Unit 43 Test and Quiz Review
C
A dirty air filter will cause which of the following sets of conditions? A. Low suction pressure in heating, high discharge pressure in cooling B. Low suction pressure in both heating and cooling C. High discharge pressure in heating, low suction pressure in cooling D. High discharge pressure in both heating and cooling
?
A dirty outdoor coil will cause which of the following sets of conditions A. Low suction pressure in heating, high discharge pressure in cooling B. Low suction pressure both heating and cooling C. High discharge pressure in heating, low suction pressure in cooling D. High discharge pressure in both heating and cooling
True
A refrigerant coil must be located in the airstream before the auxiliary heating coil True or False
?
A reversing valve that is leaking internally will A. cause the high-side pressure to increase and the low-side pressure to drop B. cause the high-side pressure to decrease and the low side pressure to rise C. cause the compressor to run cold and pump excessive amounts of refrigerant D. cause the compressor to run hot and pump excessive amounts of refrigerant
B
A reversing valve that relies on the system's operating pressures to change the position of the valve is called a A. direct-acting reversing valve B. pilot-operated reversing valve C. indirectly controlled reversing valve D. pressure-activated reversing valve
A
A shorted load will result in A. reduced resistance and increased current flow B. reduced resistance and decreased current flow C. increased resistance and increased current flow D. increased resistance and decreased current flow
False
A typical air-to-air heat pump will have a COP of 2:5:1 at a 0 degrees F outdoor ambient temperature True or False
A
A typical electrical circuit is made up of A. a power supply, complete path for current, switches, and a load B. a power supply, a complete path for current, and a switch C. a complete path for current, a switch, and a load D. a current path to the load, a current path from the load, and a switch
C
A wind blowing off a lake will be very humid and might cause _________________________ when the system operates in heating mode A. excessive suction pressure B. excessive head pressure C. excessive outdoor freezing D. hot discharge air to be recirculated into the coil
C
An air-to-air heat pump operating in the heating mode might experience which of the following if it is installed in an area that is near a lake or other body of water? A. Higher than normal suction pressure B. Higher than normal discharge pressure C. Excessive ice buildup on the outdoor coil D. Shortened defrost cycles
C
An air-to-water heat pump system uses heat contained in A. water to cool air B. water to heat air C. air to heat water D. air to cool water
D
As an inverter-controlled compressor speeds up A. the suction pressure and the discharge pressure drop B. the suction pressure and the discharge pressure rise C. the suction pressure rises and the discharge pressure drops D. the suction pressure drops and the discharge pressure rises
D
At design voltage, how much heat will a 5-kW electric strip heater produce? A. 3413 Btu/h B. 6826 Btu/h C. 13,652 Btu/h D. 17,065 Btu/h
D
During defrost, what percentage of the heat pump system's cooling capacity should be offset by the electric heaters? A. 20% B. 40% C. 60% D. 80%
?
During the defrost cycle of an air-to-air heat pump system A. the outdoor fan remains on and some strip heaters turn on B. the outdoor fan remains on and all strip heaters turn on C. the outdoor fan cycles off and some strip heaters turn on D. the outdoor fan cycles off and all strip heaters turn on
B
During the defrost cycle of an air-to-air heat pump system A. the reversing valve coil is energized and the compressor cycles off B. the reversing valve coil is energized and the outdoor fans cycles off C. the reversing valve coil is deenergized and the compressor cycles off D. the reversing valve coil is deenergized and the outdoor fans cycles off
C
How can a system be easily identified as a heat pump simply looking at the thermostat? A. Heat pump thermostats have both heating and cooling settings B. Heat pump thermostats have a FAN-ON, FAN-AUTO feature C. Heat pump thermostats have an emergency heat setting D. Heat pump thermostats have an automatic change over feature
C
If a fan relay has a defective coil, which of the following is true? A. The normally open contacts will close, but the normally closed contacts will stay closed B. The normally closed contacts will open, but the normally open contacts will stay open C. The normally open contacts will stay open, but the normally closed contacts will stay closed D. The normally closed contacts will open, but the normally open contacts will stay closed
B
If a properly operating, conventional heat pump system is operating in the heating mode with an outside ambient temperature of 30 degrees F, which of the following is the most likely outside ambient temperature? A. -10 degrees F B. 10 degrees F C. 25 degrees F D. 35 degrees F
A
If the coil on the four-way reversing valve fails, A. the heat pump will run in the heating mode when set to the cooling mode B. the heat pump will run in the cooling mode when set to the heating mode C. there will be no ice buildup on the surface of the outdoor coil D. there will be excessive ice buildup on the surface of the indoor coil
D
In package air-to-air heat pumps, supply and return ducts must be insulated to _________________________ A. protect the outdoor coil from excessive temperatures B. prevent heat exchange between the indoor and outdoor coil C. protect the indoor coil from excessive temperatures D. prevent heat exchange between the duct and the ambient air
D
In the emergency heat mode, what percentage of the heat pump system's electric strip heaters will be energized? A. 25% B. 50% C. 75% D. 100%
C
Most heat pump systems are designed to operate in the heating mode when the solenoid is not energized. This is referred to as ________________________. A. cooling situated B. failing in cool mode C. failing in heat mode D. heat situated
A
On a pilot-operated four-way reversing valve, what drives the slide mechanism? A. differential pressure B. solenoid coil C. high pressure D. Electrical current
C
On a split-type heat pump system, the larger field-installed line carries A. high-pressure liquid in the cooling mode and high-pressure gas in the heating mode B. high-pressure gas in the cooling mode and low-pressure gas in the heating mode C. high-pressure gas in the heating mode and low-pressure gas in the cooling mode D. high-pressure liquid in the heating mode and low- pressure gas in the cooling mode
A
On a typically heat-pump split installation for a home, what is the larger copper pipe referred to as? A. gas line B. liquid line C. suction line D. distribution line
B
On ductless split-type heat pump system, which of the following statements is true regarding the field-installed refrigerant lines if the system is operating in the heating mode? A. The larger line will contain low-pressure, low temperature vapor B. The larger line will contain high-pressure, high temperature vapor C. The smaller line will contain high-pressure, high temperature vapor D. The smaller line will contain low-pressure, low temperature vapor
A
One benefit of using scroll compressors instead of reciprocating compressors to increase heat pump system efficiency is that scroll compressors A. do not have "top-of-the-stroke" clearance volume losses B. are lighter than reciprocating compressors C. are cooled by suction gas D. do not require a suction-line accumulator
C
Referring to the heating portion of Figure 43.57, what is the expected suction pressure for an R-410A heat pump system that is operating with a 300 psig discharge pressure if the wet-bulb temperature of the air entering the outdoor coil is 9 degrees F? A. 32 degrees F B. 40 degrees F C. 50 degrees F D. 74 degrees F
A
System overshoot and temperature swing are controlled by a device known as a(n) A. anticipator B. predictor C. regulator D. moderator
A
The coefficient of performance (COP) of electric strip heaters is closest to A. 1:1 B. 2:1 C. 3:1 D. 4:1
A
The component unique to heat-pumps that can control the directional flow of refrigerant A. four way reversing valve B. Defrost control board C. Bi-flow filter dryer D. Bi-flow metering device
C
The defrost cycle on a heat pump system is often terminated by A. a combination of time and temperature B. a combination of temperature and pressure C. either time or temperature D. either temperature or pressure
B
The filter drier that operates as two filter driers in one casing to filter refrigerant flowing in either direction is called the A. bypass filter drier B. biflow filter drier C. counterflow filter drier D. check-type filter drier
A
The isolated port on a reversing valve contains high-pressure A. gas that is entering the valve from the compressor B. gas that is leaving the valve flowing to the compressor C. liquid that is entering the valve from the compressor D. liquid that is leaving the valve flowing to the compressor
A
The main difference between a heat-pump and conventional air conditioning system is? A. How the heat can be moved B. Heat-pump's compressor can operate in either direction C. There is no difference D. Heat-pump's compressor pumps liquid refrigerant
D
The majority of heat pump systems will operate in which mode when the reversing valve's solenoid is deenergized? A. Defrost B. Cooling C. Emergency heat D. Heating
A
The ratio of usable output energy divided by input energy is used to determine system's A. coefficient of performance (COP) B. seasonal energy efficiency ratio (SEER) C. energy efficiency ratio (EER) D. capacity in tons
B
The term "balance point" is best described as A. the point where the heating and cooling capacities of a heat pump system are equal to each other B. the lowest temperature at which a heat pump system can heat a structure without the aid of any supplementary heat C. the lowest temperature at which a heat pump's electric strip heaters can heat a structure D. the point where the heat pump's supplementary heating capacity exactly offsets the system's cooling capacity
A
The term used to describe the outside ambient temperature at which a heat pump can pump in exactly as much heat as the structure is leaking out is ____________________ A. balance point B. thermal point C. set point D. equalization temperature
A
Three factors that are commonly used to initiate the defrost cycle on a heat pump system are time, temperature and A. pressure drop through the outdoor coil B. pressure drop through the indoor coil C. ice thickness on the outdoor coil D. ice thickness on the indoor coil
A
Typically, when control voltage is NOT present at the four-way reversing valve, which mode is it in? A. Heating B. Cooling C. Auxiliary heating mode D. Emergency heating mode
B
What component prevents refrigerant from flowing back into the scroll compressor during its off cycle? A. Service valve B. Check valve C. Accumulator D. Receiver
D
What device is often used in conjunction with a thermostatic expansion valve that allows refrigerant to flow in the opposite direction, bypassing the valve's needle and seat assembly? A. Bypass valve B. Biflow valve C. Counterflow valve D. Check valve
D
What is the approximate percentage of usable heat that remains in outside air when it drops to a temperature of 0 degrees F A. 0% B. 23% C. 57% D. 85%
?
What system conditions are likely to be observed if the heat pump's A-coil is located downstream of the electric heaters? A. High operating pressures B. Low operating pressures C. High suction pressure and low discharge pressure D. Low suction pressure and high discharge pressure
A
When a heat-pump is in the heating mode, in order for heat to be absorbed at the outdoor coil it must be _______________________ than the outdoor ambient air A. colder B. warmer C. same temperature D. higher pressure
False
When a heat-pump is operating with auxiliary heat, it can be said that the heat pump is operating at its balance point True or False
B
When a single metering device is used on a package heat pump system, A. the capillary tube is the most popular choice B. it must be able to adjust refrigerant flow for the heating and cooling modes C. it must be configured to meet the flow requirements for the heating mode D. it must be configured to meet the flow requirements for the cooling mode
C
When an oil-fired or gas-fired furnace is used as a second-stage heat source, A. the furnace will be designed to operate at the same time as the heat pump B. the heat pump will operate only in the defrost mode to remove ice from the coil C. the heat pump will cycle off when the furnace starts to operate D. the furnace will only operate when the system is set to the emergency heat mode
A
When observing the reversing valve, the side that has three piping connections, what component is always connect to the middle pipe? A. Compressor suction B. Compressor discharge C. Thermostatic expansion valve D. Crankcase heater
A
When operating in the heating mode (heat-pump), what actually heats up the indoor air? A. Latent heat of vaporization, and heat of compression B. Latent heat of condensation C. adiabatic cooling D. superheating process
False
When replacing a defective reversing valve, the best tool to use when removing is a hack-saw or reciprocating saw. True or False
D
When servicing a heat pump system, which of the following is true regarding the installation of gauges on the system? A. Gauges should be installed on the system each time the system is serviced B. Only the low-side gauge should be connected to the system during service C. Only the high-side gauge should be connected to the system during service D. Gauges should only be installed on a system if absolutely necessary
C
When the auxiliary heat becomes the primary heating system because of heat pump failure, it is called A. changeover B. thermal balance C. emergency heat D. back up operation
C
When the conditioned space temperature begins to fall due to outdoor conditions, the _____________________ close to initiate a call for heat A. emergency heating contacts B. defrost contacts C. first-stage heating contacts D. second-stage heating contacts
B
Which component of a heat pump is responsible for changing the direction of refrigerant flow through the system? A. Compressor B. Reversing valve C. Check valve D. Metering device
B
Which of the following best describes the operation of second-stage heat on a heat pump system? A. First on, first off B. First on, last off C. Last on, first off D. Last on, last off
B
Which of the following indicates that the reversing valve is not leaking internally? A. Two of the valve's ports are hot, one is cold and on is warm B. Two of the valve's ports are hot and two are cold C. Three of the valve's ports are hot and one is warm D. Three of the valve's ports are cold and one is hot
B
Which of the following is true regarding package-type heat pump systems? A. All field-installed refrigerant lines must be insulated B. They are charged at the factory and bench-tested before they are shipped C. They are shipped with a holding charge of dry nitrogen D. Only larger of the two field-installed refrigerant lines must be insulated
D
Which of the following is true regarding the discharge air temperature of a heat pump system operating in first-stage heating? A. The discharge air temperature is higher than that of an oil-fired heating system, but lower than that of a gas-fired heating system B. The discharge air temperature is higher than that of an gas-fired heating system, but lower than that of a oil-fired heating system C. The discharge air temperature is higher than that of both an oil-fired heating system and gas-fired heating system D. The discharge air temperature is lower than that of both an oil-fired heating system and gas-fired heating system
A
Which of the following metering devices has no moving parts A. Capillary tube B. Piston C. Electronic expansion valve D. Thermostatic expansion valve
A
Which of the following statements is true regarding SEER and HSPF? A. SEER is an efficiency rating for cooling, while HSPF is an efficiency rating for heating B. SEER is an efficiency rating for heating, while HSPF is an efficiency rating for cooling C. Both SEER and HSPF are efficiency ratings for cooling D. Both SEER and HSPF are efficiency ratings for heating
C
Which of the following statements is true regarding heat pump system operation? A. The indoor coil functions as the evaporator in the heating coil B. The outdoor coil functions as the evaporator in the heating coil C. The indoor coil functions as the condenser in the heating coil D. The outdoor coil functions as the condenser in the heating coil
?
Which of the following statements is true regarding the coefficient of performance (COP) of a heat pump system? A. As the compression ratio increases, the efficiency of the system increases B. As the heat of compression (HOC) increases, the efficiency of the system decreases C. As the compression ratio increases, the heat of compression (HOC) decreases D. As the heat of compression decreases, the compression ratio increases
B
Which of the following statements is true regarding the cooling cycle of a heat pump system? A. The compressor cycles on when the thermostat's selector switch is set to the cooling mode and the reversing valve's coil energizes and deenergizes depending on the space temperature B. The coil on the reversing valve is energized when the thermostat's selector switch is set to the cooling mode and the compressor cycles on and off depending on the space temperature C. Both the compressor and the reversing valve's coil are energized when the thermostat's selector switch is set to the cooling mode and the reversing valve's coil energizes and deenergizes depending on the space temperature D. Neither the compressor nor the reversing valve's coil are energized when the thermostat's selector switch is set to the cooling mode, but they are both energized and deenergized depending on the space temperature
B
Why is defrost required on some heat pump systems? A. The outside ambient air is colder than the evaporator coil B. The evaporator coil is colder than the outside ambient air C. The outside ambient air is warmer than the condenser coil D. The evaporator coil is warmer than the air in the occupied space
D
_____________________ filter driers are manufactured to allow refrigerant flow in either direction A. Monoflow B. Suction Line C. Liquid Line D. Biflow
