NATE air to air heat pump 4 heat pumps
The primary function of a reversing valve is to... - ✔✔ correct answer Switch between heating and
cooling
A typical 4 way reversing valve has 3 ports on one side of the valve body, and a single port on the
opposite side of the valve body. To what is this single port connected? - ✔✔ correct answer The
discharge line
Of the three ports on one side of the reversing valve's body, to what is the center port connected? - ✔✔
correct answer The accumulator
If a heat pump system is low on charge, then the reversing valve... - ✔✔ correct answer Is less likely to
slide
If a reversing valve is leaking under the side, then... - ✔✔ correct answer The pressures will equalize
Most defrost requirements occur at what outdoor temperature? - ✔✔ correct answer Between 35 and
45
The ambient temperature sensor for a heat pump's defrost system should be located... - ✔✔ correct
answer In the inlet air stream to the outdoor unit
If a heat pump's defrost system is initiated by temperature difference, then as the outdoor coil ices up... -
✔✔ correct answer The temperature difference increases to initiation
If a heat pump's defrost system is initiated by pressure difference, then as the outdoor coil ices up... -
✔✔ correct answer The pressure difference increases to initiation
Once defrost is initiated, what else usually happens? - ✔✔ correct answer All of the above: outdoor fan
is shut off, the reversing valve is switched to the cooling mode, emergency heat strips are energized
The balance point of a heat pump can best be described as... - ✔✔ correct answer The point at which
the building's heat loss equals the heat pump's ability to provide heat
The primary function of a reversing valve is to... - ✔✔ correct answer Switch between heating and
cooling
A typical 4 way reversing valve has 3 ports on one side of the valve body, and a single port on the
opposite side of the valve body. To what is this single port connected? - ✔✔ correct answer The
discharge line
Of the three ports on one side of the reversing valve's body, to what is the center port connected? - ✔✔
correct answer The accumulator
If a heat pump system is low on charge, then the reversing valve... - ✔✔ correct answer Is less likely to
slide
If a reversing valve is leaking under the side, then... - ✔✔ correct answer The pressures will equalize
Most defrost requirements occur at what outdoor temperature? - ✔✔ correct answer Between 35 and
45
The ambient temperature sensor for a heat pump's defrost system should be located... - ✔✔ correct
answer In the inlet air stream to the outdoor unit
If a heat pump's defrost system is initiated by temperature difference, then as the outdoor coil ices up... -
✔✔ correct answer The temperature difference increases to initiation
If a heat pump's defrost system is initiated by pressure difference, then as the outdoor coil ices up... -
✔✔ correct answer The pressure difference increases to initiation
Once defrost is initiated, what else usually happens? - ✔✔ correct answer All of the above: outdoor fan
is shut off, the reversing valve is switched to the cooling mode, emergency heat strips are energized
The balance point of a heat pump can best be described as... - ✔✔ correct answer The point at which
the building's heat loss equals the heat pump's ability to provide heat
