1
Q
What is the result when an evaporator is 25ft lower than the condenser?
A
- Oil traps in the liquid line
- Decrease in metering device capacity
- Liquid line diameter too large
- Increase in metering device capacity
The position of the evaporator relative to the condenser affects the system’s performance.
2
Q
What will occur if a metering device is oversized?
A
- Head pressure will remain constant
- Suction pressure will remain constant
- Evaporator superheat will fluctuate
- Evaporator superheat will remain excessive
Oversizing can lead to inefficiencies in the refrigeration cycle.
3
Q
What is the result of a compressor motor operating with a voltage exceeding the allowable upper and lower limits?
A
- low current
- high current
- high discharge pressure
- low discharge pressure
Operating outside voltage limits can cause significant operational issues.
4
Q
What would be required in a system having a non-bleed type TXV?
A
- A crankcase heater
- A run capacitor
- A low temperature cutout
- A hard start kit
Non-bleed TXVs require specific components for proper operation.
5
Q
Which of the following will close the Potential relay contacts?
A
- The loss of counter EMF when the compressor stops
- The increase of counter EMF from the run winding
- The increase of counter EMF when the compressor starts
- The initial amperage of the run winding
Understanding relay operation is crucial for troubleshooting.
6
Q
What is the indoor comfort goal for conditioned air in the summer?
A
- 600F wet bulb and 35% relative humidity
- 650F dry bulb and 40% relative humidity
- 700F wet bulb and 45% relative humidity
- 750F dry bulb and 50% relative humidity
These parameters help maintain comfort levels in indoor environments.
7
Q
What is the force that causes a reversing valve to shift from heating to cooling?
A
- The magnetism of the reversing solenoid coil
- The difference between high and low side system pressures
- Temperature differential across the valve
- Solenoid coil voltage
The operation of the reversing valve is essential for heat pump functionality.
8
Q
How should an off cycle-self regulating crankcase heater be connected to a new 2 pole contactor?
A
- Ll wire to the line side of one of the poles, and the L2 wire to the load side of the opposite pole, Compressor common to Tl of contactor, then reroute the compressor wire of the opposite pole to the load side of the contactor.
- Ll wire to the line side of one of the poles, and the L2 wire to the line side of the opposite pole, Compressor common to Tl of contactor, then re-route the compressor wire of the opposite pole to the load side of the contactor.
- Both compressor wires to the load side of the contactor.
- Both compressor wires to the line side of the contactor.
Proper wiring is critical for the safe operation of the crankcase heater.
9
Q
When joining copper to steel, what is the visual clue that you can apply the filler alloy?
A
- The flux has dried and becomes a white powder or crust
- The flux has become a bubbling milky white
- The flux has become a clear liquid
- The flux has disappeared (it is still present; just not visible)
Recognizing the right moment to apply filler alloy is essential for effective soldering.
10
Q
What would be the result of a zone damper that fails to open?
A
- low suction pressure when a heat pump is in cooling mode
- low suction pressure when a heat pump is in heating mode
- high suction pressure when a heat pump is in cooling mode
- freeze up of an air source heat pump’s outdoor coil
A malfunctioning zone damper can lead to significant system inefficiencies.
11
Q
What is the result of a reversing valve that has an internal leak?
A
- Decrease in compressor suction pressure
- Increases the liquid temperature in the evaporator
- Decreases the liquid temperature in the condenser
- Decrease in compressor discharge pressure
Internal leaks can severely impact system performance.
12
Q
What is the purpose of the condenser?
A
- Reject Net Refrigeration Effect
- Reject heat of compression
- Reject heat of liquification, heat of compression and NRE
- Reject suction line superheat, heat of compression and NRE
The condenser plays a crucial role in the refrigeration cycle.
13
Q
Which of the following would you not find on a typical air source heat pump outdoor section?
A
- A capacitor
- A defrost control
- A reversing valve
- A blower relay
Understanding the components of heat pumps is essential for maintenance and troubleshooting.
14
Q
What is the capacity of a coil having the following conditions? airflow = 200 cfm, enthalpy entering the coil = 30.0 Btu/lb, enthalpy leaving the coil = 23.2 Btu/lb and specific volume leaving the coil = 13.155 cubic feet per pound?
A
- 1,360 Btu/hr
- 6,201 Btu/hr
- 20,672 Btu/hr
- 23,769 Btu/hr
Calculating coil capacity is essential for system design and efficiency.
15
Q
Of the following gases, what is the most dangerous to use for pressure testing?
A
- Nitrogen
- Oxygen
- Carbon dioxide
- HCFC 410A
Safety considerations are paramount when working with refrigerants and gases.
16
Q
Is it acceptable and appropriate practice to install an A coil in the return air plenum of a furnace?
A
- No, because the heat exchanger will sweat and rust
- No, because ‘A’ coils work better when air is pushed through not pulled through
- Yes, if the installation is a heat pump added on to an existing electric forced air furnace
- Yes, but most return air plenums are narrow; it is easier to install ‘A’ coils in the supply plenum
Proper installation practices are crucial for system longevity and performance.
17
Q
Which of the following statements is true?
A
- Liquid lines should be cooler than suction lines
- Liquid lines have more heat content in them than suction lines
- Hot gas discharge lines have the greatest heat content
- All of the above
Understanding the thermal properties of refrigerant lines is essential for system efficiency.
18
Q
What is the problem when an R410A system has a suction pressure of 34 PSIG and a head pressure of 198 PSIG with a suction line temperature of 630F and there is a small amount of frost at the end of the cap tubes?
A
- Major loss of charge
- Minor loss of charge
- Restricted cap tubes
- Inefficient compressor
Diagnosing pressure issues is critical for effective system repair.
19
Q
What is the maximum number of throws a relay may have?
A
_______
Understanding relay specifications is important for electrical system design.
20
Q
What is the result of outside fresh air being introduced for ventilation purposes?
A
- humidifies the building in the summer time
- humidifies the building in the winter time
- decreases latent load for air conditioning
- decreases latent load for heating season
Ventilation strategies must consider seasonal impacts on indoor air quality.
21
Q
What is the nominal evaporator CFM required for a 3 ton air conditioning system?
A
- 200
- 400
- 1,200
- 12,000
Proper airflow is essential for effective cooling performance.
22
Q
The deep vacuum is measured with a micron gauge, how many microns are in 1 inch?
A
- 760
- 1,000
- 25,400
- 760,000
Understanding vacuum measurements is critical for refrigeration service.
23
Q
Which of the following will cause liquid refrigerant to hang up in the condenser?
A
- A metering device that is too restrictive
- Low condenser air flow with high ambient
- High condenser ambient
- Excessive evaporator air flow
Identifying causes of refrigerant issues is essential for system efficiency.
24
Q
What will happen to the air as the space humidity rises?
A
- Air temperature difference across evaporator will increase
- Air temperature difference across evaporator will remain unchanged
- Air temperature difference across evaporator will decrease
- Air density will increase as it enters the evaporator
Humidity levels significantly affect air conditioning performance.
25
What procedure must be done if the interconnecting line set length is greater than the standard length?
* Consult the manufacturers wiring manual for guidelines
* Increase the suction line and liquid line by 1 pipe size and add some refrigerant
* Simply reduce the suction line and liquid line by 1 pipe size and add some refrigerant
* Consult Installation Operation Manual for appropriate guidelines
## Footnote
Following manufacturer guidelines is crucial for system performance.
26
What will be the approximate **HFC 410A** liquid pressure at the metering device inlet if the liquid line rises 50ft and the pressure at the condenser outlet is 316 PSIG?
* 291 PSIG
* 316 PSIG
* 341 PSIG
* 356 PSIG
## Footnote
Pressure calculations are essential for system diagnostics.
27
Which is the configuration for a **reversing valve**?
* One pipe connected to the compressor and one connected to the condenser and two connected to the evaporator
* Two pipes connected to the compressor and one connected to the condenser and one connected to the evaporator
* One pipe connected to liquid, one pipe connected to vapor, one pipe to connected to suction, and one pipe connected to discharge
* Has one pipe connected to compressor discharge, one connected to compressor suction, one pipe connected to metering device, one pipe connected to condenser
## Footnote
Understanding the configuration of components is essential for troubleshooting.
28
Which of the following would not be found on a **ground source heat pump** system?
* A control transformer
* A defrost control
* A reversing valve
* A blower relay
## Footnote
Knowledge of system components is crucial for effective maintenance.
29
Which will cause abnormally low suction pressure?
* Poor compressor valves
* A broken TEV spring
* A broken TEV sensing bulb line
* A TEV using an external equalizing line
## Footnote
Identifying causes of suction pressure issues is critical for system performance.
30
Which is the correct statement regarding **TXVs**?
* Spring opens, bulb closes, evaporator pressure closes
* Spring closes, bulb closes, evaporator pressure opens
* Spring opens, bulb opens, evaporator pressure opens
* Spring closes, bulb opens, evaporator pressure closes
## Footnote
Understanding TXV operation is essential for effective refrigeration management.
31
How many watts are required to operate a **2 hp motor** for a period of 1 hour?
* 746 watts
* 1000 watts
* 1492 watts
* 3412 watts
## Footnote
Calculating power requirements is essential for electrical system design.
32
Which drawing shows the correct **compressor motor wiring configuration**?
_______
## Footnote
Understanding wiring configurations is crucial for safe and effective operation.
33
What is the correct statement regarding the **external equalizing line** as found on a TXV?
* Liquid line and conveys condenser outlet pressure to the top of the valve's diaphragm, giving a closing influence to the valve
* Suction line and conveys evaporator outlet pressure to the bottom of the valve's diaphragm, giving a closing influence to the valve
* Suction line and conveys evaporator outlet pressure to the bottom of the valve's diaphragm, giving an opening influence to the valve
* Suction line and conveys evaporator inlet pressure to the bottom of the valve's diaphragm, giving an opening influence to the valve
## Footnote
Understanding the function of equalizing lines is essential for TXV operation.
34
The ohm readings taken from a hermetic compressor are 12 ohms from R to ground, 6 ohms from C to ground, 6 ohms from S to ground, 18 ohms from R to S, 6 ohms from R to C and 12 ohms from S to C. What does this indicate?
* The compressor has a small short to ground halfway through the run winding
* There is a small short to ground halfway through the start winding
* There is a small short to ground halfway through common winding
* There is a small short to ground in the internal overload
## Footnote
Diagnosing electrical issues is critical for compressor functionality.
35
At what temperature does **copper tubing** glow reddish in color?
* 16000 F
* 1700 0F
* 18000F
* 19000F
## Footnote
Understanding the properties of materials is essential for effective soldering.
36
If indoor dry bulb is 730F and WB is 680F and the customer complains that they feel cool and clammy, what could be the issue?
* Air flow through the evaporator is too low
* System is oversized
* Evaporator coil is undersized
* Expansion valve superheat is adjusted to 100F to 120F
## Footnote
Diagnosing comfort issues is essential for effective HVAC performance.
37
What can be used to increase the pressure differential across the **expansion device** during low ambient operation?
* Condenser Fan Cycling Control
* Variable Speed Condenser Fan Motor
* Condenser Flooding
* All of the above
## Footnote
Understanding operational strategies is crucial for system efficiency.
38
What is the correct mounting procedure of the **thermostatic element bulb** to ensure proper control of the **TEV**?
* Clean discharge tubing, secure with nylon wrap and insulate
* Clean discharge tubing, secure with a metal clamp and insulate
* Clean suction line tubing adjacent to compressor, secure with similar metal clamp and insulate
* Clean horizontal evaporator outlet tubing after suction header, secure with similar metal clamp and insulate
## Footnote
Proper installation of the thermostatic element is critical for TEV performance.
39
What happens when a **hermetic compressor motor** is started?
* voltage rise, current rise
* voltage constant, current rise
* voltage drop, current constant
* voltage drop, current rise
## Footnote
Understanding motor behavior during startup is essential for troubleshooting.
40
What happens when a **split phase hermetic compressor motor** starts?
* auxiliary winding creates increased magnetic field and provides direction of rotation for main winding
* auxiliary winding creates increased magnetic field and provides direction of rotation for rotor and main winding maintains magnetic field
* main winding creates increased magnetic field and provides direction of rotation for auxiliary winding
* main winding creates increased magnetic field and provides direction of rotation for rotor and auxiliary winding maintains magnetic field
## Footnote
Understanding motor operation is critical for effective HVAC system design.
41
What current would be drawn upon the mechanical failure of a **hermetic compressor motor**?
* FLA
* 1 to 3 FLA
* 4 to 6 x LRA
* 4 to 6 x FLA
## Footnote
Understanding current draw is essential for diagnosing compressor issues.
42
Which describes the **air to air heat pump defrost cycle**?
* Cooling cycle with the outdoor fan running in reverse
* Heating cycle with the indoor fan temporarily shut off
* Cooling cycle with the outdoor fan temporarily shut off
* Heating cycle with the outdoor fan running in reverse
## Footnote
Understanding defrost cycles is essential for heat pump operation.
43
Which will result in an increase in **Volumetric efficiency**?
* Head pressure increase
* Head pressure decrease
* The TXV closes
* The indoor temp falls
## Footnote
Understanding volumetric efficiency is critical for system performance.
44
What is the purpose of a **crankcase heater**?
* To keep liquid refrigerant from accumulating in the compressor
* To keep the motor windings active
* To keep compressor pressure high when the system is off
* All of the above
## Footnote
Crankcase heaters are essential for preventing compressor damage.
45
What percentage capacitance variance is permitted of a **capacitor** compared with its nameplate?
* 15%
* 20%
## Footnote
Understanding capacitor specifications is important for electrical system reliability.
46
What would cause a system to operate in heating and cooling mode at the same time?
* Contactor stuck closed
* High ambient temperature
* Shorted thermostat
* Shorted fan relay contacts
## Footnote
Diagnosing control issues is critical for effective HVAC operation.
47
What is the combined rating of two **capacitors** wired in parallel and having the following individual ratings 20MFD@240VAC and 15MFD@370VAC?
* 35MFD@370VAC
* 8.6MFD@240VAC
* 35MFD@240VAC
## Footnote
Understanding capacitor configurations is essential for electrical system design.
48
What is the combined rating of two **capacitors** wired in series and having the following individual ratings Capacitors 20MFD@370VAC and 15MFD@240VAC?
* 35MFD@370VAC
* 8.6MFD@240VAC
* 8.6MFD@370VAC
* 35MFD@740VAC
## Footnote
Understanding series and parallel configurations is crucial for capacitor applications.
49
Which describes the opening of the **potential starting relay contacts**?
* Line voltage opens and start winding back EMF maintains open
* Counter EMF from the start winding opens and voltage above line voltage maintains open
* The loss of counter EMF from start winding when the compressor stops
* Increase in run winding EMF and back EMF of start winding maintains open
## Footnote
Understanding relay operation is essential for effective system control.
50
What is the difference between an **HRV** and an **ERV**?
* An HRV uses enthalpic paper and recovers both latent and sensible heat but an ERV only recovers latent heat
* An ERV uses a metal heat exchanger and recovers both latent and sensible heat but an HRV only recovers sensible heat
* An ERV uses enthalpic paper and recovers both latent and sensible heat and an HRV recovers sensible heat only
* An HRV uses a metal heat exchanger and recovers sensible heat and an ERV only recovers latent heat
## Footnote
Understanding the differences between HRVs and ERVs is crucial for energy recovery ventilation.
51
Shortly after the installation of an **electronic air cleaner (EAC)**, a customer complains that there is a noticeable, irritating ozone smell in the hall of the house. Which of the following would cause this problem?
* The installing technician neglected to interlock the EAC with the condensing unit
* The installing technician should have selected a lower CFM for blower low speed
* EAC not interlocked with supply fan
* Outdoor ventilation is set too low
## Footnote
Proper installation practices are essential for preventing issues with air quality.
52
What will low condenser air flow at outdoor design conditions result in?
* Partial evaporator frosting
* Increase in suction pressure
* Head pressure will decrease
* Compressor amperage will decrease
## Footnote
Understanding airflow impacts is critical for system performance.
53
Which of the following can cause an **evaporator** to freeze-up?
* Clogged condenser
* Bypass type humidifier
* Reversing valve leaking internally
* Oversized furnace blower motor
## Footnote
Identifying causes of freeze-up is essential for effective HVAC maintenance.
54
Which of the following can cause **compressor RLA** to rise?
* Supply fan wheel installed backwards
* Condenser fan turning backwards
* Insufficient air flow across evaporator
* A faulty cooling anticipator
## Footnote
Understanding the factors affecting compressor load is critical for troubleshooting.
55
What is illustrated by the **pictorial electrical diagram**?
* Sequence of operation
* Location of electrical components
* Component model number
* Component model number and serial number
## Footnote
Diagrams are essential for understanding system layout and operation.
56
What is the function of a **ladder electrical diagram**?
* Sequence of operation
* Location of components
* Component model number
* Component model number and serial number
## Footnote
Ladder diagrams are crucial for electrical troubleshooting.
57
Which statement is correct with regards to the thermostat **'C' terminal**?
* Is energized only during a call for heat
* Is energized only during a call for cooling
* Is constantly energized with 24 VAC (grounded)
* Is constantly energized with 24 VAC (ungrounded)
## Footnote
Understanding thermostat terminals is essential for HVAC control systems.
58
Which statement is correct with regards to the thermostat **'Y' terminal**?
* Is energized only during a call for heat
* Is energized only during a call for cooling
* Is constantly energized with 24 VAC
* Powers the fan relay
## Footnote
Understanding thermostat functions is crucial for effective HVAC operation.
59
Which statement is correct with regards to the thermostat **'R' terminal**?
* is energized only during a call for heat
* Is energized only during a call for cooling
* Is constantly energized with 24 VAC (often grounded or common)
## Footnote
Understanding the role of the 'R' terminal is essential for HVAC control.
60
Which statement is correct with regards to the thermostat **'Y' terminal**?
* Is energized only during a call for heat
* Is energized only during a call for cooling
* Is constantly energized with 24 VAC
* Powers the fan relay
## Footnote
The 'Y' terminal is crucial for controlling the cooling function of the HVAC system.
61
Which statement is correct with regards to the thermostat **'R' terminal**?
* Is energized only during a call for heat
* Is energized only during a call for cooling
* Is constantly energized with 24 VAC (often grounded or common)
* Is energized with 24 VAC (ungrounded)
## Footnote
The 'R' terminal provides power to the thermostat.
62
Which statement explains the **cooling anticipator**?
* Adjustable, energized during a call for cooling, and parallel with the temperature control
* Non-adjustable, energized during stand-by for cooling, and in series with the temperature control
* Non-adjustable, energized during stand-by for cooling, and parallel with the temperature control
* Adjustable, energized during a call for cooling and in series with the temperature control
## Footnote
The cooling anticipator helps regulate the cooling cycle of the HVAC system.
63
Which TXV port design is intended for operation with **floating head pressure**?
* Balanced port
* Conventional port
* Directional port
* Eccentric port
## Footnote
The design of the TXV affects its performance under varying pressure conditions.
64
What is the best way to test the **limit switch** on a furnace after installing a fan control center?
* Enable the blower, set the thermostat to call for heat and set the fan switch to the 'auto' position
* Disable the blower, set the thermostat to call for heat and set the fan switch to the 'off' position
* Disable the blower, set the thermostat to call for heat and set the fan switch to the 'auto' position
* Enable the blower, set the thermostat to call for heat and set the fan switch to the 'off' position
## Footnote
Proper testing ensures the limit switch functions correctly for safety.
65
What happens to a **reciprocating compressor** when the suction service valve is completely front seated?
* Compressor crankcase pressure should draw into a vacuum if high pressure switch is set correctly
* Compressor is operating in an unsafe condition and high pressure switch has failed
* Compressor crankcase pressure should draw into a vacuum if the low pressure switch cut out is set low enough
* Compressor crankcase pressure should draw into a vacuum if the low pressure switch cut in is set high enough
## Footnote
Understanding the compressor's behavior is critical for troubleshooting.
66
Which of the following is an acceptable **vacuum level measurement**?
* 1000 microns
* 29.9 PSIA
* 29.9 PSIG
* 500 microns
## Footnote
Vacuum measurements are essential for ensuring proper system operation.
67
Which refrigerant used for air conditioning must be transferred from the cylinder in the **liquid phase**?
R22
## Footnote
Transferring refrigerants in the correct phase is crucial for system performance.
68
What does a **fan control center** do when installing AC onto an older style of furnace?
* Step up transformer and single pole - double throw relay
* Step down transformer and a single pole - double throw relay
* Step down transformer and a double pole - single throw relay
* Step up transformer and a double pole - single throw relay
## Footnote
The fan control center is necessary for compatibility with older systems.
69
Which will result in **low suction pressure** within an Air conditioning system?
* Oversized ductwork
* Dirty condenser coils
* High humidity
* Dirty evaporator coils
## Footnote
Identifying causes of low suction pressure is important for system efficiency.
70
What type of **air distribution system** is used in residential buildings where air pressure remains steady from one end to the other?
* Radial duct system
* Reducing plenum system
* Perimeter loop system
* Flex duct
## Footnote
The design of the air distribution system affects airflow and efficiency.
71
What is the **minimum gauge metal** to be used when installing 8" x 20" galvanized rectangle duct?
16 gauge
## Footnote
Proper gauge ensures structural integrity and performance.
72
Which condition will cause the **compressor to seize**?
* 105 0F SCT, SST
* Excessive condenser air flow
* Restricted air filters
* -S OF subcooling and 120F evaporator superheat
## Footnote
Understanding these conditions is vital for compressor longevity.
73
What is the purpose of the **middle tab** on the dial of a conventional fan/limit control?
* Turning the fan off
* Turning the fan on
* High temp limit
* High temp reset
## Footnote
The middle tab is a key feature for controlling fan operation.
74
Which of the following must be considered when installing air conditioning on an **old furnace**?
* Check the fan motor horsepower and consider installing a smaller motor and pulley
* Check for a blower relay and install one if none is present
* Check for a 40VA transformer and install one if none is present
* Check for an isolation transformer and install one if none is present
## Footnote
Ensuring compatibility with existing systems is crucial for performance.
75
How are **heat anticipators** connected?
* In series with the gas valve and parallel with the temperature control
* In parallel with the gas valve and series with the temperature control
* In series with the gas valve and series with the temperature control
* In parallel with the gas valve and series with the temperature control
## Footnote
Proper connection is essential for accurate temperature regulation.
76
Which statement is correct regarding the conventional **fan/limit combination control**?
* Has normally open contacts on the limit side
* Has normally closed contacts on the fan side
* May be used with 24 volts only when the jumper is left intact
* It is thermally activated
## Footnote
Understanding the control's operation is important for HVAC systems.
77
Which of the following represents the **standard configuration** for residential supply power?
* 208/115 VAC, 3 phase, 60 Hz
* 240/120 VAC, 1 phase, 50 Hz
* 240/120 VAC, 2 phase, 60 Hz
* 240/120 VAC, 1 phase, 60 Hz
## Footnote
Knowing the standard configuration is essential for electrical compatibility.
78
Which meter type is used for measuring **electromotive force**?
* A Meggohm meter
* An ohm meter
* An amp meter
* A volt meter
## Footnote
The correct meter type is crucial for accurate measurements.
79
Which is the correct procedure when checking a **switch or contact continuity**?
* Disconnect power from the circuit so that magnetism does not damage the meter
* Disconnect power from the circuit so that voltage does not damage the meter
* Leave the power connected so that the test will be valid
* Disconnect power from the circuit and open contacts
## Footnote
Proper procedure ensures safety and accuracy during testing.
80
What happens when **copper and aluminum fins** are cleaned with an acidic cleaner?
* Transfer of copper electrons to aluminum
* Erosion
* Transfer of aluminum electrons to copper
* Electroplating
## Footnote
Understanding the chemical reactions is important for maintenance.
81
What is **Electricity** the flow of?
* Bound electrons
* Discharged electrons
* Inner valence electrons
* Outer valence electrons
## Footnote
Understanding the nature of electricity is fundamental in HVAC systems.
82
Which statement is correct with regards to **condensate drain lines**?
* Must be vented, trapped at a depth greater than the air pressure at the coil and directly connected to a drain
* Must be directly draining into a trapped drain
* Must be directly connected to an untrapped drain
* Must be vented, trapped at a depth less than the air pressure at the coil and directly connected to a drain
## Footnote
Proper installation prevents drainage issues.
83
What affects the **suction saturation temperature** of an air source heat pump while in the heating mode?
* Directly influenced by the house supply air temp
* Indirectly influenced by the outdoor air temp
* Does not vary, remains a constant 250F
* Does not vary, remains a constant 270F
## Footnote
Understanding these influences is key for system efficiency.
84
What is the maximum **liquid level**, at standard conditions, that should never be exceeded when filling a cylinder with a 400 series refrigerant?
* 70%
* 80%
* 90%
* 100%
## Footnote
Adhering to these levels is crucial for safety.
85
Which describes **refrigerant recycling**?
* Thoroughly restore refrigerant to exceptional purity by various processes of filtration, dehydration, distillation; achieving approved specifications
* Merely remove it from a system, distill the oil out and store it in an approved cylinder
* Remove refrigerant from a system, clean refrigerant for reuse by filtering it repeatedly through filter/driers
* Remove refrigerant from a system, separate the oil and clean refrigerant for reuse by filtering it repeatedly through filter/driers
## Footnote
Understanding recycling processes is essential for environmental compliance.
86
What is the **RPM** of an 8 inch pulley if the 4 inch drive pulley is rotating at 1720 RPM?
* 6880
* 860
* 720
* 645
## Footnote
Calculating RPM is important for system performance.
87
Considering the **first law of thermodynamics**, it is valid to say?
* Heat - as a form of energy - cannot be created or destroyed
* Heat - as a form of energy - cannot be converted to any other form
* Heat can only flow up or rise against gravity
* None of the above
## Footnote
Understanding thermodynamics is fundamental in HVAC systems.
88
Which statement is correct regarding the **boiling point of water**?
* An increase in atmospheric pressure will decrease the boiling point of water
* A decrease in atmospheric pressure will decrease the boiling point of water
* A change in atmospheric pressure has no effect on the boiling point of water
* The boiling point of water, in a closed vessel, will increase with a decrease in surrounding ambient temperature
## Footnote
Understanding boiling points is crucial for HVAC applications.
89
Which is an indication of correct **superheat adjustment**?
* Supply air off coil at 550F and 50% RH
* Supply air off coil at 750F and 50% RH
* Supply air off coil at 750F and 95% RH
* Supply air off coil at 550F and 95% RH
## Footnote
Correct superheat adjustment is vital for system efficiency.
90
What type of **copper tube** is used for air conditioning piping for pipe sizes of less than 1.125"?
* Type 'K' ACR
* Type 'L' ACR
* Type 'M' ACR
* Type 'G' ACR
## Footnote
Selecting the correct type of copper tube is essential for system integrity.
91
What tool is used for a **brazed connection** of two copper pipes when no coupling is available?
* Flaring tool
* Swaging tool
* Reducing coupling
* Joiner tool
## Footnote
Proper tools are necessary for effective connections.
92
What is the purpose of **purging with nitrogen** during brazing?
* Increase copper oxide formation
* Produce carbon formation on the inside of the piping
* Decrease oxides on piping outer wall
* Decrease oxides within piping
## Footnote
Purging is essential for maintaining clean piping during brazing.
93
What corrective action should be taken when you discover a **zone damper actuator motor** is seized?
* Disconnect the linkage and brace the damper in the open position
* Disconnect the linkage and brace the damper in the closed position
* Remove the damper, disconnect and terminate all wires
* Replace the motor, reactivate and test the damper
## Footnote
Addressing actuator issues is critical for system operation.
94
What will happen if a **condenser water regulating valve** for a condenser becomes restricted?
* Compressor amperage will fall
* Compressor amperage will rise
* Compressor amperage will not be affected
* Compressor amperage will rapidly fluctuate
## Footnote
Understanding the effects of restrictions is vital for compressor performance.
95
What type of **hermetic compressor** does not use a starting relay?
* PSC
* CSIR
* CSCR
* Shaded Pole
## Footnote
Knowing compressor types is essential for troubleshooting.
96
A unit rating plate for an R22 TXV system declares **Superheat** = 1 suction OF pressure and also declares **Subcooling** = 10F. What is the first thing you should do?
* Add refrigerant
* Remove refrigerant
* Turn the TXV in
* Turn the TXV out
## Footnote
Proper actions depend on system readings.
97
What procedure is performed when a **return bend leaks** on an evaporator coil?
* Replace the evaporator coil
* Repair the evaporator coil
* Clean the evaporator coil
* Calculate superheat
## Footnote
Addressing leaks promptly is crucial for system efficiency.
98
What 2 terminals will have a **jumper** at the thermostat in a system having one control transformer?
* Y and G
* Rc and Rh
* Rh and Y
* Rc and G
## Footnote
Understanding terminal configurations is essential for thermostat functionality.
99
What is the purpose of a **fuse**?
* Protect a motor after a burnout
* Control excessive current with resistance
* Modulate current by decreasing voltage
* Protect the building wiring from overheating
## Footnote
Fuses are critical for electrical safety.
100
What is the **condenser TD** for the following conditions?
Refrigerant: R22
Suction pressure = 75 psig
Discharge pressure = 225 psig
Metering device type: TEV
OD temp: 800F DB - 710F WB
Air off condenser: 1000F ID temp: 740F DB - 620F WB
* 200F
* 300F
* 740F
* 800F
## Footnote
Understanding temperature differences is crucial for system performance.
101
When a **water/refrigerant heat exchanger** is experiencing a high AT on the water side, it is an indication of:
* Poor flow
* Excessive flow
* Scaled tubes
* Overcharge of refrigerant
## Footnote
Identifying issues with heat exchangers is essential for efficiency.
102
What is the recommended maximum **suction line temperature** entering a compressor with a SST of 440F?
* 500F
* 550F
* 600F
* 650F
## Footnote
Maintaining proper temperatures is vital for compressor operation.
103
When the **suction line is covered in ice**, it is an indication of:
* Refrigerant flooding back
* Low suction pressure
* SST below 0F
* Suction line is below 320F
## Footnote
Recognizing these signs is crucial for troubleshooting.
