NATE Air-to-Air Heat Pump Exam with Correct Answers, Exams of Heat and Mass Transfer

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NATE air to air heat pump 4 heat pumps

Exam with correct answers

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 outdoor unit must be located so that... - correct answer -All of the above: roof run off is avoided, defrost water can drain away, is elevated above snow drifts. Packaged heat pumps are... - correct answer -Less expensive than split units The single most important consideration for a packaged heat pump to be mounted on a roof is... - correct answer -Can the roof support the weight of the unit? To avoid noise transmission from a packaged heat pump on a roof... - correct answer -Be sure to install the curb gasket On a typical two stage heat pump thermostat, the first stage brings on the heat pump, and the second stage energizes... - correct answer -The first stage of auxiliary heat If the thermostat's system switch is set to AUTO, then... - correct answer -The system will go into either heating, or cooling as the demand imdicates Why do some thermostats have a "C" terminal on their subbases that must be connected? - correct answer -Both sides of power are required to light the lights and the display The heating anticipator is set... - correct answer -To match the amp draw of the heating circuit An add on heat pump requires the addition of a control that will... - correct answer - Not allow the heat pump and the furnace to operate simultaneously in the heating mode

Why would a low pressure switch be placed in the low side of a heat pump? - correct answer -To sense the loss of a charge Electronic air cleaners... - correct answer -All of the above: improve IAQ, remove air borne contaminants, operate at voltages in excess of 5000 VDC An electronic air cleaner cannot remove... - correct answer -Odors An air cleaner begins to become clogged... - correct answer -It becomes more efficient An untrapped condensate drain line that is located on the inlet side of the blower will... - correct answer -Not allow the water to drain from the pan until the fan shuts off What will mitigate the damages associated with the problems encountered (in question #25 above) with an untrapped condensate drain line that will not allow the water to drain from the pan until the fan shuts off? - correct answer -Float activated switch in the pan drain Sensible heat is... - correct answer -Heat that causes a change in dry bulb temperature Latent heat can be measured using... - correct answer -None of the above: a dry bulb thermometer, a wet bulb thermometer, a hygrometer Sensible heat ratio is... - correct answer -Sensible heat / total heat After using ACCA's manual J to calculate the heat loss and heat gain of a residential structure, you would then use which of the following to choose a heat pump? - correct answer -The heat gain A gage reading of 30 psi equates to... - correct answer -44.7 psia

An evacuation of a split system heat pump is considered complete at... - correct answer -500 microns After the vacuum pump is isolated from the system, the micron gage rises to a level of 7500 microns, and stays there. What does this indicate? - correct answer -There is moisture in the system If the wet bulb and dry bulb temperatures are the same, what does this indicate? - correct answer -100% RH COP is derived by... - correct answer -Heat pump output (Btuh)/input kWh • 3413