NATE Heat Pump Retail 2024 - Questions with Correct
Answers
1. R-22 Vapor Line Specifications:
Vapor pressure drop should not exceed 6-7 psi or 6°F for proper line diameters and
lengths.
2. Soldering Copper or Brass Parts:
The primary purpose of using flux is to prevent oxidation.
3. Defrost Cycle Runoff:
Water runoff from a defrost cycle must drain off and away from the outdoor coil to
prevent excessive ice buildup and reduce capacity.
4. Curb Gasket Function:
The curb gasket helps reduce sound transmission and prevents water leaks in packaged
heat pump installations on rooftops.
5. Control for Fossil Fuel Furnace and Heat Pump:
When installing a heat pump on an existing fossil fuel furnace, a control is required to
ensure that both systems do not operate simultaneously during normal heating.
6. Hermetic Refrigeration Compressor Protection:
A compressor’s motor windings could be damaged if energized while the system is
under a deep vacuum.
7. Evacuation Completeness:
To consider evacuation complete, the refrigerant circuit must be evacuated to 500
microns or below.
8. Factory Supplied Charge:
A system typically comes with a charge sufficient for a 15-foot line set.
, 9. Adjusting Refrigerant Charge:
For a 25-foot line set with a 3/8-inch liquid line, the refrigerant charge should be
adjusted by 0.6 ounces per foot of added refrigerant line length, totaling 6 pounds of
refrigerant.
10. Duct Drive Slips:
Drive slips are commonly installed on the shorter sides of rectangular ductwork.
11. Setting Heat Anticipators:
To set a heat anticipator, check the amperage draw of the heating control circuit.
12. Coil TD in Heat Pumps:
In normal, ice-free conditions, a heat pump maintains a temperature difference (TD)
between the outdoor coil and the ambient temperature.
13. Leak Detection Sensitivity:
An electronic leak detector should detect leaks as small as 0.05 oz per year.
14. Manifold Gauge Set Operation:
Refrigerant oil in the hose does not affect the gauge reading.
15. Pressure Conversion:
At sea level, 35 psig equals 49.7 psia.
16. Furnace CFM Calculation:
If a furnace has 100,000 Btu output with 65°F return air and 135°F supply air, the
required CFM is 1323.
17. Noisy Diffuser Maintenance:
A noisy diffuser with a loose vane is best serviced by replacing it.
18. Outdoor Fan Check:
Ensure the outdoor fan runs freely with no binding during preventive maintenance.
19. Voltage Issue with Compressor:
Answers
1. R-22 Vapor Line Specifications:
Vapor pressure drop should not exceed 6-7 psi or 6°F for proper line diameters and
lengths.
2. Soldering Copper or Brass Parts:
The primary purpose of using flux is to prevent oxidation.
3. Defrost Cycle Runoff:
Water runoff from a defrost cycle must drain off and away from the outdoor coil to
prevent excessive ice buildup and reduce capacity.
4. Curb Gasket Function:
The curb gasket helps reduce sound transmission and prevents water leaks in packaged
heat pump installations on rooftops.
5. Control for Fossil Fuel Furnace and Heat Pump:
When installing a heat pump on an existing fossil fuel furnace, a control is required to
ensure that both systems do not operate simultaneously during normal heating.
6. Hermetic Refrigeration Compressor Protection:
A compressor’s motor windings could be damaged if energized while the system is
under a deep vacuum.
7. Evacuation Completeness:
To consider evacuation complete, the refrigerant circuit must be evacuated to 500
microns or below.
8. Factory Supplied Charge:
A system typically comes with a charge sufficient for a 15-foot line set.
, 9. Adjusting Refrigerant Charge:
For a 25-foot line set with a 3/8-inch liquid line, the refrigerant charge should be
adjusted by 0.6 ounces per foot of added refrigerant line length, totaling 6 pounds of
refrigerant.
10. Duct Drive Slips:
Drive slips are commonly installed on the shorter sides of rectangular ductwork.
11. Setting Heat Anticipators:
To set a heat anticipator, check the amperage draw of the heating control circuit.
12. Coil TD in Heat Pumps:
In normal, ice-free conditions, a heat pump maintains a temperature difference (TD)
between the outdoor coil and the ambient temperature.
13. Leak Detection Sensitivity:
An electronic leak detector should detect leaks as small as 0.05 oz per year.
14. Manifold Gauge Set Operation:
Refrigerant oil in the hose does not affect the gauge reading.
15. Pressure Conversion:
At sea level, 35 psig equals 49.7 psia.
16. Furnace CFM Calculation:
If a furnace has 100,000 Btu output with 65°F return air and 135°F supply air, the
required CFM is 1323.
17. Noisy Diffuser Maintenance:
A noisy diffuser with a loose vane is best serviced by replacing it.
18. Outdoor Fan Check:
Ensure the outdoor fan runs freely with no binding during preventive maintenance.
19. Voltage Issue with Compressor:
