C
HVAC NATE HEAT PUMP verified A+ questions and
answers.
Terms in this set (195)
Vapor line diameter and length 2-3 PSI or 2 degrees Fahrenheit
should be sized for a pressure
drop not to exceed
While bending soft copper tubing The cross sectional area of the tubing must not be significantly reduced
Improperly draining heat Will cause ice buildup and capacity loss
pump defrost runoff
Package unit curb gaskets Reduce sound transmission and prevent water leaks
A system evacuation is When the vacuum pressure reaches and hold 500 microns or less
considered complete
A leaking system should first be For visual traces of oil
inspected
To determine superheat You must measure suction line pressure and temperature
Rectangular duct drive slips are Installed on the shorter side of duct
Heating control circuit amp draw In order to set thermostat heat anticipator
must be measured
Outdoor unit voltage drop is With the unit running, Then when it is off
measured
Most electronic leak detectors Can detect down to .5 ounces per year
If a loose vane causes a noisy Then replace the diffuser
supply diffuser
A 230 V compressor running at Will have the current increased, and may trip on overload
170 V
Liquid line condensation Is caused by a restriction or excessive line length
Dirty return air filters Cause cool air complaints and the heat pump heating mode
Undersized ductwork causes High sound levels, insufficient air volume, and high static pressures
, A system low on charge Will cause the reversing valve to not shift or transfer
To check a suspected shorted Use an ohm-meter and check for continuity between the
compressor motor winding compressor terminals and ground
A direct drive blower wheel has It causes loss and airflow, excessive motor wear, and increase noise
bent vanes
In an electrical circuit A corroded wire to terminal connection acts like a resistor
A flexible supply duct is leaking You should check all connections, including inner and outer layers
When changing out an evaporator You must be certain to level the condensate pan
coil
The maximum external static 5 tons or les, is 1 in WC (residential)
pressure for blowers used for
heating and cooling
Location of a condenser unit Because excessive noise is disruptive to the customer
considers the operating sound
level
A wet bulb reading that is very Means the relative humidity is very high
close to the dry bulb reading
To properly evaluate a system in You would measure supply temperature, register velocity, and CFM
the
heating mode of a feeling drafty
complaint
A line set encased within an Is subject to condensation on the suction line
exterior wall
An extended Plenum duct system Single trunk extending in one or two directions with many branch ducts
is
Supply airflow is increased when Static pressure on the return is reduced
Most residential Tstat wire is 18 gauge
More tube circuits in the heat Minimizes the coil, pressure losses
pump outdoor coil
A restricted drier can cause... Lower than normal suction pressure
Most electronic air cleaners With 5000 V or less
Operate
A line voltage fuse is sized to: Protect the conductors
TXV's meter refrigerant flow To maintain superheated refrigerant leaving the coil
to the evaporator coil
Some electromechanical Both hot and common hook up to transformer secondary
thermostats require
The purpose of the auto For auto switching between heat and cool as the load changes
changeover system switch on the
heat pump thermostat is
HVAC NATE HEAT PUMP verified A+ questions and
answers.
Terms in this set (195)
Vapor line diameter and length 2-3 PSI or 2 degrees Fahrenheit
should be sized for a pressure
drop not to exceed
While bending soft copper tubing The cross sectional area of the tubing must not be significantly reduced
Improperly draining heat Will cause ice buildup and capacity loss
pump defrost runoff
Package unit curb gaskets Reduce sound transmission and prevent water leaks
A system evacuation is When the vacuum pressure reaches and hold 500 microns or less
considered complete
A leaking system should first be For visual traces of oil
inspected
To determine superheat You must measure suction line pressure and temperature
Rectangular duct drive slips are Installed on the shorter side of duct
Heating control circuit amp draw In order to set thermostat heat anticipator
must be measured
Outdoor unit voltage drop is With the unit running, Then when it is off
measured
Most electronic leak detectors Can detect down to .5 ounces per year
If a loose vane causes a noisy Then replace the diffuser
supply diffuser
A 230 V compressor running at Will have the current increased, and may trip on overload
170 V
Liquid line condensation Is caused by a restriction or excessive line length
Dirty return air filters Cause cool air complaints and the heat pump heating mode
Undersized ductwork causes High sound levels, insufficient air volume, and high static pressures
, A system low on charge Will cause the reversing valve to not shift or transfer
To check a suspected shorted Use an ohm-meter and check for continuity between the
compressor motor winding compressor terminals and ground
A direct drive blower wheel has It causes loss and airflow, excessive motor wear, and increase noise
bent vanes
In an electrical circuit A corroded wire to terminal connection acts like a resistor
A flexible supply duct is leaking You should check all connections, including inner and outer layers
When changing out an evaporator You must be certain to level the condensate pan
coil
The maximum external static 5 tons or les, is 1 in WC (residential)
pressure for blowers used for
heating and cooling
Location of a condenser unit Because excessive noise is disruptive to the customer
considers the operating sound
level
A wet bulb reading that is very Means the relative humidity is very high
close to the dry bulb reading
To properly evaluate a system in You would measure supply temperature, register velocity, and CFM
the
heating mode of a feeling drafty
complaint
A line set encased within an Is subject to condensation on the suction line
exterior wall
An extended Plenum duct system Single trunk extending in one or two directions with many branch ducts
is
Supply airflow is increased when Static pressure on the return is reduced
Most residential Tstat wire is 18 gauge
More tube circuits in the heat Minimizes the coil, pressure losses
pump outdoor coil
A restricted drier can cause... Lower than normal suction pressure
Most electronic air cleaners With 5000 V or less
Operate
A line voltage fuse is sized to: Protect the conductors
TXV's meter refrigerant flow To maintain superheated refrigerant leaving the coil
to the evaporator coil
Some electromechanical Both hot and common hook up to transformer secondary
thermostats require
The purpose of the auto For auto switching between heat and cool as the load changes
changeover system switch on the
heat pump thermostat is
