NATE A/C Exam #1 Latest Updated
Graded A+
A 3ton residential split system should move about how many CFM total?
A: 800 CFM
B: 1000 CFM
C: 1200 CFM
D: 1500 CFM - ANSWER-C: 1200 CFM
Rule of thumb, tonnage x 400 = cfm; 3 x 400 = 1,200cfm
A compressor is short cycling. Which of the following would not be the cause?
A: Low pressure controller differential set too close
B: Automatic reset high pressure control differential set too close
C: Low refrigerant charge
D: Leaking compressor suction valve - ANSWER-D: Leaking compressor suction valve
A double suction riser is used to
A: Help improve refrigerant return
B: Allow the compressor to pump at a greater capacity
C: Decrease suction line resistance
D: Improve oil return as system capacity changes - ANSWER-D: Improve oil return as
system capacity changes
A fully hermetic compressor on a 3 ton residential split system has three electrical
terminals on the side of the compressor. An ohmmeter reads the following: terminal A to
B = 20 ohms, A to C = 15 ohms and B to C = 5 ohms. There was a reading of infinity
between all three terminals to ground. Which terminal is the common terminal?
A: Terminal A is common
, B: Terminal B is common
C: Terminal C is common
D: There is no common terminal on this type compressor - ANSWER-C: Terminal C is
common
To determine the common terminal, find the to terminals with the highest reading. The
terminal left over is the common terminal. Put the probe on the common terminal and
either of the other two terminals, highest reading is the Start terminal, and the other is
the run terminal.
A grille equipped with a damper control is called
A: A vane
B: A register
C: A louver
D: A damper - ANSWER-B: A register
A hot liquid line with a low to normal high side pressure is an indication of
A: An overcharged system
B: An undercharged system
C: Air in the system
D: A restricted filterdrier - ANSWER-B: An undercharged system
A hot wood stove gives up heat to the room by
A: Conduction
B: Convection
C: Radiation
D: All three at the same time - ANSWER-D: All three at the same time
A lockout relay can be reset by
A: De-energizing the main power
Graded A+
A 3ton residential split system should move about how many CFM total?
A: 800 CFM
B: 1000 CFM
C: 1200 CFM
D: 1500 CFM - ANSWER-C: 1200 CFM
Rule of thumb, tonnage x 400 = cfm; 3 x 400 = 1,200cfm
A compressor is short cycling. Which of the following would not be the cause?
A: Low pressure controller differential set too close
B: Automatic reset high pressure control differential set too close
C: Low refrigerant charge
D: Leaking compressor suction valve - ANSWER-D: Leaking compressor suction valve
A double suction riser is used to
A: Help improve refrigerant return
B: Allow the compressor to pump at a greater capacity
C: Decrease suction line resistance
D: Improve oil return as system capacity changes - ANSWER-D: Improve oil return as
system capacity changes
A fully hermetic compressor on a 3 ton residential split system has three electrical
terminals on the side of the compressor. An ohmmeter reads the following: terminal A to
B = 20 ohms, A to C = 15 ohms and B to C = 5 ohms. There was a reading of infinity
between all three terminals to ground. Which terminal is the common terminal?
A: Terminal A is common
, B: Terminal B is common
C: Terminal C is common
D: There is no common terminal on this type compressor - ANSWER-C: Terminal C is
common
To determine the common terminal, find the to terminals with the highest reading. The
terminal left over is the common terminal. Put the probe on the common terminal and
either of the other two terminals, highest reading is the Start terminal, and the other is
the run terminal.
A grille equipped with a damper control is called
A: A vane
B: A register
C: A louver
D: A damper - ANSWER-B: A register
A hot liquid line with a low to normal high side pressure is an indication of
A: An overcharged system
B: An undercharged system
C: Air in the system
D: A restricted filterdrier - ANSWER-B: An undercharged system
A hot wood stove gives up heat to the room by
A: Conduction
B: Convection
C: Radiation
D: All three at the same time - ANSWER-D: All three at the same time
A lockout relay can be reset by
A: De-energizing the main power
