NATE Exam: AC & HP
a (Centrifugal) correct answers Which of the following compressors are
considered a
dynamic
compressor?
a.
Centrifugal
b.
Reciprocating
d.
Rotary
c.
Scroll
b (Superheated vapor / sub cooled liquid) correct answers What is the
condition ofas
refrigerant theit enters and leaves the condensing coil of a typical light
commercial
HVAC
system?
a. Vapor /
liquid
b. Superheated vapor / sub cooled
liquid
c. Saturated vapor / saturated
liquid
d. Hot gas / cool
liquid
b (Thermal expansion valve) correct answers Which one of the
following are
considered the best metering device of the
industry?
a. Capillary
tube
b. Thermal expansion
valve
d. Constant pressure expansion
valve
c. Electronic expansion
valve
b (POE. Newer refrigerant systems today using R-134a and R-410a use a
Polyester POE oil. Older refrigeration systems using R-12, R-502, and R-
synthetic
22 use abased oil.) correct answers Which of the following types of
mineral
refrigeration
would oil to find in a typical commercial R-134a
you expect
freezer?
a. Mineral
150
b. POE
c.
AB
d. Mineral
300
b (Compressor discharge / compressor suction) correct answers Where does
the small
single port tube and the larger middle port tube go on a typical
residential orreversing
commercial light
valve?
a. Inlet outdoor coil / inlet
indoor
b. coil
Compressor discharge / compressor
suction
c. Compressor suction / compressor
discharge
, c. Outlet indoor coil / outlet
outdoor coil
d (restricted liquid line filter/drier) correct answers If you were working on a
3.5 ton split
system, with a 125,000 BTH/H horizontal furnace, and you had a low suction
pressure,
low discharge pressure, high superheat, and high subcooling, what is
wrong with the
system
?
a. low refrigerant
charge
b. overcharged
system
c. overfeeding metering
device
d. restricted liquid line
filter/drier
c (overfeeding metering device) correct answers If you were working on a t
3.5 ton spli
system, with a 125,000 BTU/H horizontal furnace, and you had high suction
pressure,
low discharge pressure, low superheat, and low subcooling, what is
wrong with the
system
?
a. low refrigerant
charge
b. overcharged
system
c. overfeeding metering
device
d. restricted liquid line
filter/drier
a (weak compressor valves) correct answers If you were working on a
3.5 ton split
system, with a 125,000 BTU/H horizontal furnace, and you had high suction
pressure,
low discharge pressure, high superheat, and low subcooling, what is
wrong with the
system
?
a. weak compressor
valves
b. stuck reversing
valve
c. bad indoor check
d. bad outdoor check
valve
valve
b (overcharge system) correct answers If you were working on a 3.5 ton
split system,
with a 125,000 BTU/H horizontal furnace, and you had high suction
pressure, high
discharge pressure, low superheat, and high subcooling, what is
wrong with the
system
?
a. low refrigerant
charge
b. overcharged
system
c. overfeeding metering
device
d. restricted liquid line
filter/drier
d (to compensate charge in the cooling cycle) correct answers You are
working
heat pump
on package
a unit and come across a charge compensator, what is it
used for?
a. to compensate for a low refrigerant
charge
a (Centrifugal) correct answers Which of the following compressors are
considered a
dynamic
compressor?
a.
Centrifugal
b.
Reciprocating
d.
Rotary
c.
Scroll
b (Superheated vapor / sub cooled liquid) correct answers What is the
condition ofas
refrigerant theit enters and leaves the condensing coil of a typical light
commercial
HVAC
system?
a. Vapor /
liquid
b. Superheated vapor / sub cooled
liquid
c. Saturated vapor / saturated
liquid
d. Hot gas / cool
liquid
b (Thermal expansion valve) correct answers Which one of the
following are
considered the best metering device of the
industry?
a. Capillary
tube
b. Thermal expansion
valve
d. Constant pressure expansion
valve
c. Electronic expansion
valve
b (POE. Newer refrigerant systems today using R-134a and R-410a use a
Polyester POE oil. Older refrigeration systems using R-12, R-502, and R-
synthetic
22 use abased oil.) correct answers Which of the following types of
mineral
refrigeration
would oil to find in a typical commercial R-134a
you expect
freezer?
a. Mineral
150
b. POE
c.
AB
d. Mineral
300
b (Compressor discharge / compressor suction) correct answers Where does
the small
single port tube and the larger middle port tube go on a typical
residential orreversing
commercial light
valve?
a. Inlet outdoor coil / inlet
indoor
b. coil
Compressor discharge / compressor
suction
c. Compressor suction / compressor
discharge
, c. Outlet indoor coil / outlet
outdoor coil
d (restricted liquid line filter/drier) correct answers If you were working on a
3.5 ton split
system, with a 125,000 BTH/H horizontal furnace, and you had a low suction
pressure,
low discharge pressure, high superheat, and high subcooling, what is
wrong with the
system
?
a. low refrigerant
charge
b. overcharged
system
c. overfeeding metering
device
d. restricted liquid line
filter/drier
c (overfeeding metering device) correct answers If you were working on a t
3.5 ton spli
system, with a 125,000 BTU/H horizontal furnace, and you had high suction
pressure,
low discharge pressure, low superheat, and low subcooling, what is
wrong with the
system
?
a. low refrigerant
charge
b. overcharged
system
c. overfeeding metering
device
d. restricted liquid line
filter/drier
a (weak compressor valves) correct answers If you were working on a
3.5 ton split
system, with a 125,000 BTU/H horizontal furnace, and you had high suction
pressure,
low discharge pressure, high superheat, and low subcooling, what is
wrong with the
system
?
a. weak compressor
valves
b. stuck reversing
valve
c. bad indoor check
d. bad outdoor check
valve
valve
b (overcharge system) correct answers If you were working on a 3.5 ton
split system,
with a 125,000 BTU/H horizontal furnace, and you had high suction
pressure, high
discharge pressure, low superheat, and high subcooling, what is
wrong with the
system
?
a. low refrigerant
charge
b. overcharged
system
c. overfeeding metering
device
d. restricted liquid line
filter/drier
d (to compensate charge in the cooling cycle) correct answers You are
working
heat pump
on package
a unit and come across a charge compensator, what is it
used for?
a. to compensate for a low refrigerant
charge
