Air Conditioning Certification Exam Questions With Correct Answers.

A faulty condenser fan motor on an air conditioning system will cause these symptoms..... - High suction pressure and high discharge pressure When connecting copper to steel the recommended brazing filler alloy is a... - 45 percent silver alloy A partially iced over evaporator can be caused by... - An undercharge Heat added to the refrigerant in vapor state after the evaporation process is called.... - Superheat Why must refrigerant in the suction line be slightly warmer than the saturation temperature? - Prevent liquid slugging of the compressor Heat which causes a change of temperature of substance is called.... - Sensible heat The thermostatic expansion valve has three operating pressures.... - Evaporator pressure, spring pressure, and sensor bulb pressure What is the maximum operating pressure setting for an acetylene torch? - 15 psig Heat added to a substance without a rise in temperature; (example: liquid refrigerant to gas) this process is called? - Latent heat of vaporization An automatic expansion valve is best suited.... - When the load remains fairly constant If the cut-off plate is removed from a blower assembly, how would this effect blower performance? - It would reduce air flow When using an electronic leak detector, the sensor probe.... - Should be moved approximately 1 inch every two seconds A thermostatic expansion valve is designed to maintain... - Constant evaporator superheat A refrigerant gives up heat when... - It condenses 10 lbs of refrigerant passing through a water cooled condenser will lose 20 Btu's of heat per lb. If 10 lb of water passes through the condenser with an entering temperature of 80 degrees F. The temperature of the water leaving the condenser is..... - 100 degrees F Which of the following symptoms would be indicative of an oil logged condenser? - High discharge line pressure and low liquid line pressure A compressor that has a broken valve will cause these symptoms.... - High suction pressure and low discharge pressure The state of the refrigerant in the suction line should be... - Low pressure / low temperature vaporThe heat removed from the refrigerant by the condenser is.... - Both sensible and latent heat The first function of a condenser must perform is to __________ the refrigerant before condensing can occur. - De-superheat A dirty evaporator in an air conditioning system will cause these symptoms... - Low suction pressure and low discharge pressure If a small air conditioner has only a very low, insignificant refrigerant pressure drop through the evaporator coil, the manufacturer may use... - An internal equalized thermostatic expansion valve An air conditioning system that is oversized can cause.... - inefficient dehumidification of the conditioned space An inefficient compressor is usually indicated by _________ head pressure and _________ suction pressure. - Lower than normal / higher than normal Which of the following is the most important consideration in the selection of an evaporator coil? Match the coil to the.... - Condensing unit and the latent / sensible loads When testing the efficiency of an air cooled condenser, the refrigerant condensing temperature should be approximately ________ higher than the entering air temperature. - 30 degrees F Which of the following types of air conditioning compressors is most energy efficient? - Scroll The state of the refrigerant entering the condenser is.... - High pressure / high superheated vapor After a system has been opened and the compressor changed, the service technician must... - Replace the filter drier, leak check, evacuate, and charge The evaporator.... - Transfers heat from the refrigerated space to the refrigerant Liquid slugging is... - Liquid refrigerant in the compressor clearance space What is the generally accepted range for evaporator air flow in CFM's per ton of residential air conditioning? - 350 to 450 A mechanical shaft seal is necessary on a..... - Open drive compressor Frost on a suction line indicates.... - That it's temperature is below the dew point and below 32 degrees F Zero psig (pounds per square inch gauge) is... - The same as atmospheric pressure A temperature differential across a filter-drier indicates... - A restricted filter-drier A decrease in superheat causes the thermostatic expansion valve to begin to.... - Close While troubleshooting a residential split system, the service technician finds low operating pressures and low system amperage draw. This could be an indication of... - Low airflow across the evaporatorIf a 30 pound cylinder of reclaimed R-410a refrigerant has been stored over night at 70 degrees F, the pressure in the cylinder should be approximately_______. - 201 psig