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Air Conditioning Certification Exam Part 1
Terms in this set (49)
The British Thermal Unit (Btu)
The standard unit for measuring the quantity of heat in a substance is....
Pressure which cannot be further reduced
Zero psia (pounds per square inch absolute) is....
Store liquid refrigerant
A liquid receiver is used to....
Low suction pressure and low discharge pressure
A low refrigerant charge in an air conditioning system will cause these symptoms...
High suction pressure and higher than normal discharge pressure
A TXV sensing bulb which becomes detached from the suction line will cause these symptoms....
Warmer than the evaporator inlet
In an air conditioning system that uses a thermostatic expansion valve, the temperature of the evaporator outlet will usually be....
The difference between crankcase pressure and oil pressure
The oil pressure safety switch is operated by....
Compression, condensation, expansion, vaporization
The sequential order of steps in the vapor - compression process are....
By flushing the system and then installing filter/driers in both the liquid and suction lines
Solid contaminants, such as sludge and carbon, from a severe hermetic compressor motor burn out are best removed....
Has an effect on compressor capacity
The clearance space in a reciprocating compressor....
___________ can be used for leak detection with all high pressure refrigerants.
A thermal electric (solid state) expansion valve is controlled by....
Dew point temperature
The temperature at which moisture will start to condense from the air is called....
High head pressure
Which of the following is NOT a symptom of a hermetic system that is low on refrigerant?
Latent heat is transferred from the refrigerated space to the refrigerant
In the evaporator.....
A mixture of liquid with some "flash gas".
In a direct expansion (DX) evaporator system, the refrigerant enters the evaporator as...
Approximately 15% less
The flow rate of a TXV used in R410a system as compared to R22 systems is....
A faulty bulb or power head assembly
If the evaporator pressure does not change when heat is added or removed from the thermostatic expansion bulb, the problem may be...
A starved evaporator
A partially clogged capillary tube can cause....
Increase liquid sub cooling
A liquid-to-suction heat exchanger is other used to...
An inert gas
At a residential service call, "no cooling" complaint, the service technician finds the unit to be completely out of refrigerant. The technician decides to use a trace amount of refrigerant and _____________ in order to pressurize the system.
Air handler drain is on the negative air side
A drain trap should be installed on a split system when the....
10 degrees F
When testing the efficiency of a water cooled condenser, the refrigerant condensing temperate should be approximately ____________ higher than the leaving water temperature
Condenser and the metering device
A liquid line filter drier should be replaced between the...
Establish a minimum operating pressure in the evaporator
A low pressure cut off switch is used to....
The movement of heat by direct contact is called....
An increase in head pressure causes ___________ refrigerant to flow through the capillary tube.
De-superheats, condenses, sub cools
Which of the following represent the right order of the functions of a condenser?
The movement of heat by the way of fluid (or air) is called....
Increased head pressure
An overcharge of refrigerant will cause....
CFM = BTU / (1.08 x delta-T)
The temperature rise method for determining air fflow is.....
It is located before the metering device
Which of the following is TRUE of a solenoid valve in a pump down system?
In the liquid line, before the metering device
A sight glass would normally be located...
High suction pressure and high discharge pressure
Air and other non-condensable gasses in a capillary tube air conditioning system will cause these symptoms....
Low compressor capacity
Bubbles in a sight glass could be an indication of....
Prevent liquid refrigerant from reaching the compressor
An accumulator is used to....
Open service port with normal system flow
Back seating a two way service valve results in....
A restriction of the return air or a dirty evaporator
A customer complains that their air conditioning system is running constantly, but not cooling enough. The suction line is very cold and the compressor is sweating. The most likely cause is....
15 degrees F
The R134a high pressure gauge reads 146 psig and the liquid line temperature at the condensing unit is 95 degrees F. What is the operating system sub cooling?
Refrigerant R-134a vapor enters the condenser at 124 psig, 100 degrees F. It leaves as a liquid from the condenser sub cooled 20 degrees F and the pressure with be approximately.....
It must be installed lover than the valve body
When mounting a thermostatic expansion valve senor bulb, which of the following is not true?
Debris from the burned out compressor has clogged the drier
A customer reports that their residential split system has a compressor replaced last week by another service company. The the unit is not cooling properly. When you arrive and inspect the unit, you find that the evaporator seems to be starved for refrigerant. On examining the condensing unit, you find that the liquid line is sweating where it leaves the drier. This is most likely the result of......
They maintain a constant evaporator temperature
Which of the following is NOT true of a capillary tube metering device?
Which of the following is NOT a thermodynamic property of refrigerants?
Constant evaporator pressure
The automatic expansion valve is designed to maintain....
High suction pressure and high discharge pressure
A refrigerant overcharge in a capillary tube air conditioning system will cause these symptoms.....
Low head pressure
When a TEV or a capillary tube is used as a metering device, a low refrigerant charge will cause....
Moisture in a refrigeration system can cause.....
The valve will stay open and not maintain proper superheat
How does a TXV in an operating air conditioning unit react when the bulb is not attached to the outlet or suction line and hanging in the air?
Sets with similar terms
Air Conditioning Certification (ETI)