HVAC NATE HEAT PUMP QUESTIONS &
ANSWERS 100% SOLVED
On an R-22 system, line diameters and lengths are typically specified for a vapor
pressure drop that does not exceed what? - ANSWER6-7PSI or 6F
What is the primary purpose of using flux when soldering copper or brass parts? -
ANSWERPrevent Oxidation
What are the three things that happen when a heat pump is cycled into the defrost
mode? - ANSWERReversing valve switches to cooling mode, Outdoor fan is shut off,
and auxiliary heat is energized.
What is a duct system that has a single trunk extending in one or two directions with
many branch ducts? - ANSWERExtended Plenum Duct System
What is the effect on supply airflow when static pressure on the return is reduced? -
ANSWERAirflow will be increased.
What is the voltage most often used to power the outdoor unit in a residential system? -
ANSWER240V Single Phase
What happens if you increased suction pressure on a reciprocating compressor? -
ANSWERThe capacity would decrease.
The refrigerants typically used in residential and light commercial pumps have a storage
life of? - ANSWERAn indefinite length of time.
A restricted drier can cause what? - ANSWERLower than normal suction pressure
What blower motor type is generally used on air handling equipment with capacities of
4,000 cfm or greater? - ANSWERBelt driven with three phases.
Electronic air cleaners can operate with internal voltages as high as? - ANSWER5000V
A system is supplied from the factory with charge for a 15 foot line set. The data plate
shows the required system charge to be 5 pounds 10 ounces. The line set uses a 3/8
inch liquid line and is 25 feet long. The manufacturer's instruction sheet specifies 0.6
ounces of refrigerant to be added for each added foot of refrigerant line length. How
much refrigerant is needed to completely charge the system? - ANSWER6lbs
, Where are drive slips typically installed? - ANSWEROn the shorter sides of rectangular
duct.
What is a necessary check to properly set a heat anticipator? - ANSWERHeating
control circuit amperage
draw.
A heat pump operating in normal ice free conditions maintains a certain temperature
difference between the outdoor coil temperature and the surrounding outdoor ambient.
What is this temperature referred to as? - ANSWERCoil TD.
What is the smallest refrigerant leak that an electronic leak detector should be capable
of sensing? - ANSWER.o5oz per year.
When checking the pressures in an operating system with a manifold gauge set, will
refrigerant oil in a hose will have an effect on the gauge? - ANSWERNo
What is the absolute pressure at sea level if a gauge pressure is 35 psig? -
ANSWER49.7psia
100,000 BTUH output furnace.
Return air temp is 65F.
Supply air is 135F.
What is the CFM? - ANSWER1323CFM
What is the best method of repair when a residential supply diffuser is noisy because of
a loose vane? - ANSWERReplace the diffuser.
When performing preventive maintenance on a heat pump what should the technician
check and why? - ANSWEROutdoor fan. To be certain it runs freely with no binding.
What is the effect of 170 volts supplied to a 208/230 volt compressor? - ANSWERWould
cause the current to increase and the motor may trip on overload.
On a service call for a cooling problem with a heat pump, your inspections find a liquid
line that has condensation on it. What is most likely to cause this? -
ANSWERRestriction in the liquid line.
What is a reason for cool air complaints when a heat pump is operating in the heating
cycle? - ANSWERExcessive supply air velocities.
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
ANSWERS 100% SOLVED
On an R-22 system, line diameters and lengths are typically specified for a vapor
pressure drop that does not exceed what? - ANSWER6-7PSI or 6F
What is the primary purpose of using flux when soldering copper or brass parts? -
ANSWERPrevent Oxidation
What are the three things that happen when a heat pump is cycled into the defrost
mode? - ANSWERReversing valve switches to cooling mode, Outdoor fan is shut off,
and auxiliary heat is energized.
What is a duct system that has a single trunk extending in one or two directions with
many branch ducts? - ANSWERExtended Plenum Duct System
What is the effect on supply airflow when static pressure on the return is reduced? -
ANSWERAirflow will be increased.
What is the voltage most often used to power the outdoor unit in a residential system? -
ANSWER240V Single Phase
What happens if you increased suction pressure on a reciprocating compressor? -
ANSWERThe capacity would decrease.
The refrigerants typically used in residential and light commercial pumps have a storage
life of? - ANSWERAn indefinite length of time.
A restricted drier can cause what? - ANSWERLower than normal suction pressure
What blower motor type is generally used on air handling equipment with capacities of
4,000 cfm or greater? - ANSWERBelt driven with three phases.
Electronic air cleaners can operate with internal voltages as high as? - ANSWER5000V
A system is supplied from the factory with charge for a 15 foot line set. The data plate
shows the required system charge to be 5 pounds 10 ounces. The line set uses a 3/8
inch liquid line and is 25 feet long. The manufacturer's instruction sheet specifies 0.6
ounces of refrigerant to be added for each added foot of refrigerant line length. How
much refrigerant is needed to completely charge the system? - ANSWER6lbs
, Where are drive slips typically installed? - ANSWEROn the shorter sides of rectangular
duct.
What is a necessary check to properly set a heat anticipator? - ANSWERHeating
control circuit amperage
draw.
A heat pump operating in normal ice free conditions maintains a certain temperature
difference between the outdoor coil temperature and the surrounding outdoor ambient.
What is this temperature referred to as? - ANSWERCoil TD.
What is the smallest refrigerant leak that an electronic leak detector should be capable
of sensing? - ANSWER.o5oz per year.
When checking the pressures in an operating system with a manifold gauge set, will
refrigerant oil in a hose will have an effect on the gauge? - ANSWERNo
What is the absolute pressure at sea level if a gauge pressure is 35 psig? -
ANSWER49.7psia
100,000 BTUH output furnace.
Return air temp is 65F.
Supply air is 135F.
What is the CFM? - ANSWER1323CFM
What is the best method of repair when a residential supply diffuser is noisy because of
a loose vane? - ANSWERReplace the diffuser.
When performing preventive maintenance on a heat pump what should the technician
check and why? - ANSWEROutdoor fan. To be certain it runs freely with no binding.
What is the effect of 170 volts supplied to a 208/230 volt compressor? - ANSWERWould
cause the current to increase and the motor may trip on overload.
On a service call for a cooling problem with a heat pump, your inspections find a liquid
line that has condensation on it. What is most likely to cause this? -
ANSWERRestriction in the liquid line.
What is a reason for cool air complaints when a heat pump is operating in the heating
cycle? - ANSWERExcessive supply air velocities.
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
