NATE AC SERVICE CERTIFICATION
COMPREHENSIVE QUESTIONS AND
SOLUTIONS
◉ High superheat is a symptom of:
A. a system overcharge
B. a clogged air filter
C. a blower fan operating on a speed that is too low
D. an extremely high indoor temperature
Answer: D. An extremely high indoor temperature
◉ Electronic type leak detectors typically have a push-button or
knob for setting a reference refrigerant level. This feature is useful
for:
A. adjusting the detector after installing a new battery
B. checking the factory calibration of the instrument
C. setting the detector for use in environments with ambient
refrigerant vapor
D. adjusting the detector for the type of refrigerant to be checked
Answer: C. Setting the detector for use in environments with
ambient refrigerant vapor
,◉ The continuity of a fuse should be tested by:
A. checking resistance with power off
B. checking resistance with power on
C. checking resistance from the load side of the fuse to ground
D. checking resistance from the supply side of the fuse to ground
Answer: A. Checking resistance with power off
◉ When performing a preventive maintenance on an outdoor
unit, check the wiring to be certain:
A. no wires have broken or loosened
B. all wires are connected to their proper terminal
C. all wire sizes are correct
D. the correct wire type has been used
Answer: A. No wires have broken or loosened
◉ What is the effect of 170 volts supplied to a 208/230 volt
compressor?
A. no effect; the motor will continue to run
B. current decreases and the motor runs cooler
C. current increases and the motor may trip on overload
, D. current increases and the motor runs cooler
Answer: C. Current increases and the motor may trip on overload
◉ To properly set the heat anticipator it is necessary to check the:
A. voltage rating of the heat relay
B. heating control circuit amperage draw
C. BTU output of the furnace
D. VA rating of the transformer
Answer: B. Heating control circuit amperage draw
◉ What could cause a customer to complain that their home feels
damp or "sticky"?
A. high head pressure
B. returns may be pulling in attic air due to duct damage
C. the thermostat setting is too low
D. the heat sequencers may be off
Answer: B. Returns may be pulling in attic air due to duct damage
◉ In a simple refrigeration system, the refrigerant boils in the:
A. metering device
B. compressor
COMPREHENSIVE QUESTIONS AND
SOLUTIONS
◉ High superheat is a symptom of:
A. a system overcharge
B. a clogged air filter
C. a blower fan operating on a speed that is too low
D. an extremely high indoor temperature
Answer: D. An extremely high indoor temperature
◉ Electronic type leak detectors typically have a push-button or
knob for setting a reference refrigerant level. This feature is useful
for:
A. adjusting the detector after installing a new battery
B. checking the factory calibration of the instrument
C. setting the detector for use in environments with ambient
refrigerant vapor
D. adjusting the detector for the type of refrigerant to be checked
Answer: C. Setting the detector for use in environments with
ambient refrigerant vapor
,◉ The continuity of a fuse should be tested by:
A. checking resistance with power off
B. checking resistance with power on
C. checking resistance from the load side of the fuse to ground
D. checking resistance from the supply side of the fuse to ground
Answer: A. Checking resistance with power off
◉ When performing a preventive maintenance on an outdoor
unit, check the wiring to be certain:
A. no wires have broken or loosened
B. all wires are connected to their proper terminal
C. all wire sizes are correct
D. the correct wire type has been used
Answer: A. No wires have broken or loosened
◉ What is the effect of 170 volts supplied to a 208/230 volt
compressor?
A. no effect; the motor will continue to run
B. current decreases and the motor runs cooler
C. current increases and the motor may trip on overload
, D. current increases and the motor runs cooler
Answer: C. Current increases and the motor may trip on overload
◉ To properly set the heat anticipator it is necessary to check the:
A. voltage rating of the heat relay
B. heating control circuit amperage draw
C. BTU output of the furnace
D. VA rating of the transformer
Answer: B. Heating control circuit amperage draw
◉ What could cause a customer to complain that their home feels
damp or "sticky"?
A. high head pressure
B. returns may be pulling in attic air due to duct damage
C. the thermostat setting is too low
D. the heat sequencers may be off
Answer: B. Returns may be pulling in attic air due to duct damage
◉ In a simple refrigeration system, the refrigerant boils in the:
A. metering device
B. compressor
