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131 Cards in this Set
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 Back
 3rd side (hint)
The ability to utilize all types of communication skills is _______________ to the HVACR technician. 
Very important 


It is important to be _________, ____________, and ____________ in filling out service orders so that office staff, other technicians, and customers know what work you completed on the job. 
Clear Complete Concise 


When explaining to the customer that you adjusted the system charge, the most appropriate term is ____________. 
Refrigerant. 


Listening carefully to what a customer is telling you: 
Can help you diagnose the problem. 


When you arrive at the service call and meet the customer, you should: 
Listen to the customer first, then ask questions. 


What is the volume of a room that measures 10' x 20' with an 8' ceiling 
1600cu ft 
Volume = L x W x H 

What is the CFM requirement for an 1800ft2 house with 8' ceilings if 5 air changes are needed per hour? 
1200CFM 
CFM = (Volume x Air Changes) / 60 

What is the CFM requirement for an 2400ft^2 house with 8' ceilings if 5 air changes are needed per hour?

1600CFM 
CFM = (Volume x Air Changes) /
60 

What is the crosssectional area of a 10" round duct? 
79"^2 
Area = pi x radius^2 

How fast does air move through a square or round duct with a velocity pressure of .2" in WC? 
1800feet/minute 
Velocity = 4005 x sqrt(Vp) 

Customers depend on you to be: 
Honest Loyal Patient 


Before leaving a service call, you should: 
Be sure to demonstrate system operation and describe basic maintenance procedures to the customer. 


What are the the advantages of using a tube cutter to cut copper pipe? 
It can be used on hard or soft drawn copper, it leaves no metal shavings to contaminate the system, and it produces a clean, square cut. 


Spring type tube benders may be used on: 
Soft drawn copper. 


A flaring tool is used to: 
Make a mechanical joint in tubing. 


A swagging tool is used to: 
Solder (braze) tubing without the use of couplings. 


What is one of the advantages of a glass stem thermometer? 
It is very accurate. 


In discussing human comfort, the temperature most commonly referred to is: 
Drybulb 


A sling psychrometer uses two glass stem thermometers. One measures drybulb, the other measures ____________. 
Wetbulb. 


A standard refrigerant manifold uses what type of element to measure pressure? 
Bourdon tube. 


What is the pressure range of a standard compound gauge on a refrigerant manifold? 
30inHg  500psig (Over pressure or retard scale from 250  500psig) 


What is the best tool for removing moisture and noncondensables from a system before adding refrigerant? 
Vacuum pump. 


A vacuum gauge reads pressure in: 
Microns. 


Three types of leak detection are: 
Soap bubbles Electronic Ultrasonic 


To prevent the release of refrigerant into the atmosphere when removing it from a system, what type of equipment must be used? 
Recovery machine. 


An anemometer uses a small fan blade to measure: 
Air velocity. 


What is one of the benefits of using silver brazing rods for coppertocopper joints? 
No flux is required. 


"Housekeeping" includes: 
Disposal of waste Fire prevention and protection Proper storage of materials 


What type of eye protection should you wear when drilling overhead? 
Goggles. 


What agency regulates cylinders and chemicals transported in a service vehicle? 
DOT (Department of Transportation) 


Material Safety Data Sheets (MSDS) contain: 
Information about personal protective equipment. 


When should oxygen be used in a refrigerant system? 
Never. 


Which classification of fire extinguisher should be used for electrical fires? 
Class C 
A Standard combustibles (garbage, paper, etc) B Liquids (oil, grease, solvents) C Electrical 

Hazardous atmospheres in confined spaces can be described as one or any combination of: 
Asphyxiating Toxic Flammable 


"Low oxygen levels" describes a(n): 
Asphyxiating atmosphere. 


If a ladder is placed against a wall that is 20' tall, what is the proper distance away from the wall for the base of the ladder? 
5 feet 
4:1 Rule 

When using a ladder you should: 
Always maintain three points of contact. 


What is the most important safety precaution that you can take when working on electrical equipment? 
Disconnect and lockout power before starting, unless testing requires the power to be on. 


When does a Ground Fault Curcuit Interrupter (GFCI) open an electrical circuit? 
When current travels through a ground path other than neutral. 


Proper lockout/tagout procedures state that locks places on a lockout device: 
May be removed only by the person who installed the locks. 


A natural cooling process produced by moisture on the skin changin to low pressure steam is called: 
Evaporation. 


During the heating season, human comfort can be enhanced without changing the temperature by: 
Adding moisture. 


Using the cooling season, dampers on bypass humidifiers should be: 
Fully closed. 


All matter can exist as a: 
Solid Liquid Gas 


Stored energy is called _________ energy 
Potential 


Heat you can feel and measure directly with a thermostat is called: 
Sensible heat. 


The heat energy exchange associated with a pressure (state) change is called: 
Latent heat. 


The amount of heat (BTU) needed to raise the temperature of 1lb of a substance 1 degree Fahrenheit is called the _______________ of the substance. 
Specific heat 


The latent heat of fusion is the amount of energy required to change 1lb of a substance from the __________ phase to the __________ phase. 
Liquid Solid 


At 32 deg F, 1lb of ice can be changed to 1lb of water by adding ___________ 
144 BTU 


At 212 deg F, 1lb of water can be changed to 1lb of steam by adding ___________ 
970 BTU 


When liquid and vapor phases of a substance exist together, and no more liquid can vaporize without more energy being added, the vapor is said to be: 
Saturated. 


When a vapor is heated to a temperature higher than its saturation point, both the added heat and the temperature above saturation are called _____________ 
Super heat. 


The process of molecules escaping from the surface of a liquid is called ____________ 
Evaporation. 


The process of a solid turning directly into a gas without going through the liquid state is called____________ 
Sublimation. 


The continuous movement of molecules within a liquid or a gas is called ____________ energy. 
Kinetic 


___________ includes both latent and sensible heat energy. 
Enthalpy 


The measurement of the force that gravity exerts is called __________ 
Weight. 


The amount of matter in a substance is called: 
Mass. 


The weight per unit of volume, or mass per unit of volume is called __________ 
Density. 


Volume per unit of mass of weight is called: 
Specific volume. 


Under standard conditions, air weighs approximately ___________ 
0.075 lbs/cu ft 


What is the formula for converting Fahrenheit to Celsius? 
C = (F  32) x 5/9 


What is the formula for converting Celsius to Fahrenheit? 
F = (C x 9/5) + 32



Solve to find the Fahrenheit temperature corresponding to 30C 
86F 
F = (C x 9/5) + 32


Solve to find the Fahrenheit temperature corresponding to 20C 
68F 
F = (C x 9/5) + 32


Solve to find the Celsius temperature corresponding to 80F 
26.7C 
C = (F  32) x 5/9


Solve to find the Celsius temperature corresponding to 60F 
15.6C 
C = (F  32) x 5/9


What is the formula used to determine air volume as heat is added? 
Vf = Vi x (Tf / Ti) Where: T = Temp in F + 460 


What is the new volume of 1ft3 of air at 0F when heated to 100F? 
1.2ft3 
Vf = Vi x (Tf / Ti)
Where: T = Temp in F + 460 Vf = 1 x (560 / 460) Vf = 1 x (1.2173....) Vf = 1.2 

The law that applies to the total pressure exerted by a mixture of gasses or vapor is: 
Dalton's Law



A coulomb of charge is ______________ electrons. 
6.28 x 10^8 


A(n) _________ is a measurement of electron flow. 
Ampere 


Voltage is best described as: 
The force that moves electrons through a circuit. 


A substance that permits the free movement of electrons is called: 
A conductor. 


Which conductors have the least resistance? 
Short, large diameter conductors. 


If the voltage in a circuit is doubled, and the resistance remains the same, the current will: 
Double. 
I = E/R 

What is th voltage of a curcuit if the resistance is 5 ohms and the current is 5A? 
25v 
E = I x R 

A circuit has a voltage of 10v and a current of 5A. What is the resistance? 
2 ohms 
R = E/I 

Total resistance of a series curcuit is: 
Equal to the sum of all resistances in the circuit. 


The total current in a parallel curcuit is: 
The sum of the currents through the individual paths. 


The rate of doing work is called __________ 
Power. 


One Kw is equal to: 
1,000 watts 


What is the power in a circuit that has a current of 10A and a resistance of 10ohms? 
1Kw (1,000w) 
P = I^2 x R 

The voltage induced in each turn of the secondary coil of a transformer is: 
The same as the voltage per turn of the primary coil. 


The load rating of a transformer is stated in: 
Voltamperes 


An AC induction motor consists of a stationary part called the ___________ and a rotating part called the ___________. 
Stator Rotor 


What is the formula used to determine synchronous speed of a three phase motor? 
RPM = (Hz x 120) / # of poles 


What is the synchronous speed of a three phase motor that has 6 poles and is operating on a 60Hz alternating current? 
1200RPM 
RPM = (Hz x 120) / # of poles
RPM = (60 x 120) / 6 RPM = 7200 / 6 RPM = 1200 

How does the power factor of an inductive motor affect efficiency? 
The lower the power factor, the less efficient the motor is. 


Which single phase AC motor does not have a start winding? 
Shadedpole 


A centrifugal switch opens the start winding curcuit when a capacitorstart motor reaches _________ of full speed. 
7580% 


A run capacitor is always connected to the _______ and ________ terminals. 
Start Run 


Terminal number 1 on all potential relays is always connected to the _____________. 
Start capacitor. 


The coil of a voltage relay is located between terminals _____________ of the relay. 
2 and 5 


What type of AC motor has the highest starting torque and the greatest efficiency? 
Three phase 


How many terminals does a dualvoltage three phase motor have? 
9 


The primary function of any wiring diagram is: 
To aid the technician in finding the problem. 


How many functions is an individual circuit in a control system designed to control? 
One 


The five basic components of all schematics are: 
A power supply A path A load A switch A legend 


The intention of the overall schematic is: 
To show how the curcuit functions. 


The type of schematic that provides the most helpful troubleshooting information for the service technician is a: 
Ladder diagram. 


Devices that consume power and convert it to some other form of energy, such as motion or heat, are called: 
Loads. 


The normal dividing lines for voltage changes in a schematic is the: 
Transformer. 


The part of the schematic that lists and explains the system components is called the _________. 
Legend. 


Relays and contractors are ______________ control switches 
Electrically controlled 


A _____________ allows the same current to flow through all of the components. 
Series circuit 


A _______________ has multiple paths for current flow. 
Parallel circuit 


That types of circuits are primarily used in control and safety applications? 
Series. 


When testing with a voltmeter, you should: 
Place the meter in parallel with the curcuit being tested. 


What does a resistance of 0 ohms across a circuit indicate? 
There is a short. 


When you use an ohmmeter, the circuit being tested: 
Must be isolated from all energy sources. 


When you test a switch with an ohmmeter, a reading of 0 ohms indicates the switch is ________. 
Closed. 


On all meters, digital and analog, the scale used should indicate the measurement: 
Close to the middle of the range. 


When testing across a closed switch in an energized circuit, you should read: 
0VAC 


When using a standard clamp on ammeter, you should: 
Make sure the jaws are closed before taking a reading. 


When testing compressor windings, you take the following readings: C to R: 2 ohms C to S: infinite resistance C to R: infinite resistance What is the diagnosis? 
Start winding is open. 


Capacitance meters must be used on capacitors that: 
Have been removed from the circuit. 


When testing a thermostat wire that has been removed from the curcuit, you measure 0 ohms between red and white. 
This indicates that there is a short. 


When testing with an ammeter, you should place the meter: 
In series with the circuit being tested. 


How do you calculate PSIA? 
PSIG + 14.7 


In Ohm's law, the variables P, I, E, and R, are used to represent different electrical terms. What does each represent? 
P  watts I  amperes E  volts R  resistance 


How do you calculate the cross sectional area of a rectangular or square duct? 
Length (in feet) x Width (in feet) 


How do you calculate the cross sectional area of a round duct?

Area = pi x radius^2 


How do you determine the required CFM for a building or room based on number of air changes needed per hour? 
(Volume x #of air changes needed) / 60 Volume = L x W x H 


How do you determine duct air velocity (in FPM) using velocity pressure as a known variable? 
Velocity = 4005 x sqrt Vp 


How do you calculate CFM using duct air velocity and duct cross sectional area as known variables? 
CFM = V x A 


How do you maintain consistent duct cross sectional area in scenarios where the width or height must be adjusted, such as to fit through an obstacle? 
H1 x W1 = H2 x W2 H1 and W1 are the dimensions of the original duct. 


Which schematic is useful for quickly visualizing each component? 
Pictorial schematic. 


In order for an agreement to be legally binding, it must be ___________. 
In writing. 


To change the direction of a fan run by a three phase induction motor, you must _____________. 
Switch two of the leads into opposite positions. If the system has a "high leg" only switch the two "low legs". 
