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ASE H7 HVAC (Transit Bus) study materials
ASE H7 HVAC (Transit Bus) study resources

ASE H7 HVAC (Transit Bus) practice questions

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Question 1HVAC System Fundamentals, Safety, and Regulations

On a transit bus air-conditioning system, what is the primary function of the refrigerant in the evaporator coil?

  1. Pressurize the cabin to prevent outside air infiltration
  2. Filter moisture and debris from the cabin air
  3. Release heat to the passenger compartment air as it condenses
  4. Absorb heat from the passenger compartment air as it boils Correct answer.

Explanation

The evaporator is the low-side heat exchanger where low-pressure liquid refrigerant boils and absorbs heat from air passing over the coil, cooling the cabin. Condensation and heat rejection occur at the condenser on the high side.

Question 2HVAC System Fundamentals, Safety, and Regulations

Which refrigerant is most commonly specified in modern North American transit bus HVAC systems because of its low ozone-depletion potential?

  1. R-134a Correct answer.
  2. R-12
  3. R-744 (CO2)
  4. R-22

Explanation

R-134a replaced R-12 in mobile air conditioning because it has zero ozone-depletion potential and became the standard for buses and light vehicles. R-12 is ozone-depleting and no longer used in new equipment.

Question 3HVAC System Fundamentals, Safety, and Regulations

A technician must recover refrigerant from a bus A/C system before opening it. Which statement reflects correct environmental practice?

  1. Refrigerant may be discharged into the engine exhaust stream
  2. Recovery is required only when the system charge exceeds 25 pounds
  3. Refrigerant must be recovered using certified recovery equipment Correct answer.
  4. Venting refrigerant to atmosphere is acceptable if the quantity is small

Explanation

Clean Air Act regulations require refrigerant to be recovered with certified equipment before service that opens the system, regardless of charge size. Knowing venting is prohibited is a core technician responsibility.

Question 4HVAC System Fundamentals, Safety, and Regulations

What is the purpose of the receiver-drier or accumulator in a bus A/C circuit?

  1. To store liquid refrigerant and remove moisture and contaminants Correct answer.
  2. To regulate blower motor speed
  3. To mix lubricating oil with cabin air
  4. To raise refrigerant pressure before the condenser

Explanation

The receiver-drier (or accumulator on orifice-tube systems) stores refrigerant, holds desiccant to absorb moisture, and filters debris. It protects the compressor and metering device from moisture and particles.

Question 5HVAC System Fundamentals, Safety, and Regulations

A bus operator reports weak cooling. The technician finds the blower runs but no air flows from the vents. Which is the most likely cause?

  1. A failed condenser fan
  2. A restricted or disconnected duct Correct answer.
  3. An overcharged system
  4. Low refrigerant charge

Explanation

If the blower operates but no air reaches the vents, the airflow path is blocked or disconnected, such as a collapsed duct or a disconnected plenum. Refrigerant charge affects temperature, not whether air moves.

Question 6HVAC System Fundamentals, Safety, and Regulations

Which safety hazard is most associated with servicing a bus A/C system that uses a flammable refrigerant?

  1. Reduced system efficiency
  2. Faster evaporator frosting
  3. Ignition risk near open flame or spark sources Correct answer.
  4. Increased compressor oil viscosity

Explanation

Flammable refrigerants such as R-1234yf can ignite when concentrated near ignition sources, so service areas must avoid open flames and sparks. This is a primary safety consideration during leak detection and repair.

Question 7HVAC System Fundamentals, Safety, and Regulations

What does the term 'superheat' describe in a bus A/C system?

  1. The temperature of refrigerant above its saturation point at a given pressure Correct answer.
  2. The total heat rejected by the condenser
  3. The amount of oil carried by the refrigerant
  4. The pressure drop across the condenser

Explanation

Superheat is the number of degrees a vapor is above its saturation temperature at the measured pressure. It confirms that refrigerant leaving the evaporator is fully vaporized before reaching the compressor.

Question 8HVAC System Fundamentals, Safety, and Regulations

Which regulation governs the handling and recovery of refrigerants used in motor vehicle air conditioning in the United States?

  1. EPA Tier 3 emissions rules
  2. Section 608 of the Clean Air Act Correct answer.
  3. FMVSS 302
  4. OSHA Hazard Communication Standard

Explanation

Section 608 of the Clean Air Act sets requirements for refrigerant handling, recovery, and technician certification for MVAC systems. It is the basis for the recovery and recycling rules technicians follow.

Question 9HVAC System Fundamentals, Safety, and Regulations

A technician measures 35 psig on the low side and 250 psig on the high side with the system running. Which condition best explains these readings?

  1. A restricted expansion device
  2. Normal operation for a properly charged system
  3. An overcharged system or restricted condenser airflow Correct answer.
  4. A failed compressor clutch

Explanation

High high-side pressure combined with an elevated low side typically indicates excess charge or poor condenser heat rejection, such as restricted airflow or a dirty coil. Normal systems run lower high-side pressures at moderate ambient.

Question 10HVAC System Fundamentals, Safety, and Regulations

Why must a bus A/C system be evacuated before charging?

  1. To test the compressor clutch
  2. To increase the refrigerant charge weight
  3. To remove moisture and non-condensable gases from the circuit Correct answer.
  4. To lubricate the expansion valve

Explanation

Evacuation with a vacuum pump removes air and boils off moisture that would otherwise form acids and ice at the metering device. A proper vacuum also verifies the system holds pressure.

Question 11HVAC System Fundamentals, Safety, and Regulations

What is the primary role of the condenser in a transit bus A/C system?

  1. To cool the passengers directly
  2. To meter refrigerant into the evaporator
  3. To store excess refrigerant
  4. To reject heat from the refrigerant to outside air Correct answer.

Explanation

The condenser is the high-side heat exchanger where compressed hot refrigerant vapor condenses and releases heat to ambient air. This heat rejection is essential for the cycle to continue cooling the cabin.

Question 12HVAC System Fundamentals, Safety, and Regulations

A bus A/C compressor clutch will not engage. Which electrical check should a technician perform first?

  1. Replace the expansion valve
  2. Verify clutch coil voltage and ground with the system commanded on Correct answer.
  3. Measure the cabin air filter restriction
  4. Recover the refrigerant charge

Explanation

When a clutch fails to engage, the first step is confirming the coil receives voltage and a good ground when commanded on, since a power or ground fault is common. Recovering charge or replacing parts before electrical diagnosis is premature.

Question 13HVAC System Fundamentals, Safety, and Regulations

What does a low-side pressure that drops below normal and stays there, with poor cooling, most likely indicate?

  1. A stuck-open compressor clutch
  2. A failed condenser fan
  3. A restricted expansion device or low refrigerant charge Correct answer.
  4. An overcharged system

Explanation

Low suction pressure with weak cooling points to insufficient refrigerant flow, either from a low charge or a restriction at the expansion device. Both reduce refrigerant entering the evaporator.

Question 14HVAC System Fundamentals, Safety, and Regulations

Which personal protective equipment is essential when handling liquid refrigerant during bus A/C service?

  1. No PPE is needed for small quantities
  2. Safety glasses and insulated gloves Correct answer.
  3. Hearing protection only
  4. A dust mask only

Explanation

Liquid refrigerant can cause severe frostbite and eye injury on contact, so safety glasses and insulated gloves are required. Proper PPE is a basic safety rule for refrigerant handling.

Question 15HVAC System Fundamentals, Safety, and Regulations

A technician wants to confirm the system holds a vacuum before charging. What result indicates an acceptable hold test?

  1. Vacuum drops to zero immediately
  2. Vacuum fluctuates with the blower speed
  3. Vacuum rises slowly and continues rising
  4. Vacuum holds steady with the pump isolated Correct answer.

Explanation

After evacuation, isolating the pump and observing a steady vacuum confirms the system is leak-free and dry. A rising vacuum indicates a leak or moisture boiling off.

Question 16HVAC System Fundamentals, Safety, and Regulations

What is the function of the expansion valve in a bus A/C system?

  1. It filters moisture from the refrigerant
  2. It meters refrigerant flow into the evaporator to control superheat Correct answer.
  3. It condenses refrigerant vapor
  4. It compresses refrigerant vapor

Explanation

The expansion valve throttles high-pressure liquid into the evaporator and modulates flow to maintain proper superheat at the evaporator outlet. This ensures full evaporation without liquid slugging the compressor.

Question 17HVAC System Fundamentals, Safety, and Regulations

A bus with dual-zone HVAC has cold air at one evaporator and warm air at the other. Which approach best isolates the cause?

  1. Immediately replace the compressor
  2. Compare refrigerant pressures and airflow at each zone circuit Correct answer.
  3. Replace the main blower motor
  4. Recover and recharge the entire system

Explanation

Comparing pressures and airflow between zones isolates whether the fault is refrigerant distribution or airflow-related in one circuit. Systematic comparison avoids replacing parts unnecessarily.

Question 18HVAC System Fundamentals, Safety, and Regulations

Which statement about non-condensable gases in a bus A/C system is accurate?

  1. They only affect low-side readings
  2. They raise high-side pressure and reduce cooling efficiency Correct answer.
  3. They are removed by adding more refrigerant
  4. They improve heat transfer at the condenser

Explanation

Non-condensables such as air cannot condense at normal condenser temperatures, so they raise head pressure and reduce efficiency. Proper evacuation prevents them from entering the system.

Question 19HVAC System Fundamentals, Safety, and Regulations

What is the purpose of the low-pressure switch in a bus A/C control circuit?

  1. To increase blower speed at high pressure
  2. To open the condenser fan relay at high pressure
  3. To regulate cabin temperature directly
  4. To disengage the compressor when suction pressure falls too low Correct answer.

Explanation

A low-pressure switch protects the compressor from running with insufficient refrigerant by disengaging the clutch when suction pressure drops below a set point. This prevents lubrication starvation and overheating.

Question 20HVAC System Fundamentals, Safety, and Regulations

A technician notices frost forming on the suction line right after the expansion valve on a bus A/C system. Which condition is most consistent with this symptom?

  1. A failed condenser fan
  2. An overcharge of refrigerant
  3. Excessive cabin airflow
  4. A restriction at the expansion valve or a low charge Correct answer.

Explanation

Frost just downstream of the metering device indicates a pressure drop that chills the line, often from a restriction or low charge causing excessive expansion. Proper diagnosis confirms with pressure readings.

Question 21HVAC System Fundamentals, Safety, and Regulations

Why is it important to use the refrigerant oil specified for the system when servicing a bus A/C compressor?

  1. Mismatched oil can impair lubrication and damage the compressor Correct answer.
  2. Oil is not required in modern systems
  3. Any oil improves cooling capacity
  4. Oil type affects only the color of the refrigerant

Explanation

Refrigerant oils are formulated for compatibility with specific refrigerants and materials; the wrong oil can fail to lubricate, cause sludge, or damage seals. Following the manufacturer's specification protects the compressor.

Question 22HVAC System Fundamentals, Safety, and Regulations

A technician is diagnosing intermittent cooling loss on a bus. Pressures are normal when cooling works, and the clutch disengages randomly. Which is the most likely cause?

  1. A permanently restricted expansion valve
  2. An empty refrigerant charge
  3. An intermittent electrical fault in the clutch circuit or a faulty pressure switch Correct answer.
  4. A completely failed compressor

Explanation

Intermittent clutch disengagement with otherwise normal pressures points to an intermittent electrical connection or a pressure switch cutting out. A hard failure like a restriction or empty charge would cause consistent symptoms.

Question 23HVAC System Fundamentals, Safety, and Regulations

During a performance test, a bus A/C system shows high suction and high discharge pressures with poor cooling. Which condition best fits these readings?

  1. A compressor with worn internal components Correct answer.
  2. A restricted condenser airflow
  3. An undercharge of refrigerant
  4. A faulty low-pressure switch

Explanation

High suction and high discharge with poor cooling can indicate a compressor that cannot build adequate pressure differential due to worn valves or pistons. Confirming with a performance test and pressure differential helps isolate internal wear.

Question 24HVAC System Fundamentals, Safety, and Regulations

A technician must replace a failed TXV on a bus A/C system. Which sequence reflects proper service practice?

  1. Add refrigerant, replace the valve, then evacuate
  2. Replace the valve with the system pressurized, then top off
  3. Vent refrigerant, replace the valve, then recharge by gauge only
  4. Recover refrigerant, replace the valve, evacuate, then recharge by weight Correct answer.

Explanation

Opening the system requires recovering refrigerant first, then replacing the component, evacuating to remove air and moisture, and charging to the specified weight. This sequence protects the system and complies with refrigerant rules.

Question 25HVAC System Fundamentals, Safety, and Regulations

A bus A/C system cools adequately at low speed but loses capacity at highway speed. Which cause is most consistent with this pattern?

  1. An oversized receiver-drier
  2. A condenser airflow or fan control issue that worsens with engine speed changes Correct answer.
  3. A stuck-open expansion valve
  4. A low refrigerant charge that only appears at idle

Explanation

Loss of capacity at higher speed often relates to condenser airflow or fan control that does not keep pace, raising head pressure and reducing cooling. Verifying fan operation and condenser condition is the diagnostic path.

Question 26HVAC System Fundamentals, Safety, and Regulations

Which refrigerant is classified as flammable and is used in some transit bus A/C systems?

  1. R-1234yf Correct answer.
  2. R-22
  3. R-410A
  4. R-134a

Explanation

R-1234yf carries a mild flammability rating (A2L) and requires special handling precautions in service. R-134a is nonflammable, and R-22 and R-410A are stationary-equipment refrigerants not used in transit bus A/C.

Question 27HVAC System Fundamentals, Safety, and Regulations

A technician must identify the type of refrigerant in an unfamiliar bus A/C system before service. Which method is the correct one?

  1. Read the underhood refrigerant label Correct answer.
  2. Check the color of the compressor oil
  3. Smell the refrigerant at the service port
  4. Compare fitting size to a known system

Explanation

The refrigerant identification label on the vehicle is the authoritative source for the refrigerant type and charge. Physical or sensory checks are unreliable and unsafe for identification.

Question 28HVAC System Fundamentals, Safety, and Regulations

A transit bus A/C system uses a refrigerant with an A2L classification. Which service practice applies when recovering the charge?

  1. Use recovery equipment rated for A2L refrigerants and eliminate ignition sources Correct answer.
  2. Recover the charge with standard R-134a equipment without modification
  3. Vent the charge to atmosphere because A2L is exempt from recovery rules
  4. Recover the charge only after the engine has run for 30 minutes

Explanation

A2L refrigerants require recovery equipment and procedures rated for flammable refrigerants, along with control of ignition sources. Recovery is mandatory, and equipment must be suitable for the refrigerant being handled.

Question 29HVAC System Fundamentals, Safety, and Regulations

A bus A/C system uses R-134a and the technician is checking charge level by weight. Which comparison is the correct reference?

  1. Charge weight listed on the vehicle specification label Correct answer.
  2. Charge weight printed on the refrigerant cylinder
  3. Charge weight shown on the manifold gauge set
  4. Charge weight stamped on the receiver-drier

Explanation

The vehicle specification label states the correct refrigerant charge for that bus. Cylinder labels show the contents of the container, not the system requirement.

Question 30HVAC System Fundamentals, Safety, and Regulations

A bus A/C system is being retrofitted from R-12 to R-134a. Which step is required before charging with the new refrigerant?

  1. Flush the system and install compatible oil and service fittings Correct answer.
  2. Increase the charge weight by 50 percent
  3. Retain the original mineral oil and fittings
  4. Add a second receiver-drier in series

Explanation

Retrofit requires removal of the original oil, installation of compatible lubricant, and change of service fittings to prevent cross-contamination. Original mineral oil and R-12 fittings are not compatible with R-134a.

Question 31Refrigerant Recovery, Recycling, and Handling

Under the mobile air conditioning rules, refrigerant that is recovered from a transit bus system must be handled in a way that does what?

  1. Allows it to vent if the quantity is small
  2. Permits dilution with shop air before storage
  3. Prevents its release into the atmosphere Correct answer.
  4. Requires it to be burned on site

Explanation

Recovered refrigerant must be captured and kept from escaping to the atmosphere; venting is prohibited regardless of charge size. The recovered gas is then either recycled, reclaimed, or stored for proper disposal.

Question 32Refrigerant Recovery, Recycling, and Handling

A recovery cylinder should never be filled beyond what limit of its capacity?

  1. 80 percent Correct answer.
  2. 100 percent
  3. 50 percent
  4. 95 percent

Explanation

Recovery cylinders are limited to about 80 percent of capacity by weight to leave room for liquid expansion and prevent hydrostatic rupture. The cylinder is normally charged and checked on a scale.

Question 33Refrigerant Recovery, Recycling, and Handling

Which document on a refrigerant cylinder identifies the type of refrigerant and its safety information?

  1. The cylinder label and safety data sheet Correct answer.
  2. The bus maintenance log
  3. The recovery machine manual
  4. The shop work order

Explanation

The cylinder label identifies the refrigerant, and the safety data sheet provides hazard and handling information. Both are required references before using or storing the cylinder.

Question 34Refrigerant Recovery, Recycling, and Handling

Before recovering refrigerant from a transit bus system, the technician should first do what?

  1. Open the service valves fully
  2. Start the engine and run the A/C
  3. Disconnect the battery cables
  4. Identify the refrigerant in the system Correct answer.

Explanation

Identifying the refrigerant prevents cross-contamination of recovery equipment and storage cylinders. Mixing refrigerant types makes the recovered charge unusable and can be hazardous.

Question 35Refrigerant Recovery, Recycling, and Handling

Refrigerant that has been recovered from a system and cleaned for reuse in the same system is best described as what?

  1. Reclaimed refrigerant
  2. Recycled refrigerant Correct answer.
  3. Virgin refrigerant
  4. Ventilated refrigerant

Explanation

Recycling is the on-site cleaning of recovered refrigerant for reuse, typically in the same equipment. Reclaiming is a more thorough process done to specification, often off site.

Question 36Refrigerant Recovery, Recycling, and Handling

What is the primary purpose of a refrigerant recovery machine?

  1. To filter debris from the compressor oil
  2. To measure the system's operating pressures
  3. To remove refrigerant from a system and store it in a cylinder Correct answer.
  4. To recharge a system with new refrigerant

Explanation

A recovery machine draws refrigerant out of the system and pushes it into a storage cylinder instead of the atmosphere. Charging, pressure measurement, and oil filtering are separate functions.

Question 37Refrigerant Recovery, Recycling, and Handling

A technician recovers refrigerant into a cylinder and notices the cylinder has no float switch or overfill sensor. How should the fill be controlled?

  1. By sound of the liquid
  2. By gauge pressure only
  3. By weight using a scale Correct answer.
  4. By time of recovery

Explanation

When a cylinder lacks an overfill device, the technician controls the fill by weighing the cylinder on a scale and stopping at the rated limit. Weight is the reliable measure of liquid quantity.

Question 38Refrigerant Recovery, Recycling, and Handling

Why must different refrigerants never be mixed in the same recovery cylinder?

  1. The cylinder will always rupture immediately
  2. The refrigerant will freeze solid in the cylinder
  3. The recovery machine will not start
  4. The mixture cannot be reclaimed to specification and may be hazardous Correct answer.

Explanation

Mixed refrigerants generally cannot be separated or brought back to a purity standard, so the entire cylinder becomes waste. Mixing can also create unexpected pressure and safety hazards.

Question 39Refrigerant Recovery, Recycling, and Handling

After recovering refrigerant, why should the recovery equipment be purged or the lines cleared before disconnecting?

  1. To minimize refrigerant released when the hoses are separated Correct answer.
  2. To warm the compressor oil
  3. To reset the recovery machine's timer
  4. To raise the system's operating pressure

Explanation

Refrigerant trapped in hoses and the machine is released when fittings are opened. Clearing or evacuating the lines into the recovery cylinder keeps that refrigerant from venting.

Question 40Refrigerant Recovery, Recycling, and Handling

A technician is storing a recovery cylinder between jobs. Which practice is correct?

  1. Lay the cylinder on its side in direct sunlight
  2. Leave the valve open to relieve pressure
  3. Cap the valves and store the cylinder upright and secured Correct answer.
  4. Store it uncapped near a heat source

Explanation

Recovery cylinders should be kept upright, secured against tipping, with valve caps installed to protect the fittings. They must be kept away from heat and direct sunlight.

Question 41Refrigerant Recovery, Recycling, and Handling

A recovery cylinder's gross weight is 60 lb empty and its rated capacity allows 30 lb of refrigerant. What is the maximum total weight on the scale at the 80 percent limit?

  1. 90 lb
  2. 60 lb
  3. 78 lb
  4. 84 lb Correct answer.

Explanation

Eighty percent of the 30 lb refrigerant capacity is 24 lb; adding the 60 lb tare weight gives 84 lb total. The scale reading includes both cylinder and refrigerant.

Question 42Refrigerant Recovery, Recycling, and Handling

During recovery, a technician should watch the system pressures and recovery rate because a sudden drop in recovery rate may indicate what?

  1. The refrigerant is changing type
  2. The system is nearly empty of liquid refrigerant Correct answer.
  3. The recovery machine has overheated
  4. The cylinder is overfilled with air

Explanation

As liquid refrigerant is removed, the recovery rate falls and the system approaches empty. Monitoring pressures and rate helps the technician know when recovery is essentially complete.

Question 43Refrigerant Recovery, Recycling, and Handling

Which personal protective equipment is most important when handling refrigerant and connecting recovery equipment?

  1. A dust mask
  2. Safety glasses and gloves Correct answer.
  3. Steel-toed boots only
  4. Hearing protection

Explanation

Refrigerant can cause frostbite and eye injury from rapid expansion and liquid contact, so eye and hand protection are essential. Gloves and safety glasses guard the areas most exposed during service.

Question 44Refrigerant Recovery, Recycling, and Handling

Refrigerant vapor is heavier than air. What does this mean for a technician working in a bus bay pit?

  1. Vapor can collect in low areas and displace breathable air Correct answer.
  2. Vapor rises quickly and clears the pit
  3. Vapor becomes harmless at floor level
  4. The pit is the safest place to recover refrigerant

Explanation

Because refrigerant vapor is denser than air, it can accumulate in pits and low spaces and displace oxygen. Good ventilation and awareness of low areas are important safety measures.

Question 45Refrigerant Recovery, Recycling, and Handling

A technician suspects a transit bus A/C system has a leak. Which action is appropriate before adding refrigerant?

  1. Locate and repair the leak, then evacuate and recharge Correct answer.
  2. Seal the leak with refrigerant stop-leak and skip repair
  3. Vent the remaining charge to check the leak
  4. Add refrigerant until the leak stops

Explanation

Refrigerant should not be added to a leaking system as a substitute for repair. The leak is found and fixed, then the system is evacuated and properly charged.

Question 46Refrigerant Recovery, Recycling, and Handling

Why is it important to evacuate a system after opening it for repair and before recharging?

  1. To cool the compressor windings
  2. To remove moisture and non-condensable gases Correct answer.
  3. To increase the refrigerant charge
  4. To lubricate the expansion valve

Explanation

Evacuation with a vacuum pump removes air and moisture that would otherwise cause acid formation and poor performance. A proper vacuum is part of correct service after any repair that opens the system.

Question 47Refrigerant Recovery, Recycling, and Handling

A recovery cylinder is labeled for R-134a but the technician is unsure of the system's refrigerant. What is the safest course of action?

  1. Recover into the R-134a cylinder anyway
  2. Identify the system refrigerant before recovering into any cylinder Correct answer.
  3. Vent a small sample to smell the refrigerant
  4. Recover into an unmarked cylinder

Explanation

Recovering an unknown refrigerant into a labeled cylinder risks contaminating it and creating an unusable mixture. The refrigerant must be identified first, often by label or identifier, before recovery.

Question 48Refrigerant Recovery, Recycling, and Handling

Which statement best explains why recovered refrigerant destined for reclaim must be kept clean and dry?

  1. Reclaimers cannot process liquid refrigerant
  2. Reclaimers require the refrigerant to meet a purity specification to be restored Correct answer.
  3. Reclaimers add water to the refrigerant during processing
  4. Reclaimers only accept refrigerant mixed with air

Explanation

Reclaiming restores refrigerant to a defined purity standard, so contamination such as moisture, air, or mixed refrigerant can make the batch unacceptable. Clean handling preserves the value and usability of the recovered charge.

Question 49Refrigerant Recovery, Recycling, and Handling

When transferring refrigerant from a recovery cylinder to a larger storage vessel, which safety practice applies?

  1. Overfill the receiving vessel to save trips
  2. Use a vessel rated for a different refrigerant
  3. Heat the receiving vessel to speed transfer
  4. Verify the receiving vessel's pressure rating and refrigerant compatibility Correct answer.

Explanation

The receiving vessel must be compatible with the refrigerant and rated for the pressures involved. Heating a vessel or using mismatched equipment creates serious pressure hazards.

Question 50Refrigerant Recovery, Recycling, and Handling

A recovery machine is not pulling the system down as expected. Which condition is a likely cause that the technician should check?

  1. The cylinder is too cold
  2. A restricted or leaking hose connection Correct answer.
  3. The compressor oil is new
  4. The system is already fully charged

Explanation

Loose or restricted hoses and fittings reduce the machine's ability to draw refrigerant and can leak it. Checking connections and hoses is a basic troubleshooting step before assuming equipment failure.