NATE Heat Pump Questions with Complete Solutions, A+

When checking the pressures in an operating system with a manifold gauge set, refrigerant oil in a hose will have ___ ______ on the gauge reading - Correct Solution No effect At sea level, a gauge pressure of 35 psig is equal to an absolute pressure of - Correct Solution 49.7 psia A technician measures the return air temperature of a 100,000 Btu output furnace to be 65°F and the supply side air temperature is 135°F. The CFM would be - Correct Solution 1323 (TD= 135-65=70️100,000/TDx1.08 ️100,000/75.6=1323) A residential supply diffuser that is noisy because of a loose vane is best serviced by - Correct Solution Replacing the diffuser When performing preventive maintenance on a heat pump the technician should check the outdoor fan to be certain that the fan - Correct Solution runs freely with no binding What is the effect of 170 volts supplied to a 208/230 volt compressor would cause a current - Correct Solution increase and the motor may trip on overload On a service call for a cooling problem with a heat pump, your inspections find a liquid line that has condensation on it. The most likely cause would be the - Correct Solution liquid line is restricted A reason for cool air complaints when a heat pump is operating in the heating cycle is - Correct Solution excessive supply air velocities A dirty or clogged air filter in an operating heat pump system can cause - Correct Solution inadequate heating To minimize noise problems in residential duct systems, the range (recommended to maximum) of design air velocity in the rectangular main supply trunk is - Correct Solution 700 to 900 fpm The effect of adding a charge to sub cooling is - Correct Solution it increases it When a capillary tube is overcharged you would get a ____ superheat and ____ sub cooling - Correct Solution Low,high In a single zone system; if a customer complains of feeling damp or sticky the cause could be - Correct Solution unconditioned air being pulled into the duct work through holes in the duct When performing indoor air balancing tests the t-stat should be set to bring on the indoor fan on - Correct Solution mid-high speed. Most manufacturers recommend the smallest allowable t-stat wire at - Correct Solution 18 AWG Checking voltage input to a compressor should take place at the - Correct Solution load side of the contactor There are more circuits in a HP outdoor coil than in an A/C outdoor coil to minimize - Correct Solution refrigerant pressure drop. Inefficient voltage or current to a solenoid will result in - Correct Solution vibration or chatter of the solenoid. A compressor that is suspected to be grounded to its' housing should be checked for - Correct Solution continuity from the terminal windings to ground. The coil of a potential relay is connected to the - Correct Solution common and start terminals of a compressor When the load on a HP in cooling mode decreases the suction pressure goes ____ and the discharge pressure goes ____ - Correct Solution Up,down