NATE Exam: AC & HP
a (Centrifugal)correct answerWhich of the following compressors are considered a dynamic
compressor?
a. Centrifugal
b. Reciprocating
d. Rotary
c. Scroll
b (Superheated vapor / sub cooled liquid)correct answerWhat is the condition of the refrigerant as it
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 answerWhich 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 synthetic Polyester POE oil.
Older refrigeration systems using R-12, R-502, and R-22 use a mineral based oil.)correct answerWhich of
the following types of refrigeration oil would you expect to find in a typical commercial R-134a freezer?
a. Mineral 150
b. POE
c. AB
, d. Mineral 300
b (Compressor discharge / compressor suction)correct answerWhere does the small single port tube and
the larger middle port tube go on a typical residential or light commercial reversing valve?
a. Inlet outdoor coil / inlet indoor coil
b. Compressor discharge / compressor suction
c. Compressor suction / compressor discharge
c. Outlet indoor coil / outlet outdoor coil
d (restricted liquid line filter/drier)correct answerIf 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 answerIf 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, 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 answerIf 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 valve
a (Centrifugal)correct answerWhich of the following compressors are considered a dynamic
compressor?
a. Centrifugal
b. Reciprocating
d. Rotary
c. Scroll
b (Superheated vapor / sub cooled liquid)correct answerWhat is the condition of the refrigerant as it
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 answerWhich 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 synthetic Polyester POE oil.
Older refrigeration systems using R-12, R-502, and R-22 use a mineral based oil.)correct answerWhich of
the following types of refrigeration oil would you expect to find in a typical commercial R-134a freezer?
a. Mineral 150
b. POE
c. AB
, d. Mineral 300
b (Compressor discharge / compressor suction)correct answerWhere does the small single port tube and
the larger middle port tube go on a typical residential or light commercial reversing valve?
a. Inlet outdoor coil / inlet indoor coil
b. Compressor discharge / compressor suction
c. Compressor suction / compressor discharge
c. Outlet indoor coil / outlet outdoor coil
d (restricted liquid line filter/drier)correct answerIf 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 answerIf 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, 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 answerIf 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 valve
