NATE Heat Pump Questions with Complete
Solutions
The terms grille and register are often used interchangeably. There is a difference between these
two components. The primary difference between a grille and a register is... a register is
equipped with an air volume control device and a grille is not
Thermostatic expansion valves (TXV) meter refrigerant flow to a coil to... maintain
superheated refrigerant leaving the coil
Some electromechanical type thermostats require connections to both the hot side and common
side of the low voltage transformer because... the display lights must be powered using both
sides of the line
Disc type temperature limit controls, used to protect auxiliary heat elements from overheating are
always... auto reset by temperature
Disc type, close-on rise pressure control is being used as loss-of-charge limit control on the
liquid line of a heat pump. The control must sense a specified pressure within 15 seconds of a
,compressor start for the compressor to continue operation. If the cut-in setting of the control
drifts lower... the system is less likely to shut down as a result of a small leak
The sensor of an outdoor ambient thermostat for a heat pump system typically installed in...
the entering airstream to the outdoor coil
A high pressure limit control, used to shut down a compressor if condensing pressure becomes
excessive is... typically installed to sense compressor discharge line pressure
Low pressure limit controls are often placed in the suction line of a heat pump for two purposes...
They are to protect the compressor if suction pressure drops too low
Detect a loss of a charge
The function of a reversing valve is to... provide heating and/or cooling
The relationship between inrush current and holding current of a relay coil is... insrush
current is always greater than holding current
, The timing specification of sequencers if often marked on the device using a code similar to H1-
24 C45-75. The specification for this particular sequencer marked with this code is... Contacts
close 1 to 24 seconds after coil is energized
Contacts open 45 to 75 seconds after coil is de-energized
A seven day programmable thermostat can program a different daily schedule which is used for...
the next seven days only
The capability of electronic programmable room thermostat is to... reset the set point early so
that the space temperature reaches a set temperature at a specific time is called computed
recovery
An important reason for using electronic controls is... they can make decisions based on
many inputs
One method used with electronic defrost controls to determine the need for defrost is to... use
two temperature sensors
Solutions
The terms grille and register are often used interchangeably. There is a difference between these
two components. The primary difference between a grille and a register is... a register is
equipped with an air volume control device and a grille is not
Thermostatic expansion valves (TXV) meter refrigerant flow to a coil to... maintain
superheated refrigerant leaving the coil
Some electromechanical type thermostats require connections to both the hot side and common
side of the low voltage transformer because... the display lights must be powered using both
sides of the line
Disc type temperature limit controls, used to protect auxiliary heat elements from overheating are
always... auto reset by temperature
Disc type, close-on rise pressure control is being used as loss-of-charge limit control on the
liquid line of a heat pump. The control must sense a specified pressure within 15 seconds of a
,compressor start for the compressor to continue operation. If the cut-in setting of the control
drifts lower... the system is less likely to shut down as a result of a small leak
The sensor of an outdoor ambient thermostat for a heat pump system typically installed in...
the entering airstream to the outdoor coil
A high pressure limit control, used to shut down a compressor if condensing pressure becomes
excessive is... typically installed to sense compressor discharge line pressure
Low pressure limit controls are often placed in the suction line of a heat pump for two purposes...
They are to protect the compressor if suction pressure drops too low
Detect a loss of a charge
The function of a reversing valve is to... provide heating and/or cooling
The relationship between inrush current and holding current of a relay coil is... insrush
current is always greater than holding current
, The timing specification of sequencers if often marked on the device using a code similar to H1-
24 C45-75. The specification for this particular sequencer marked with this code is... Contacts
close 1 to 24 seconds after coil is energized
Contacts open 45 to 75 seconds after coil is de-energized
A seven day programmable thermostat can program a different daily schedule which is used for...
the next seven days only
The capability of electronic programmable room thermostat is to... reset the set point early so
that the space temperature reaches a set temperature at a specific time is called computed
recovery
An important reason for using electronic controls is... they can make decisions based on
many inputs
One method used with electronic defrost controls to determine the need for defrost is to... use
two temperature sensors
