Core Exam 100 Questions And Answers
With Verified Solutions Well Illustrated!!!
With an R-410A condensing pressure of 395 psig and a liquid line temperature of
108 degree F, what is the subcooling temperature?
A. 36°F
B. 24°F
C. 16°F
D. 8°F - ANSWER✔✔ D. 8°F
When performing maintenance on a heat pump, the technician should check the
outdoor fan to be certain:
A. that fan torque meets manufacturer specifications
B. to verify proper RPM
C. the fan runs freely without binding or vibrations
D. to check the condenser motor nameplate for correct voltage - ANSWER✔✔ C.
the fan runs freely without binding or vibrations
The continuity of a fuse used in a disconnect should be tested by checking
resistance:
A. with power off
B. with power on
C. from the load side of the fuse to ground
D. from the supply side of the fuse to ground - ANSWER✔✔ A. with power off
Why does the outdoor fan on a heat pump stop during defrost?
A. Decreased high side pressure
,B. Decreased low side pressure
C. Minimize defrost time
D. Increase defrost time - ANSWER✔✔ C. Minimize defrost time
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. What is the SCFM
(standard CFM)?
A. 689 SCFM
B. 1323 SCFM
C. 1425 SCFM
D. 1538 SCFM - ANSWER✔✔ B. 1323 SCFM
The following measurements are recorded on an operating heat pump system. The
heat pump is operating with the compressor only with no auxiliary heat
*Heat pump only supply air temperature 92°F
*Heat pump only return air temperature 70°F
*Outdoor temperature 54°F
*Supply air temp./auxiliary heat ON 115°F
*Return air temp./auxiliary heat ON 70°F
*CFM 1228
What is the heating capacity of the unit in Btu/h?
A. 39,787 Btu/h
B. 30,612 Btu/h
C. 21,219 Btu/h
D. 29,177 Btu/h - ANSWER✔✔ D. 29,177 Btu/h
, R-410A vapor line diameters with lengths 50 feet or less are typically specified for
a vapor pressure drop that does not exceed what value?
A. Less than 1 psi
B. 3 psi
C. 5 psi
D. 7 psi - ANSWER✔✔ C. 5 psi
Which of the following is used to make accurate residential loan calculations?
A. ACCA Manual D
B. ACCA Manual J
C. International Mechanical Code
D. NFPA 54 - ANSWER✔✔ B. ACCA Manual J
The following conditions exist in a circuit that supplies power to three parallel
loads:
*One load is resistive,
*One load is capacitive,
*One load is inductive
The total current in the circuit when operating will be:
A. the resistive current plus the inductive current minus the capacitive current
B. the resistive current alone since the inductive e current will always be cancelled
by the capacitive current
C. the average of the currents flowing through each load
D. the sum of the currents through each load - ANSWER✔✔ D. the sum of the
currents through each load
With Verified Solutions Well Illustrated!!!
With an R-410A condensing pressure of 395 psig and a liquid line temperature of
108 degree F, what is the subcooling temperature?
A. 36°F
B. 24°F
C. 16°F
D. 8°F - ANSWER✔✔ D. 8°F
When performing maintenance on a heat pump, the technician should check the
outdoor fan to be certain:
A. that fan torque meets manufacturer specifications
B. to verify proper RPM
C. the fan runs freely without binding or vibrations
D. to check the condenser motor nameplate for correct voltage - ANSWER✔✔ C.
the fan runs freely without binding or vibrations
The continuity of a fuse used in a disconnect should be tested by checking
resistance:
A. with power off
B. with power on
C. from the load side of the fuse to ground
D. from the supply side of the fuse to ground - ANSWER✔✔ A. with power off
Why does the outdoor fan on a heat pump stop during defrost?
A. Decreased high side pressure
,B. Decreased low side pressure
C. Minimize defrost time
D. Increase defrost time - ANSWER✔✔ C. Minimize defrost time
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. What is the SCFM
(standard CFM)?
A. 689 SCFM
B. 1323 SCFM
C. 1425 SCFM
D. 1538 SCFM - ANSWER✔✔ B. 1323 SCFM
The following measurements are recorded on an operating heat pump system. The
heat pump is operating with the compressor only with no auxiliary heat
*Heat pump only supply air temperature 92°F
*Heat pump only return air temperature 70°F
*Outdoor temperature 54°F
*Supply air temp./auxiliary heat ON 115°F
*Return air temp./auxiliary heat ON 70°F
*CFM 1228
What is the heating capacity of the unit in Btu/h?
A. 39,787 Btu/h
B. 30,612 Btu/h
C. 21,219 Btu/h
D. 29,177 Btu/h - ANSWER✔✔ D. 29,177 Btu/h
, R-410A vapor line diameters with lengths 50 feet or less are typically specified for
a vapor pressure drop that does not exceed what value?
A. Less than 1 psi
B. 3 psi
C. 5 psi
D. 7 psi - ANSWER✔✔ C. 5 psi
Which of the following is used to make accurate residential loan calculations?
A. ACCA Manual D
B. ACCA Manual J
C. International Mechanical Code
D. NFPA 54 - ANSWER✔✔ B. ACCA Manual J
The following conditions exist in a circuit that supplies power to three parallel
loads:
*One load is resistive,
*One load is capacitive,
*One load is inductive
The total current in the circuit when operating will be:
A. the resistive current plus the inductive current minus the capacitive current
B. the resistive current alone since the inductive e current will always be cancelled
by the capacitive current
C. the average of the currents flowing through each load
D. the sum of the currents through each load - ANSWER✔✔ D. the sum of the
currents through each load
