NATE: Heat Pumps
What is the purpose of the reversing valve on an air-to-air heat pump: - ANS-It 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: - ANS-the compressor
discharge line
On a reversing-valve solenoid, what is connected to the bottom center tube: - ANS-the
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: - ANS-75 psig
Where are the check valves located on an air-to-air heat pump: - ANS-on the outdoor
coil and indoor coil
How are the check valves connected in a heat pump system: - ANS-in parallel with both
metering devices+in series with one metering device and parallel with the other
A ball-type check valve must be installed: - ANS-vertically, with the seat on the bottom
of the valve
When installing a ball-type check valve, what must be done to prevent warping: - ANS-A
heat sink must be used when brazing it into the line
Where is the accumulator located on a heat pump system: - ANS-between 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: - ANS-during
the heating mode after a defrost
What component must always be de-energized during the defrost cycle on a heat pump:
- ANS-the outdoor fan
Why are the auxiliary strip heaters energized during the defrost cycle: - ANS-to increase
supply-air temperature for comfort
What is the purpose of the reversing valve on an air-to-air heat pump: - ANS-It 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: - ANS-the compressor
discharge line
On a reversing-valve solenoid, what is connected to the bottom center tube: - ANS-the
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: - ANS-75 psig
Where are the check valves located on an air-to-air heat pump: - ANS-on the outdoor
coil and indoor coil
How are the check valves connected in a heat pump system: - ANS-in parallel with both
metering devices+in series with one metering device and parallel with the other
A ball-type check valve must be installed: - ANS-vertically, with the seat on the bottom
of the valve
When installing a ball-type check valve, what must be done to prevent warping: - ANS-A
heat sink must be used when brazing it into the line
Where is the accumulator located on a heat pump system: - ANS-between 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: - ANS-during
the heating mode after a defrost
What component must always be de-energized during the defrost cycle on a heat pump:
- ANS-the outdoor fan
Why are the auxiliary strip heaters energized during the defrost cycle: - ANS-to increase
supply-air temperature for comfort
