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Question 1F-gas certification of refrigeration technicians (category I)

Under F-gas regulations, which property of the refrigerant is the primary reason a technician must hold a Category I certificate for large systems?

  1. Its global warming potential expressed in CO2 equivalents
  2. Its ability to dissolve in compressor lubricating oil
  3. Its classification as a fluorinated greenhouse gas above the threshold charge Correct answer.
  4. Its low boiling point at atmospheric pressure

Explanation

Category I certification is required because the refrigerant is a fluorinated greenhouse gas and the charge exceeds the thresholds set by regulation. The certificate demonstrates competence to handle equipment with larger charges of these controlled substances. Other physical properties such as boiling point or oil solubility are not the legal basis for certification categories.

Question 2F-gas certification of refrigeration technicians (category I)

A technician recovers refrigerant from a commercial refrigeration system. What is the correct procedure before the recovered refrigerant is charged back into the same or another system?

  1. Reuse it directly if the recovery cylinder pressure looks normal
  2. Filter and dry it, then verify purity against specification Correct answer.
  3. Vent the residual non-condensables to atmosphere
  4. Mix it with virgin refrigerant to dilute impurities

Explanation

Recovered refrigerant must be processed so that moisture, acid and particulates are removed, and its composition must be verified before reuse. Only then can it be safely charged back into equipment. Direct reuse, venting or blending with virgin gas does not guarantee the required purity and can damage the system.

Question 3F-gas certification of refrigeration technicians (category I)

Which statement correctly describes the leak-checking obligation for an operator of a system containing a fluorinated greenhouse gas?

  1. Leak checks are only needed after a leak has been reported by users
  2. A single check at commissioning is sufficient for the plant lifetime
  3. Checks apply only to systems charged with more than 100 tonnes of CO2 equivalent
  4. Checks are required at intervals that depend on the CO2-equivalent charge Correct answer.

Explanation

The regulation sets leak-check frequencies according to the size of the charge expressed in tonnes of CO2 equivalent. Larger charges require more frequent checks, and leak detection systems can extend the intervals. A one-off check or a purely reactive approach does not satisfy the obligation.

Question 4F-gas certification of refrigeration technicians (category I)

What is the main purpose of a pressure test with dry nitrogen before charging a new refrigeration system?

  1. To remove moisture from the refrigerant circuit
  2. To measure the exact refrigerant charge mass
  3. To confirm the system can hold pressure and has no leaks Correct answer.
  4. To calibrate the high-pressure switch set point

Explanation

A dry nitrogen pressure test verifies the mechanical tightness of the circuit before any refrigerant is introduced. It protects both the environment and the product by finding leaks early. Moisture removal, switch calibration and charge measurement are separate procedures.

Question 5F-gas certification of refrigeration technicians (category I)

Why must a system be evacuated to a deep vacuum before charging with refrigerant?

  1. To test the strength of the pipework
  2. To cool the compressor before start-up
  3. To increase the refrigerant charge capacity
  4. To remove air and moisture from the circuit Correct answer.

Explanation

Evacuation removes non-condensable gases and water vapour that would otherwise cause high discharge pressures, acid formation and ice blockage at the expansion device. A deep vacuum and a standing vacuum test confirm that the circuit is dry and tight. Strength testing and cooling are unrelated purposes.

Question 6F-gas certification of refrigeration technicians (category I)

A technician must dispose of a recovered refrigerant that is contaminated beyond reuse. What is the acceptable route?

  1. Send it to a licensed destruction or reclamation facility Correct answer.
  2. Burn it in the workshop heater
  3. Release it slowly outdoors in small quantities
  4. Store it indefinitely in an unlabelled cylinder

Explanation

Refrigerant that cannot be reclaimed must be handed to a licensed operator for destruction or proper reclamation. This keeps the controlled substance within a documented chain of custody. Release, uncontrolled burning and indefinite storage are all non-compliant.

Question 7F-gas certification of refrigeration technicians (category I)

Which personal protective equipment is essential when transferring refrigerant from a system into a recovery cylinder?

  1. Only a high-visibility vest
  2. Ear defenders only
  3. Safety glasses, gloves and face protection Correct answer.
  4. A dust mask only

Explanation

Liquid refrigerant and cold vapour can cause severe frostbite to skin and eyes, so eye and face protection plus suitable gloves are required. A high-visibility vest, hearing protection or a simple dust mask does not protect against cold burns or pressure release.

Question 8F-gas certification of refrigeration technicians (category I)

What information must a technician record after recovering refrigerant from a system?

  1. Only the colour of the recovery cylinder
  2. The ambient temperature at the time of work
  3. The quantity recovered and the equipment it came from Correct answer.
  4. The name of the refrigerant supplier

Explanation

Records must show the quantity of refrigerant recovered and the equipment concerned so that the movement of controlled substances can be traced. These records support reporting obligations and internal audits. Colour, ambient temperature and supplier names are not the required data.

Question 9F-gas certification of refrigeration technicians (category I)

A system uses a refrigerant with a high global warming potential and a charge of several hundred kilograms. Why is preventing leaks economically as well as environmentally important?

  1. Leaked refrigerant must be replaced, and the gas has a high purchase cost and tax burden Correct answer.
  2. Leaks reduce the compressor oil level automatically
  3. Leaked refrigerant acts as a lubricant for the expansion valve
  4. Leaks improve system efficiency by lowering head pressure

Explanation

Refrigerant lost through leaks must be topped up, and high-GWP gases carry significant cost and often taxation. Leak prevention therefore protects both the environment and operating budget. Leaks do not improve efficiency or lubricate components, and oil level is a separate concern.

Question 10F-gas certification of refrigeration technicians (category I)

During a standing vacuum test, the pressure rises slowly after the pump is isolated. What is the most likely interpretation?

  1. There is moisture in the circuit or a small leak Correct answer.
  2. The vacuum pump is too powerful
  3. The circuit is perfectly dry and tight
  4. The gauge manifold has been calibrated

Explanation

A slow pressure rise during a standing vacuum test indicates either residual moisture evaporating or a small leak allowing air in. The circuit should be further investigated before charging. A tight, dry system holds its vacuum, and pump power or gauge calibration does not explain the rise.

Question 11F-gas certification of refrigeration technicians (category I)

A technician suspects non-condensable gases in a system. Which observation best supports this diagnosis?

  1. The compressor current is lower than the nameplate value
  2. Suction pressure is lower than normal and superheat is high
  3. Discharge pressure and discharge temperature are higher than normal for the conditions Correct answer.
  4. The evaporator frosts evenly across its surface

Explanation

Non-condensable gases accumulate in the condenser and raise the condensing pressure and discharge temperature above what the ambient conditions would predict. Low suction pressure with high superheat points to undercharge, and low current suggests reduced load. Even frost distribution is a sign of correct operation.

Question 12F-gas certification of refrigeration technicians (category I)

Which practice best minimises refrigerant emissions when replacing a filter drier on a small system?

  1. Loosen a flare joint and vent slowly while working
  2. Recover the refrigerant, then open the circuit and work promptly Correct answer.
  3. Warm the drier with a torch to drive gas out
  4. Cut the lines and let the charge escape quickly

Explanation

The refrigerant must be recovered before the circuit is opened, and the work should be done quickly to limit the small residual release. Cutting lines, deliberate venting and heating the drier all release refrigerant unnecessarily. Good practice keeps emissions as low as practicable.

Question 13F-gas certification of refrigeration technicians (category I)

A recovery cylinder is filled to 80 percent of its capacity by weight. Why is this limit applied?

  1. To keep the cylinder light enough for one person to lift
  2. To allow the cylinder to be used for two different refrigerants
  3. To leave room for liquid expansion and prevent hydraulic pressure rise Correct answer.
  4. To reduce the cost of the recovery process

Explanation

Recovery cylinders must never be filled completely because liquid refrigerant expands with temperature and can create dangerous hydraulic pressure. The 80 percent limit provides a safety margin. Weight limits, refrigerant mixing and cost are not the reason for the rule.

Question 14F-gas certification of refrigeration technicians (category I)

Which action is required before a technician may work on a system that uses a flammable refrigerant?

  1. Increase the charge to improve cooling performance
  2. Disable all ventilation to keep the refrigerant concentrated
  3. Seal the room to prevent refrigerant escape to other areas
  4. Ensure ignition sources are removed and the area is ventilated Correct answer.

Explanation

Flammable refrigerants require removal of ignition sources and adequate ventilation to keep any release below dangerous concentrations. Sealing the room or disabling ventilation would increase risk. Increasing the charge is never a safety measure.

Question 15F-gas certification of refrigeration technicians (category I)

When brazing pipework on a system containing refrigerant, what precaution protects both the technician and the circuit?

  1. Leave the system pressurised during brazing
  2. Use compressed air to cool the joint
  3. Purge the pipe with oxygen before brazing
  4. Flow dry nitrogen through the pipe while brazing Correct answer.

Explanation

A dry nitrogen purge prevents oxidation inside the pipe and displaces flammable or harmful gases, protecting the circuit and the technician. Oxygen or compressed air can create explosive mixtures or heavy oxidation. The system must not remain pressurised during brazing.

Question 16F-gas certification of refrigeration technicians (category I)

A leak is found at a flare connection on a system using a high-GWP refrigerant. Which repair approach is most appropriate?

  1. Apply sealant tape over the joint and refill
  2. Increase the charge to compensate for the leak
  3. Recover the charge, remake the joint correctly, then pressure test and evacuate Correct answer.
  4. Tighten the flare and add refrigerant without further action

Explanation

The correct repair is to recover the refrigerant, remake the joint to specification, then pressure test and evacuate before recharging. This addresses the root cause and verifies tightness. Tightening without testing, external sealant or simply adding gas leaves the leak unresolved.

Question 17F-gas certification of refrigeration technicians (category I)

Which set of records best supports compliance for a system containing a fluorinated greenhouse gas?

  1. Charge quantity, leak checks performed, repairs and refrigerant added or recovered Correct answer.
  2. Operator training certificates only
  3. Purchase receipts for the original refrigerant only
  4. Manufacturer brochures for the installed equipment

Explanation

Compliance records must document the charge, the leak checks carried out, any repairs and all refrigerant added or recovered. This provides a traceable history of the controlled substance. Receipts, training certificates or brochures alone do not capture operational movements.

Question 18F-gas certification of refrigeration technicians (category I)

A technician is about to recover refrigerant from a system that has been running with a suspected compressor burnout. What additional precaution is important?

  1. Recover only the liquid portion and vent the vapour
  2. Use recovery equipment suited to acidic contaminated refrigerant and check the oil Correct answer.
  3. Use standard recovery equipment without any change
  4. Vent the first part of the charge to clear the lines

Explanation

Burnout produces acidic contamination that can damage recovery equipment and harm the technician, so appropriate equipment and oil checks are needed. Venting any portion of the charge is prohibited. The entire charge must be recovered and the contamination assessed.

Question 19F-gas certification of refrigeration technicians (category I)

Why is it important to identify the exact refrigerant type before recovering it into a cylinder?

  1. To select the correct cylinder and avoid mixing incompatible refrigerants Correct answer.
  2. To determine the ambient humidity
  3. To calculate the compressor oil viscosity
  4. To decide the colour of the manifold gauges

Explanation

Each refrigerant must be recovered into a dedicated cylinder because mixing different refrigerants creates an undefined blend that cannot be reclaimed or reused. Identification also ensures the correct pressure rating and handling. Gauge colour, humidity and oil viscosity are not the reason.

Question 20F-gas certification of refrigeration technicians (category I)

A system with a CO2-equivalent charge above the threshold for mandatory leak detection has no automatic detection system installed. What is the consequence?

  1. The system may be operated without any leak checks
  2. Leak checks must be carried out at the shorter interval required without a detection system Correct answer.
  3. No consequence, because detection systems are optional
  4. The refrigerant may be vented instead of checked

Explanation

Where an automatic leak detection system is absent, the regulation requires more frequent manual leak checks. Installing a detection system can extend the interval, but it is not a way to avoid checks altogether. Venting is never permitted.

Question 21F-gas certification of refrigeration technicians (category I)

Which combination of readings most strongly suggests that a system is undercharged?

  1. High discharge pressure with normal subcooling
  2. Low suction pressure, high superheat and bubbles in the liquid line sight glass Correct answer.
  3. Equal suction and discharge pressures at standstill
  4. High suction pressure and low superheat

Explanation

Undercharge typically shows low suction pressure, high superheat and bubbles in the sight glass as liquid flashes early. High suction with low superheat suggests overcharge, and equal pressures at standstill are normal. High discharge pressure with normal subcooling does not indicate undercharge.

Question 22F-gas certification of refrigeration technicians (category I)

A technician plans to retrofit a system from a high-GWP refrigerant to a lower-GWP alternative. Which consideration is most critical before proceeding?

  1. Choosing the refrigerant with the lowest number on the safety data sheet
  2. Confirming the new refrigerant is cheaper per kilogram
  3. Matching the new refrigerant to the lubricant, materials and components of the existing system Correct answer.
  4. Ensuring the new refrigerant has the same cylinder colour

Explanation

A retrofit requires checking compatibility of the new refrigerant with the lubricant, elastomers, seals and system components, and often adjusting controls. Cost, cylinder colour or document numbering do not determine technical suitability. An incompatible choice can cause failure or unsafe operation.

Question 23F-gas certification of refrigeration technicians (category I)

During recovery, the recovery cylinder becomes cold and the recovery rate slows markedly. What is the most appropriate action?

  1. Increase the recovery machine speed beyond its rating
  2. Use a cylinder heater or throttle the recovery to allow controlled warming Correct answer.
  3. Open the system to atmosphere to equalise pressure
  4. Disconnect the cylinder and vent the remaining charge

Explanation

As liquid evaporates in the cylinder, the cylinder cools and the pressure differential falls, slowing recovery. Controlled warming of the cylinder or throttling the process restores the rate safely. Exceeding equipment ratings, opening to atmosphere or venting are unsafe or prohibited.

Question 24F-gas certification of refrigeration technicians (category I)

A leak detection system alarms repeatedly on a system that passes a manual leak test. Which explanation is most plausible?

  1. The refrigerant has zero global warming potential
  2. The detector is poorly positioned, fouled or calibrated incorrectly Correct answer.
  3. The system charge is far below the design value
  4. The compressor is running at full load

Explanation

Repeated alarms without a confirmed leak suggest the detection system itself is at fault, for example through poor placement, contamination or calibration drift. A manual test that passes does not prove the detector is working correctly. GWP, charge level or compressor load do not explain a false alarm.

Question 25F-gas certification of refrigeration technicians (category I)

A technician must decide whether recovered refrigerant from a large system can be returned to the owner for reuse. Which factor is decisive?

  1. The ambient temperature during recovery
  2. The colour of the recovery cylinder
  3. Analytical verification that the refrigerant meets the required purity specification Correct answer.
  4. The brand of the recovery machine

Explanation

Reuse is only acceptable when analysis confirms the refrigerant meets the purity specification for the intended application. Cylinder colour, ambient conditions and equipment brand do not establish purity. Without verification, the refrigerant should be reclaimed or destroyed.

Question 26F-gas certification of refrigeration technicians (category I)

Under the F-gas rules for stationary refrigeration, what does the 'charge' of a system refer to?

  1. The volume of lubricating oil circulating with the refrigerant
  2. The maximum pressure the high-pressure switch allows
  3. The total mass of refrigerant contained in the system's circuit Correct answer.
  4. The electrical current drawn by the compressor at full load

Explanation

Charge means the quantity of refrigerant held within the system, normally expressed in kilograms. It is the figure used to compare against leak-check and certification thresholds. Pressure limits and oil volumes are separate design values and are not the charge.

Question 27F-gas certification of refrigeration technicians (category I)

Which property makes a refrigerant suitable for classifying a technician's certification category under F-gas rules?

  1. Whether it boils below zero degrees Celsius at atmospheric pressure
  2. Whether it is miscible with mineral oil
  3. Whether it is heavier than air at room temperature
  4. Whether it is a fluorinated greenhouse gas controlled by the regulation Correct answer.

Explanation

The certification framework applies to equipment containing fluorinated greenhouse gases, so the chemical family of the refrigerant determines whether the rules apply. Boiling point, density and oil miscibility are technical selection criteria, not regulatory ones. A refrigerant such as ammonia falls outside the F-gas scope.

Question 28F-gas certification of refrigeration technicians (category I)

What is the main purpose of a periodic leak check on a system containing a fluorinated greenhouse gas?

  1. To confirm that the compressor delivers its rated capacity
  2. To find and repair leaks so that emissions are limited Correct answer.
  3. To verify the accuracy of the room thermostat
  4. To measure the power factor of the installation

Explanation

Leak checking exists to detect losses of controlled refrigerant early so they can be repaired before large quantities escape. It is an emissions-control obligation, not a performance test. Capacity, thermostat accuracy and electrical measurements belong to maintenance and commissioning.

Question 29F-gas certification of refrigeration technicians (category I)

Which instrument is specifically intended for detecting leaks of halogenated refrigerants in a plant room?

  1. A clamp meter
  2. A manometer filled with water
  3. An electronic refrigerant leak detector Correct answer.
  4. A sling psychrometer

Explanation

Electronic leak detectors are designed to respond to halogenated refrigerant vapour and are the standard tool for locating leaks. A psychrometer measures humidity, a clamp meter measures current, and a water manometer measures low pressure. None of those respond to refrigerant concentration.

Question 30F-gas certification of refrigeration technicians (category I)

Why must a refrigerant cylinder never be filled completely with liquid?

  1. Liquid expansion with rising temperature could hydraulically overpressure the cylinder Correct answer.
  2. The cylinder valve would seize closed under full liquid contact
  3. The refrigerant would decompose if it touched the whole inner surface
  4. Recovery pumps cannot move liquid refrigerant at all

Explanation

A cylinder filled entirely with liquid has no vapour space to absorb thermal expansion, so warming can raise the internal pressure until the shell fails. A defined ullage or filling ratio by weight leaves that safety margin. Refrigerant does not decompose merely from contact with the cylinder wall, and recovery pumps handle liquid routinely.

Question 31F-gas certification of refrigeration technicians (category I)

What does the global warming potential of a refrigerant express?

  1. Its ability to carry heat per kilogram compared with water
  2. Its tendency to form acid when mixed with moisture
  3. Its climate impact relative to carbon dioxide over a defined time horizon Correct answer.
  4. Its toxicity relative to carbon dioxide at the same concentration

Explanation

GWP is a ratio comparing the radiative forcing of a substance with that of carbon dioxide over a stated period, commonly 100 years. Multiplying charge by GWP gives the CO2-equivalent tonnage used in reporting. Toxicity, heat capacity and acid formation are unrelated properties.

Question 32F-gas certification of refrigeration technicians (category I)

A technician holds a category I certificate. Which work does this typically authorise?

  1. All refrigerant-handling activities covered by the regulation, including large charges Correct answer.
  2. Only the recovery of refrigerant from mobile air-conditioning units
  3. Only leak checking, with no recovery or charging permitted
  4. Only work on hermetically sealed domestic refrigerators

Explanation

Category I is the broadest qualification and covers the full range of handling tasks, including systems with large charges. Lower categories are restricted by charge size or equipment type. A category I holder is therefore not limited to sealed domestic units or to leak checking alone.

Question 33F-gas certification of refrigeration technicians (category I)

What is the purpose of a pressure-relief device fitted to a liquid receiver?

  1. To vent refrigerant safely if internal pressure exceeds a set limit Correct answer.
  2. To indicate the liquid level inside the vessel
  3. To maintain a constant evaporating pressure in the cooler
  4. To prevent liquid refrigerant from leaving the receiver

Explanation

A relief device protects the vessel from overpressure by opening at a predetermined setting, for example when a receiver is isolated and warms up. Evaporating pressure is controlled by the expansion device and compressor. Liquid level is shown by a sight glass or gauge, not by the relief valve.

Question 34F-gas certification of refrigeration technicians (category I)

A system with a large CO2-equivalent charge has no automatic leak detection and the operator wants to delay it. What is the correct position under F-gas rules?

  1. Detection can be replaced by fitting extra pressure gauges
  2. Automatic detection is mandatory once the CO2-equivalent threshold is exceeded, so installation cannot be deferred Correct answer.
  3. Detection is only needed if the refrigerant is flammable
  4. Detection is optional provided a manual check is done twice as often

Explanation

Where the CO2-equivalent charge of a system passes the defined threshold, an automatic leak detection system must be installed, and the obligation is not traded against more frequent manual checks. Manual checking is an additional duty, not a substitute. Flammability is a separate safety matter, and gauges do not detect leaks.

Question 35F-gas certification of refrigeration technicians (category I)

A leak is repaired on a system above the leak-check threshold. What does good practice require afterwards?

  1. Removal of the leak detection system as no longer needed
  2. Permanent shutdown of the plant until the next scheduled audit
  3. A follow-up leak check within a defined short period to confirm the repair Correct answer.
  4. Immediate replacement of the whole refrigerant charge

Explanation

After a significant leak has been repaired, the repair must be verified by a leak check carried out within a set period, typically one month, to prove the fix holds. Replacing the whole charge or shutting the plant down is not implied. The detection system remains required while the charge stays above the threshold.

Question 36F-gas certification of refrigeration technicians (category I)

A technician must add refrigerant to a system and wants to determine the correct amount. Which information is most reliable?

  1. The manufacturer's specified charge and the measured quantity added by weight Correct answer.
  2. The sound the expansion valve makes during operation
  3. The pressure shown on the low-side gauge alone
  4. The temperature of the suction line felt by hand

Explanation

The correct charge is the manufacturer's stated value, and it should be confirmed by weighing the refrigerant added with a charging scale. Gauge pressure alone varies with ambient and load, so it cannot give a quantity. Touch and sound are qualitative indicators only.

Question 37F-gas certification of refrigeration technicians (category I)

Which document must accompany a refrigerant cylinder when it is transported between sites?

  1. The system's commissioning certificate
  2. The safety data sheet for the refrigerant concerned Correct answer.
  3. The building's energy performance certificate
  4. The compressor maintenance log

Explanation

The safety data sheet gives the hazard information needed by anyone handling or receiving the cylinder during transport and storage. Commissioning certificates and maintenance logs relate to the installed plant, not to the cylinder contents. An energy certificate has no bearing on refrigerant transport.

Question 38F-gas certification of refrigeration technicians (category I)

A technician recovers refrigerant into a cylinder and then needs to move it. Which precaution is most important for the cylinder during transport?

  1. Lay it on its side to lower its centre of gravity
  2. Remove the valve cap to allow venting
  3. Secure it upright with the valve capped so it cannot roll or be struck Correct answer.
  4. Warm it slightly to reduce the pressure inside

Explanation

Cylinders should travel upright, restrained against movement, with valve caps fitted to protect the valve from impact. Laying a cylinder down risks liquid reaching the valve and makes it harder to secure. Warming a cylinder raises pressure, and venting the valve releases refrigerant illegally.

Question 39F-gas certification of refrigeration technicians (category I)

A technician is unsure whether a reclaimed refrigerant meets the purity needed for reuse in another owner's equipment. What is the correct approach?

  1. Return it to the system it came from without any check
  2. Have it analysed against the relevant specification before it is declared reusable Correct answer.
  3. Assume it is pure if it was recovered from a working system
  4. Blend it with new refrigerant to dilute any impurities

Explanation

Reclaimed refrigerant may only be reused when it has been tested and shown to meet the applicable purity standard. Recovering from a functioning system does not guarantee purity. Blending with virgin product is not an acceptable substitute for analysis, and unverified reuse risks damaging equipment.

Question 40F-gas certification of refrigeration technicians (category I)

Why should a recovery cylinder be weighed before and after a recovery job?

  1. To check whether the cylinder valve is the correct thread
  2. To calculate the electrical energy used by the recovery machine
  3. To determine the mass recovered and keep within the safe filling limit Correct answer.
  4. To measure the moisture content of the recovered refrigerant

Explanation

Weighing gives the quantity transferred and shows how much of the permitted fill has been used, which protects against overfilling. It says nothing about energy consumption, valve thread type or moisture. Moisture is assessed by analysis, not by mass.

Question 41F-gas certification of refrigeration technicians (category I)

A technician finds that a system's sight glass shows bubbles continuously even though the charge is correct by weight. What is the most reasonable interpretation?

  1. The system is definitely undercharged and must be topped up
  2. The compressor is running backwards
  3. The refrigerant has completely changed composition
  4. The bubbles may be due to other causes such as flash gas from pressure drop, so further checks are needed Correct answer.

Explanation

Bubbles in a sight glass are not proof of undercharge because a pressure drop across a restriction or subcooling behaviour can also produce flash gas. Since the charge already matches the manufacturer's figure, adding more would overcharge the system. Other operating data should be reviewed before concluding anything.

Question 42F-gas certification of refrigeration technicians (category I)

Which action best protects the environment when a system is permanently decommissioned?

  1. Run the compressor until the low-pressure switch trips and then cut the pipes
  2. Drain the oil to the drain and leave the refrigerant in the circuit
  3. Open the circuit first and let the charge escape slowly
  4. Recover the entire refrigerant charge before dismantling any part of the circuit Correct answer.

Explanation

The whole charge must be recovered before the circuit is opened so that no refrigerant is vented to atmosphere. Letting it escape, even slowly, is a release and is not permitted. Cutting pipework or leaving the charge in place during scrapping would also result in emissions.

Question 43F-gas certification of refrigeration technicians (category I)

A technician is checking a system's records and finds the CO2-equivalent figure. How is it obtained?

  1. Multiply the refrigerant charge in kilograms by the refrigerant's GWP Correct answer.
  2. Divide the system volume by the refrigerant's molecular mass
  3. Add the suction and discharge pressures in bar
  4. Multiply the compressor power by its running hours

Explanation

The CO2-equivalent of a charge is the mass of refrigerant multiplied by its global warming potential, giving a value in tonnes of CO2 equivalent. Volume, molecular mass, pressures and energy consumption are not part of this calculation. The result is what determines leak-check frequency and detection duties.

Question 44F-gas certification of refrigeration technicians (category I)

Why is it important that recovered refrigerant is never mixed with a different refrigerant type in the same cylinder?

  1. The cylinder metal reacts chemically with mixtures
  2. Mixed refrigerant always becomes flammable
  3. Mixed refrigerant cannot be reclaimed to specification and may become unrecoverable waste Correct answer.
  4. The recovery machine will overheat immediately

Explanation

Reclaimers can only restore a single identified refrigerant to specification, so a mixture has no route back to virgin quality and often must be destroyed. The cylinder material does not react with mixtures, and flammability is a property of the substances involved, not of mixing as such. Recovery machines do not fail simply because a mixture is drawn in.

Question 45F-gas certification of refrigeration technicians (category I)

A large system must be checked for leaks at the frequency set by its CO2-equivalent charge. Which record best demonstrates that this duty has been met?

  1. Dated leak-check records signed by a certified technician, showing findings and any repairs Correct answer.
  2. The original purchase invoice for the refrigeration plant
  3. The compressor manufacturer's spare-parts list
  4. The building's fire inspection certificate

Explanation

Compliance is shown by dated records of each leak check, made by a certified person, with the results and any remedial work noted. Invoices, parts lists and fire certificates do not evidence refrigerant containment checks. The records must be retained and made available on request.

Question 46F-gas certification of refrigeration technicians (category I)

A technician needs to recover refrigerant from a system that will later be charged with a different, lower-GWP refrigerant. What is the most important step before the old charge is removed?

  1. Recover the old charge into the cylinder already holding the new refrigerant
  2. Leave a small residual charge to lubricate the circuit during the change
  3. Confirm the identity of the existing refrigerant and recover it into a dedicated, correctly labelled cylinder Correct answer.
  4. Flush the circuit with the new refrigerant and vent the mixture

Explanation

The existing refrigerant must be identified so it can be recovered into its own labelled cylinder and handled correctly; cross-contamination would make both charges unusable. Venting a flush mixture or mixing old and new refrigerants in one cylinder destroys recoverability. Residual charge must not be left in the circuit.

Question 47F-gas certification of refrigeration technicians (category I)

A technician finds that a system's leak rate has been calculated as unusually high over a year. Which conclusion is most consistent with the rules?

  1. The system has a significant leak and must be repaired promptly, with the repair verified afterwards Correct answer.
  2. The system should simply be topped up and the matter closed
  3. The leak rate figure only matters for systems using flammable refrigerants
  4. The system may continue indefinitely if the operator accepts the loss

Explanation

A leak rate above the defined limit means the system has a significant leak, which triggers an obligation to repair it without undue delay and then verify the repair by a further check. Topping up without repair leaves the emission ongoing. The duty applies regardless of flammability, and operator acceptance does not remove it.

Question 48F-gas certification of refrigeration technicians (category I)

During evacuation of a system before charging, a technician uses a vacuum gauge at the pump rather than at the system. Why is this poor practice?

  1. The gauge then measures the pump's performance instead of the vacuum actually reached in the system Correct answer.
  2. Vacuum gauges cannot be connected to service ports
  3. The pump connection is always at a higher temperature
  4. The system pressure is irrelevant during evacuation

Explanation

A gauge at the pump reads the vacuum at the machine, which may be far better than the vacuum in the circuit because of pressure drop and restrictions in the hose. The true test is the vacuum achieved and held in the system, measured at the system itself. Connection temperature and port compatibility are not the issue.

Question 49F-gas certification of refrigeration technicians (category I)

A technician plans to use a flammable refrigerant in a system located in a basement plant room. Which consideration is decisive for the design?

  1. The maximum permissible charge and ventilation provisions for the occupied space Correct answer.
  2. The refrigerant's global warming potential relative to CO2
  3. The colour of the pipework identification bands
  4. The warranty period offered by the compressor maker

Explanation

For flammable refrigerants the allowable charge is limited by the volume and ventilation of the space, and additional measures may be needed for occupied or below-ground rooms. Pipe marking and warranty terms are administrative matters. GWP affects environmental reporting but does not govern the flammable-charge safety limit.

Question 50F-gas certification of refrigeration technicians (category I)

A technician is asked to sign off a system where the only leak test performed was a soap-bubble check on visible joints. Why is this insufficient as the sole method for a formal leak check?

  1. Bubble testing measures pressure rather than leaks
  2. Soap solution damages copper pipework and must never be used
  3. Bubble testing is only valid for flammable refrigerants
  4. It only covers accessible joints and misses concealed parts, so it cannot confirm the whole circuit is leak-free Correct answer.

Explanation

A formal leak check must cover the parts of the circuit that can be reached and use suitable methods, including electronic detection where appropriate. Bubble solution on visible joints alone leaves concealed components unchecked, so it cannot support a statement that the system is leak-free. Soap solution does not harm copper, and it does detect leaks.