switch, replacement of purge unit |
| Charging refrigerant liquid into refrigeration system when it is under 29 inch Hg vacuum can cause: | correct answer: system water to freeze incorrect options: liquid to absorb excess moisture, purge unit to operate, refrigerant liquid to freeze |
| According to EPA, there is approximately how much refrigerant vapor left in average 350 ton, R-123 chiller at 0psig pressure once all R-123 liquid has been removed? | correct answer: 100 lbs. incorrect options: none, 10 lbs., 20 lbs. |
| Oil sample should be taken when: | correct answer: there has been compressor burnout incorrect options: new filter drier has been installed, unit is not cooling properly, recycled refrigerant has been added to unit |
| Low pressure refrigerant chillers require purge units because: | correct answer: system operates below atmospheric pressure incorrect options: purge units remove moisture, purge units remove refrigerant from oil sump, purge units remove CFCs from chiller |
| Refrigerant recovery typically starts with what because it is faster? | correct answer: liquid recovery incorrect options: vapor recovery, combined vapor and liquid recovery, oil separation |
| Under EPA regulations, what is used to pressurize low pressure chiller for purpose of opening system for non-major repair? | correct answer: warming refrigerant incorrect options: adding nitrogen, adding compressed air, adding carbon dioxide |
| Primary water source for recovery unit (water-cooled) condensing coil is: | correct answer: local municipal water supply incorrect options: chilled water, condenser water, deionized water |
| System does not have to be evacuated to required level when: | correct answer: leaks in appliance make evacuation to prescribed level unattainable incorrect options: repair is major, repair is followed by evacuation of appliance to environment, appliance is being disposed |
| Which action listed below is proper method to reduce refrigerant loss from purge unit on low pressure chiller? | correct answer: leak test and repair chiller incorrect options: seal purge unit discharge, pipe purge unit back into low side, pipe purge unit into recovery unit |
| Identify pressure corresponding to 32 degrees F for R-123: | correct answer: 20 inches Hg vacuum (rounded between 19.5 and 20.7 inches Hg vacuum or -19.5 and -20.7 on P/T chart for nearest saturation temperatures of 30 and 35 degrees F) incorrect options: 23" Hg vacuum, 17" Hg vacuum, 11" Hg vacuum |
| What precaution should be taken prior to recovering refrigerant from chiller suspected of having tube leaks? | correct answer: drain water sides of evaporator and condenser incorrect options: run circulating pumps, be certain purge unit is operating, open condenser vents |
| Pressure relief valves must never be: | correct answer: installed in series incorrect options: installed in parallel, installed vertically, installed horizontally |
| If you are going to be removing oil from low pressure system, you should heat oil because: | correct answer: less refrigerant will be contained in oil at higher temperature incorrect options: can warm hands on container, warmer oil has lower viscosity and flows more easily, shows heater is working |
| After recovering liquid refrigerant, you must: | correct answer: recover vapor refrigerant incorrect options: pressurize system with nitrogen, remove oil from system, solvent flush entire system |
| EPA regulations require that any appliances containing more than 50 pounds of refrigerant (except for commercial and industrial process refrigeration) must be repaired when leak rate exceeds what percentage of charge per year? | correct answer: 10% incorrect options: 5%, 20%, 30% |
| On low pressure chillers, moisture typically enters refrigerant system through: | correct answer: air leaks from areas with gaskets or fittings incorrect options: air leaks in rupture disc assembly, tube leaks, air leaks from charging valve |
| R-123 at pressure of 18 inches Hg vacuum has saturation temperature of: | correct answer: 40 degrees F (rounded from 18.1 inches Hg vacuum or -18.1 on P/T chart then find corresponding saturation temperature in side column) incorrect options: -20 degrees F, 0 degrees F, 20 degrees F |
| Lowest access point on low pressure centrifugal air conditioning unit is: | correct answer: evaporator charging valve incorrect options: condenser service valve, compressor cooler jacket, purge unit exhaust port |
| According to ASHRAE Guideline 3-1996, if pressure in low pressure system rises from 1mm Hg to level above what during standing vacuum test, system should be checked for leaks? | correct answer: 2.5mm Hg incorrect options: 1.5mm Hg, 2.0mm Hg, 3.0mm Hg |
| During chiller evacuation, water is circulated to: | correct answer: prevent freezing of water incorrect options: speed up recovery process, prevent loss of refrigerant to atmosphere, maintain constant refrigerant pressure |
| When charging R-410A water chiller, you must first charge with vapor to pressure of at least what before switching to liquid charging? | correct answer: 120psig (rounded from 118psig as corresponding pressure to closest temperature to 36 degrees F on P/T chart for R-410A) incorrect options: 20psig, 220psig, 320psig |
| If you leak test low pressure chiller with nitrogen in excess of 10psig, you could cause what to fail? | correct answer: rupture disc incorrect options: condenser tubes, purge unit shells, evaporator tubes |
| ASHRAE Standard 15-1994 requires that each machinery room must activate alarm and mechanical ventilation before refrigerant concentrations exceed: | correct answer: TLV-TWA (threshold limit value - time weighted average) incorrect options: EEL (emergency exposure limit), UTL (upper threshold limit), COP (coefficient of performance) |
| Which repair would not fall under EPA definition of "major maintenance, service, or repair?" | correct answer: replacing oil filter incorrect options: replacing compressor, retubing condenser, replacing fin and tube forced air evaporator coil |
| Refrigerant is added to centrifugal machine through: | correct answer: evaporator charging valve incorrect options: float valve, compressor service valve, condenser charging valve |
| If you are using recovery machine manufactured after November 15, 1993, you must evacuate any low pressure appliance to what level before making major repair? | correct answer: 25mm Hg absolute incorrect options: 0psig, 15 inches Hg vacuum, 25 inches Hg vacuum |
| If you suspect leak in water box of chiller, you should place leak detector probe where and sniff for refrigerants? | correct answer: through drain valve incorrect options: at rupture disc, through vent valve, through test plug |
| To determine how much vapor to charge into evacuated chiller, you should charge with vapor until: | correct answer: system pressure corresponds to refrigerant saturation temperature of 36 degrees F incorrect options: recovery unit liquid level drops, have charged with vapor for 15 minutes, recovery unit pressure drops |
| Centrifugal chiller's rupture disc is connected to chiller's: | correct answer: evaporator incorrect options: condenser, liquid line, economizer |
| To remove ice from sight or viewing glasses, use: | correct answer: alcohol spray incorrect options: R-11, water, screwdriver or flat file |
| According to ASHRAE Standard 34, what is safety classification of R-123? | correct answer: B-1 (found on top of P/T chart) incorrect options: A-1, A-2, B-2 |
| Typical design burst pressure for rupture disc on low pressure centrifugal air conditioning system is set at: | correct answer: 15psig incorrect options: 7psig, 10psig, 28psig |
| During evacuation of system containing large amounts of moisture, you can prevent freezing of this moisture by increasing pressure with what gas? | correct answer: nitrogen incorrect options: R-22, air, oxygen |
| After system servicing and recharging, why is refrigerant vapor reintroduced to chiller before refrigerant liquid? | correct answer: liquid charged into deep vacuum will evaporate and may lower temperature freezing water in heat exchanger tube bundle incorrect options: |
| Which of following safety precautions should be adhered to for low pressure systems? | correct answer: use gloves and safety goggles when working with liquid refrigerant incorrect options: |
| Most low pressure appliances fall under what leak rate category? | correct answer: comfort cooling incorrect options: commercial refrigeration, industrial process refrigeration, ice making refrigeration |
| Which of following is not required for system mothballing? | correct answer: removing appliance and storing it in warehouse at facility incorrect options: |
| How long are equipment owner/operators responsible for keeping records of all leak inspections, initial verification, and any completed leak repair follow-up verification tests? | correct answer: 3 years incorrect options: 1 year, 2 years, 5 years |
| Increasing pressure with pressure with nitrogen during dehydration does what? | correct answer: both prevents moisture from freezing and increases speed of dehydration incorrect options: |
| 14.7psia equals: | correct answer: 0psig incorrect options: 15psig, 30psig, 50psig |
| R-134a chiller should be initially charged with vapor to pressure of at least what before switching to liquid charging? | correct answer: 30psig (rounded from 30.4psig as corresponding pressure to closest temperature to 36 degrees F on P/T chart for R-134a) incorrect options: |
| ASHRAE Standard 15 does not require equipment room refrigerant detector for what refrigerant as long as mechanical ventilation system in machinery room is run continuously? | correct answer: R-717 (ammonia) incorrect options: R-12, R-134a, R-410A |
| Low pressure system should be checked for leaks if system pressure rises between what levels during standard vacuum test according to ASHRAE Guideline 3? | correct answer: 1mm Hg to above 2.5mm Hg incorrect options: |
| When must leak rate of appliance using regulated refrigerant be calculated? | correct answer: when topping off or recharging system incorrect options: due to loss of charge |
| What reason cannot be used to extend appliance leak repair deadline? | correct answer: not having certified service technician available for service incorrect options: |
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