NATE A C Exam -1 Questions and Complete Solutions Graded A+

Low airflow over a residential split system air conditioning evaporator can cause A: Liquid flood-back to the compressor B: A decrease in compression ratio C: An increase in suction line superheat D: Oil logging in the evaporator - Answer: A: Liquid flood-back to the compressor Which of the following is the correct sequence of work? A: Attach gauge manifold, recover refrigerant, replace filter core, evacuate the system, recharge the system. B: Recover refrigerant, evacuate the system, replace filter core, recharge the system. C: Attach gauge manifold, evacuate the system, replace filter core, recover refrigerant, recharge the system. D: Attach gauge manifold, recharge the system, evacuate the system, replace filter core. - Answer: A: Attach gauge manifold, recover refrigerant, replace filter core, evacuate the system, recharge the system. As the pressure on a liquid is increased, the vaporization temperature of the liquid A: Decreases B: Increases C: Remains unchanged D: Varies - Answer: B: Increases An oil separator must be mounted A: Level B: Below the compressor crankcase C: Above the compressor crankcase D: In the suction line - Answer: A: Level Which of the following metering devices controls evaporator pressure? A: Thermostatic expansion valve B: Fixed orifice C: Low side float D: None of these - Answer: D: None of these An automatic expansion valve controls evaporator pressure. The purpose of the external equalizer on a thermostatic expansion valve is A: To equalize evaporator pressure drop with respect to the TEV B: To equalize the evaporator pressure drop C: To help prevent liquid floodback D: To allow the high side pressure to equalize to the low side when the compressor cycles off - Answer: A: To equalize evaporator pressure drop with respect to the TEV The higher the MERV rating of a filter-drier, the A: More efficient the drier at absorbing moisture B: Less efficient the drier at absorbing moisture C: Smaller the particles the filter can entrap D: MERV does not apply to filter-driers - Answer: D: MERV does not apply to filter-driers Minimum Efficiency Reporting Value - MERV ratings are used to rate the ability of an air conditioning filter to remove dust from the air as it passes through the filter. MERV is a standard used to measure the overall efficiency of a filter. Higher MERV ratings mean fewer dust particles and other airborne contaminants pass through the filter. Filters with a merv rating of 9 to 12 are used in commercial and industrial applications and will stop particles in the 1 to 3 micron range. These filters are a great choice for home owners who want the best dust control possible. When using filters with Merv 9 ratings and above it is important to clean or replace them when recommended by the manufacturer because they will have a negative effect on air flow when they become dirty. This can lead