NATE heat pump 109 Questions with
Correct Answers
R-22 vapor line diameters and lengths are typically specified for a vapor pressure drop
that does not exceed - Answer6-7 psi or 6 degress F
The primary purpose of using flux when soldering copper or brass parts is to prevent -
AnswerOxidation
The water that results from a defrost cycle of an air to air heat pump (runoff) must drain
off and away from the outdoor coil to prevent - AnswerExcessive ice build up
The component used to reduce sound transmission and prevent water leaks of a
packaged heat pump installed on a roof is the - AnswerCurb gasket
When under a deep vacuum, a hermetic refrigeration compressor's motor windings
could be ________ if energized - AnswerDamaged
In order for an evacuation to be considered complete, a heat pump refrigerant circuit
should be evacuated to a vacuum pressure of - Answer500 microns or below
A system is supplied from the factory with charge for a 15 foot line set. The data plate
shows the required system charge to be 5 pounds 10 ounces. The line set uses a 3/8
inch liquid line and is 25 feet long. The manufacturer's instruction sheet specifies 0.6
ounces of refrigerant to be added for each added foot of refrigerant line length so the
total refrigerant charge for the system would be - Answer6 lbs(25-15=10 10x0.6=6oz
6oz+5lbs 10oz= 5lbs 16oz the equilvalent of 6lbs)
Drive slips are typically installed on the __________ sides of rectangular ducts -
AnswerShorter
To properly set a heat anticipator it is necessary to check the - Answerheating control
circuit amperage draw
A heat pump operating in normal ice free conditions maintains a certain temperature
difference between the outdoor coil temperature and the surrounding outdoor ambient.
This temperature difference is referred to as - AnswerCoil TD (temperature difference)
The smallest refrigerant leak that an electronic leak detector should be capable of
sensing is - Answer0.05 oz. per year
, When checking the pressures in an operating system with a manifold gauge set,
refrigerant oil in a hose will have ___ ______ on the gauge reading - AnswerNo effect
At sea level, a gauge pressure of 35 psig is equal to an absolute pressure of -
Answer49.7 psia
A technician measures the return air temperature of a 100,000 Btu output furnace to be
65°F and the supply side air temperature is 135°F. The CFM would be - Answer1323
(TD= 135-65=70➡️100,000/TDx1.08 ➡️100,000/75.6=1323)
A residential supply diffuser that is noisy because of a loose vane is best serviced by -
AnswerReplacing the diffuser
When performing preventive maintenance on a heat pump the technician should check
the outdoor fan to be certain that the fan - Answerruns freely with no binding
What is the effect of 170 volts supplied to a 208/230 volt compressor would cause a
current - Answerincrease and the motor may trip on overload
On a service call for a cooling problem with a heat pump, your inspections find a liquid
line that has condensation on it. The most likely cause would be the - Answerliquid
line is restricted
A reason for cool air complaints when a heat pump is operating in the heating cycle is -
Answerexcessive supply air velocities
A dirty or clogged air filter in an operating heat pump system can cause -
Answerinadequate heating
To minimize noise problems in residential duct systems, the range (recommended to
maximum) of design air velocity in the rectangular main supply trunk is - Answer700
to 900 fpm
The effect of adding a charge to sub cooling is - Answerit increases it
When a capillary tube is overcharged you would get a ____ superheat and ____ sub
cooling - AnswerLow,high
The effect of a low charge on the switchover operations of a reversing valve is -
Answerthe reversing valves are less likely to transfer
A technician is working on a heat pump with a capacitor start-capacitor run compressor.
On initial startup, the compressor hums momentarily and the shuts down on internal
overload, the problem is - Answertoo great a pressure difference on the compressor
Correct Answers
R-22 vapor line diameters and lengths are typically specified for a vapor pressure drop
that does not exceed - Answer6-7 psi or 6 degress F
The primary purpose of using flux when soldering copper or brass parts is to prevent -
AnswerOxidation
The water that results from a defrost cycle of an air to air heat pump (runoff) must drain
off and away from the outdoor coil to prevent - AnswerExcessive ice build up
The component used to reduce sound transmission and prevent water leaks of a
packaged heat pump installed on a roof is the - AnswerCurb gasket
When under a deep vacuum, a hermetic refrigeration compressor's motor windings
could be ________ if energized - AnswerDamaged
In order for an evacuation to be considered complete, a heat pump refrigerant circuit
should be evacuated to a vacuum pressure of - Answer500 microns or below
A system is supplied from the factory with charge for a 15 foot line set. The data plate
shows the required system charge to be 5 pounds 10 ounces. The line set uses a 3/8
inch liquid line and is 25 feet long. The manufacturer's instruction sheet specifies 0.6
ounces of refrigerant to be added for each added foot of refrigerant line length so the
total refrigerant charge for the system would be - Answer6 lbs(25-15=10 10x0.6=6oz
6oz+5lbs 10oz= 5lbs 16oz the equilvalent of 6lbs)
Drive slips are typically installed on the __________ sides of rectangular ducts -
AnswerShorter
To properly set a heat anticipator it is necessary to check the - Answerheating control
circuit amperage draw
A heat pump operating in normal ice free conditions maintains a certain temperature
difference between the outdoor coil temperature and the surrounding outdoor ambient.
This temperature difference is referred to as - AnswerCoil TD (temperature difference)
The smallest refrigerant leak that an electronic leak detector should be capable of
sensing is - Answer0.05 oz. per year
, When checking the pressures in an operating system with a manifold gauge set,
refrigerant oil in a hose will have ___ ______ on the gauge reading - AnswerNo effect
At sea level, a gauge pressure of 35 psig is equal to an absolute pressure of -
Answer49.7 psia
A technician measures the return air temperature of a 100,000 Btu output furnace to be
65°F and the supply side air temperature is 135°F. The CFM would be - Answer1323
(TD= 135-65=70➡️100,000/TDx1.08 ➡️100,000/75.6=1323)
A residential supply diffuser that is noisy because of a loose vane is best serviced by -
AnswerReplacing the diffuser
When performing preventive maintenance on a heat pump the technician should check
the outdoor fan to be certain that the fan - Answerruns freely with no binding
What is the effect of 170 volts supplied to a 208/230 volt compressor would cause a
current - Answerincrease and the motor may trip on overload
On a service call for a cooling problem with a heat pump, your inspections find a liquid
line that has condensation on it. The most likely cause would be the - Answerliquid
line is restricted
A reason for cool air complaints when a heat pump is operating in the heating cycle is -
Answerexcessive supply air velocities
A dirty or clogged air filter in an operating heat pump system can cause -
Answerinadequate heating
To minimize noise problems in residential duct systems, the range (recommended to
maximum) of design air velocity in the rectangular main supply trunk is - Answer700
to 900 fpm
The effect of adding a charge to sub cooling is - Answerit increases it
When a capillary tube is overcharged you would get a ____ superheat and ____ sub
cooling - AnswerLow,high
The effect of a low charge on the switchover operations of a reversing valve is -
Answerthe reversing valves are less likely to transfer
A technician is working on a heat pump with a capacitor start-capacitor run compressor.
On initial startup, the compressor hums momentarily and the shuts down on internal
overload, the problem is - Answertoo great a pressure difference on the compressor
