HVAC EXCELLENCE LATEST ACTUAL QUESTIONS AND
ANSWERS RATED A+
✔✔When using an electronic leak detecter, the sensing probe - ✔✔should be moved at
approximately 1 inch every second
✔✔Moisture in the refrigeration system will cause - ✔✔Compressure Failure
✔✔In order to remove as much moisture as possible from a system - ✔✔Triple
evacuate the system to 500 microns with a deep vacuum pump
✔✔What kind of gauge is used to measure microns? - ✔✔A compound gauge
✔✔Water will vaporize at ____ temperature in a 28 inch mercury vacuum - ✔✔100
degrees faranheit
✔✔After a system has been opened and the compressor changed, the service
technician must: - ✔✔replace the filter drier, leak check, evacuate and charge
✔✔Back seating a two way service valve results in - ✔✔closed service port with normal
system flow
✔✔before a vapor/ compression system is opened for service - ✔✔the refrigerant must
be recovered using approved equipment
✔✔The R 410A compound gauge reads 124 psig and the suction line temp. at the
condensing unit is 54 degrees F. what is the operating system superheat? - ✔✔12
degrees faranheit
✔✔When topping off an operating system containing a blended refrigerant -
✔✔introduce the refrigerant a a liquid into the low side using a throttling valve.
✔✔a partially clogged capillary tube metering device can cause - ✔✔a starved
evaporator
✔✔The R134-A high pressure gauge reads 146 psig and the liquid line temp. at the
condensing unit is 95 degrees faranheit, what is the operating subcooling - ✔✔15
degrees faranheit
✔✔An overcharge of refrigerant will cause - ✔✔increased head pressure
✔✔A drain trap should be installed on a split system when the - ✔✔Air handler drain is
on the negative side
, ✔✔A customer complains that their AC system is running constantly, but not cooling
enough. The suction line is very colde and the compressor is sweating. Mostlikely cause
is - ✔✔a restriction of the return air or dirty evaporator
✔✔What is the generally accepted range for evaporator air flow in CFMs per ton of
residential air conditioning? - ✔✔350 to 450
✔✔Split system with Compressor change out, unit is not cooling. Evaporator seems
starved, liquid line is sweating leaving the drier, mostlikely - ✔✔Debris from the burned
out compressor has clogged the filter drier
✔✔The temperature rise method for determining air flow is - ✔✔CFM=BTU / (1.08 x
Delta T)
✔✔What is the recomended residential indoor relative humidity for summer? - ✔✔50%
✔✔An inefficient compressor is usually indicated by ___ headpressure and ___ suction
pressure - ✔✔Lower than normal/ higher than normal
✔✔Which is NOT a symptom of a hermetic system that is low on refrigerant - ✔✔High
head pressure
✔✔Frost on the suction line indicates - ✔✔That the temp. is below the dew point and
below 32 degrees F.
✔✔an increase in head pressure causes __ refrigerant to flow through a capillary tube -
✔✔More
✔✔With an automatic expansion valve, an increase in evaporator load will cause the -
✔✔Automatic expansion valve to open
✔✔When a TEV or a capillary tube is used as a metering device a low refrigerant
charge will cause - ✔✔low head pressure
✔✔what is the maximum operating pressure setting for an acetylene torch? - ✔✔15 psig
✔✔when connecting copper to steel, the recommended brazing filler alloy is a - ✔✔45
% silver alloy
✔✔Solid contaminants, such as sludge and carbon, from a severe hermetic compressor
motor bur out are best removed: - ✔✔by flushing the system and then installing filter/
driers in both the liquid and suction lines
ANSWERS RATED A+
✔✔When using an electronic leak detecter, the sensing probe - ✔✔should be moved at
approximately 1 inch every second
✔✔Moisture in the refrigeration system will cause - ✔✔Compressure Failure
✔✔In order to remove as much moisture as possible from a system - ✔✔Triple
evacuate the system to 500 microns with a deep vacuum pump
✔✔What kind of gauge is used to measure microns? - ✔✔A compound gauge
✔✔Water will vaporize at ____ temperature in a 28 inch mercury vacuum - ✔✔100
degrees faranheit
✔✔After a system has been opened and the compressor changed, the service
technician must: - ✔✔replace the filter drier, leak check, evacuate and charge
✔✔Back seating a two way service valve results in - ✔✔closed service port with normal
system flow
✔✔before a vapor/ compression system is opened for service - ✔✔the refrigerant must
be recovered using approved equipment
✔✔The R 410A compound gauge reads 124 psig and the suction line temp. at the
condensing unit is 54 degrees F. what is the operating system superheat? - ✔✔12
degrees faranheit
✔✔When topping off an operating system containing a blended refrigerant -
✔✔introduce the refrigerant a a liquid into the low side using a throttling valve.
✔✔a partially clogged capillary tube metering device can cause - ✔✔a starved
evaporator
✔✔The R134-A high pressure gauge reads 146 psig and the liquid line temp. at the
condensing unit is 95 degrees faranheit, what is the operating subcooling - ✔✔15
degrees faranheit
✔✔An overcharge of refrigerant will cause - ✔✔increased head pressure
✔✔A drain trap should be installed on a split system when the - ✔✔Air handler drain is
on the negative side
, ✔✔A customer complains that their AC system is running constantly, but not cooling
enough. The suction line is very colde and the compressor is sweating. Mostlikely cause
is - ✔✔a restriction of the return air or dirty evaporator
✔✔What is the generally accepted range for evaporator air flow in CFMs per ton of
residential air conditioning? - ✔✔350 to 450
✔✔Split system with Compressor change out, unit is not cooling. Evaporator seems
starved, liquid line is sweating leaving the drier, mostlikely - ✔✔Debris from the burned
out compressor has clogged the filter drier
✔✔The temperature rise method for determining air flow is - ✔✔CFM=BTU / (1.08 x
Delta T)
✔✔What is the recomended residential indoor relative humidity for summer? - ✔✔50%
✔✔An inefficient compressor is usually indicated by ___ headpressure and ___ suction
pressure - ✔✔Lower than normal/ higher than normal
✔✔Which is NOT a symptom of a hermetic system that is low on refrigerant - ✔✔High
head pressure
✔✔Frost on the suction line indicates - ✔✔That the temp. is below the dew point and
below 32 degrees F.
✔✔an increase in head pressure causes __ refrigerant to flow through a capillary tube -
✔✔More
✔✔With an automatic expansion valve, an increase in evaporator load will cause the -
✔✔Automatic expansion valve to open
✔✔When a TEV or a capillary tube is used as a metering device a low refrigerant
charge will cause - ✔✔low head pressure
✔✔what is the maximum operating pressure setting for an acetylene torch? - ✔✔15 psig
✔✔when connecting copper to steel, the recommended brazing filler alloy is a - ✔✔45
% silver alloy
✔✔Solid contaminants, such as sludge and carbon, from a severe hermetic compressor
motor bur out are best removed: - ✔✔by flushing the system and then installing filter/
driers in both the liquid and suction lines
