NATE HEAT PUMP QUESTIONS WITH COMPLETE VERIFIED ANSWERS

NATE HEAT PUMP QUESTIONS WITH COMPLETE VERIFIED ANSWERS R-22 vapor line diameters and lengths are typically specified for a vapor pressure drop that does not exceed - ANSWER-6-7 psi or 6 degrees F The primary purpose of using flux when soldering copper or brass parts is to prevent - ANSWER-Oxidation The water that results from a defrost cycle of an air to air heat pump (runoff) must drain off and away from the outdoor coil to prevent - ANSWER-Excessive ice build up The component used to reduce sound transmission and prevent water leaks of a packaged heat pump installed on a roof is the - ANSWER-Curb gasket When under a deep vacuum, a hermetic refrigeration compressor's motor windings could be ________ if energized - ANSWER-Damaged In order for an evacuation to be considered complete, a heat pump refrigerant circuit should be evacuated to a vacuum pressure of - ANSWER-500 microns or below A system is supplied from the factory with charge for a 15-foot line set. The data plate shows the required system charge to be 5 pounds 10 ounces. The line set uses a 3/8-inch liquid line and is 25 feet long. The manufacturer's instruction sheet specifies 0.6 ounces of refrigerant to be added for each added foot of refrigerant line length so the total refrigerant charge for the system would be - ANSWER-6 lbs(25-15=10 10x0.6=6oz 6oz+5lbs 10oz= 5lbs 16oz the equivalent of 6lbs) Drive slips are typically installed on the __________ sides of rectangular ducts - ANSWER-Shorter To properly set a heat anticipator it is necessary to check the - ANSWER-heating control circuit amperage draw A heat pump operating in normal ice free conditions maintains a certain temperature difference between the outdoor coil temperature and the surrounding outdoor ambient. This temperature difference is referred to as - ANSWER-Coil TD (temperature difference) The smallest refrigerant leak that an electronic leak detector should be capable of sensing is - ANSWER-0.05 oz. per year When checking the pressures in an operating system with a manifold gauge set, refrigerant oil in a hose will have ___ ______ on the gauge reading - ANSWER-No effect At sea level, a gauge pressure of 35 psig is equal to an absolute pressure of - ANSWER-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 - ANSWER-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 - ANSWER-Replacing the diffuser When performing preventive maintenance on a heat pump the technician should check the outdoor fan to be certain that the fan - ANSWER-runs freely with no binding What is the effect of 170 volts supplied to a 208/230 volt compressor would cause a current - ANSWER-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 - ANSWER-liquid line is restricted A reason for cool air complaints when a heat pump is operating in the heating cycle is - ANSWER-excessive supply air velocities A dirty or clogged air filter in an operating heat pump system can cause - ANSWER-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 - ANSWER-700 to 900 fpm The effect of adding a charge to sub cooling is - ANSWER-it increases it