NATE: Heat Pumps
What is the purpose of the reversing valve on an air-to-air heat pump: - ANSIt changes the flow
of the refrigerant, making the indoor coil the condenser during the winter months
On a reversing-valve solenoid, what is connected to the top tube: - ANSthe compressor
discharge line
On a reversing-valve solenoid, what is connected to the bottom center tube: - ANSthe
compressor suction line
What pressure difference must be between the low side and the high side of the heat pump
system for the reversing valve to operate properly: - ANS75 psig
Where are the check valves located on an air-to-air heat pump: - ANSon the outdoor coil and
indoor coil
How are the check valves connected in a heat pump system: - ANSin parallel with both
metering devices+in series with one metering device and parallel with the other
A ball-type check valve must be installed: - ANSvertically, with the seat on the bottom of the
valve
When installing a ball-type check valve, what must be done to prevent warping: - ANSA heat
sink must be used when brazing it into the line
Where is the accumulator located on a heat pump system: - ANSbetween the bottom center
tube of the reversing valve and the compressor
When would you most likely find liquid in the vapor line on a heat pump: - ANSduring the
heating mode after a defrost
What component must always be de-energized during the defrost cycle on a heat pump: -
ANSthe outdoor fan
Why are the auxiliary strip heaters energized during the defrost cycle: - ANSto increase
supply-air temperature for comfort
What position must the reversing valve be in during the defrost cycle: - ANSthe cooling mode
When a heat pump switches into the defrost cycle, it must: - ANSremain in defrost until the
outdoor coil has reached a predetermined temperature
What is the purpose of the reversing valve on an air-to-air heat pump: - ANSIt changes the flow
of the refrigerant, making the indoor coil the condenser during the winter months
On a reversing-valve solenoid, what is connected to the top tube: - ANSthe compressor
discharge line
On a reversing-valve solenoid, what is connected to the bottom center tube: - ANSthe
compressor suction line
What pressure difference must be between the low side and the high side of the heat pump
system for the reversing valve to operate properly: - ANS75 psig
Where are the check valves located on an air-to-air heat pump: - ANSon the outdoor coil and
indoor coil
How are the check valves connected in a heat pump system: - ANSin parallel with both
metering devices+in series with one metering device and parallel with the other
A ball-type check valve must be installed: - ANSvertically, with the seat on the bottom of the
valve
When installing a ball-type check valve, what must be done to prevent warping: - ANSA heat
sink must be used when brazing it into the line
Where is the accumulator located on a heat pump system: - ANSbetween the bottom center
tube of the reversing valve and the compressor
When would you most likely find liquid in the vapor line on a heat pump: - ANSduring the
heating mode after a defrost
What component must always be de-energized during the defrost cycle on a heat pump: -
ANSthe outdoor fan
Why are the auxiliary strip heaters energized during the defrost cycle: - ANSto increase
supply-air temperature for comfort
What position must the reversing valve be in during the defrost cycle: - ANSthe cooling mode
When a heat pump switches into the defrost cycle, it must: - ANSremain in defrost until the
outdoor coil has reached a predetermined temperature
