NATE Heat Pump Questions and Answers
1.R-22 vapor line diameters and lengths are typically
specified for a vapor pressure drop that does not exceed
ANS 6-7 psi or 6 degress F
2.The primary purpose of using flux when soldering copper or
brass parts is to prevent
ANS Oxidation
3.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
ANS Excessive ice build up
4.The component used to reduce sound transmission and
prevent water leaks of a packaged heat pump installed on a
roof is the
ANS Curb gasket
5.When under a deep vacuum, a hermetic refrigeration
compressor's motor windings could be if energized
ANS Damaged
6.In order for an evacuation to be considered complete, a heat
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20
,pump refriger- ant circuit should be evacuated to a vacuum
pressure of
ANS 500 microns or below
7.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
ANS 6 lbs(25-15=10 10x0.6=6oz 6oz+5lbs 10oz= 5lbs 16oz the
equilvalent of 6lbs)
8.Drive slips are typically installed on the sides of
rectangular ducts
ANS Shorter
9.To properly set a heat anticipator it is necessary to check the
ANS heating control circuit amperage draw
10.A heat pump operating in normal ice free conditions
maintains a certain temperature difference between the
outdoor coil temperature and the sur- rounding outdoor
ambient. This temperature difference is referred to as
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20
, ANS Coil TD (temperature difference)
11.The smallest refrigerant leak that an electronic leak
detector should be capable of sensing is
ANS 0.05 oz. per year
12.When checking the pressures in an operating system with a
manifold gauge set, refrigerant oil in a hose will have on
the gauge reading-
ANS No effect
13.At sea level, a gauge pressure of 35 psig is equal to an
absolute pressure of
ANS 49.7 psia
14.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
ANS 1323 (TD= 135-65=701¡ 00,000/TDx1.08 1¡ 00,000/75.6=1323)
15.A residential supply diffuser that is noisy because of a loose
vane is best serviced by
ANS Replacing the diffuser
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20
1.R-22 vapor line diameters and lengths are typically
specified for a vapor pressure drop that does not exceed
ANS 6-7 psi or 6 degress F
2.The primary purpose of using flux when soldering copper or
brass parts is to prevent
ANS Oxidation
3.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
ANS Excessive ice build up
4.The component used to reduce sound transmission and
prevent water leaks of a packaged heat pump installed on a
roof is the
ANS Curb gasket
5.When under a deep vacuum, a hermetic refrigeration
compressor's motor windings could be if energized
ANS Damaged
6.In order for an evacuation to be considered complete, a heat
1/
20
,pump refriger- ant circuit should be evacuated to a vacuum
pressure of
ANS 500 microns or below
7.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
ANS 6 lbs(25-15=10 10x0.6=6oz 6oz+5lbs 10oz= 5lbs 16oz the
equilvalent of 6lbs)
8.Drive slips are typically installed on the sides of
rectangular ducts
ANS Shorter
9.To properly set a heat anticipator it is necessary to check the
ANS heating control circuit amperage draw
10.A heat pump operating in normal ice free conditions
maintains a certain temperature difference between the
outdoor coil temperature and the sur- rounding outdoor
ambient. This temperature difference is referred to as
2/
20
, ANS Coil TD (temperature difference)
11.The smallest refrigerant leak that an electronic leak
detector should be capable of sensing is
ANS 0.05 oz. per year
12.When checking the pressures in an operating system with a
manifold gauge set, refrigerant oil in a hose will have on
the gauge reading-
ANS No effect
13.At sea level, a gauge pressure of 35 psig is equal to an
absolute pressure of
ANS 49.7 psia
14.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
ANS 1323 (TD= 135-65=701¡ 00,000/TDx1.08 1¡ 00,000/75.6=1323)
15.A residential supply diffuser that is noisy because of a loose
vane is best serviced by
ANS Replacing the diffuser
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20
