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Sheet Metal 4th Yr > Trouble Shooting Lab > Flashcards

Trouble Shooting Lab Flashcards

1
Q

ELECTONIC IGNITION 110305a

What is the main different between an intermittent pilot gas valve and a direct ignition gas valve ?

A

The direct ignition gas valve has no pilot connection.

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2
Q

ELECTONIC IGNITION 110305a

When using electronic ignition, what is the process of proving the flame called ?

A

Flame Rectification

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3
Q

ELECTONIC IGNITION 110305a

What is the minimum Flame Rod to ground connection area that is immersed in the flame ?

A

1 (Flame) : 4 (area ground rod)
In order for the current to be rectified from AC to DC.
Micro amp.

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4
Q

ELECTONIC IGNITION 110305a

Why have flame conductivity systems not been used for proving the flame ?

A

The system will NOT distinguish between a flame and a short ground.

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5
Q

ELECTONIC IGNITION 110305a

What is the first step in the sequence of operation for any heating appliance with electronic ignition ?

A

There is a call for heat from the thermostat.

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6
Q

ELECTONIC IGNITION 110305a

What i?s the importance of the connection diagram ?

A

It shows where the wire go and the color of the wire.

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7
Q

ELECTONIC IGNITION 110305a

What is the importance of the ladder diagram ?

A

It shows the appliance works for troubleshooting.

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8
Q

ELECTONIC IGNITION 110305a

Inside of a furnace, which component is connected to a capacitor ?

A

Blower Motor

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9
Q

ELECTONIC IGNITION 110305a

Define : Interrupted Pilot Ignition System

A

Main burner and pilot are OFF during standby.
Call for heat : ignition system is pilot and proves it’s LIT. Then lights main burner.

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10
Q

ELECTONIC IGNITION 110305a

What is the difference between Interrupted pilot and Intermittent pilot ?

A

Intermittent the pilot continues to burn which main burner.
Cheaper, less parts

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11
Q

ELECTONIC IGNITION 110305a

Hot Surface Ignition System are usually what type of ignition ?

A

Direct Ignition

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12
Q

ELECTONIC IGNITION 110305a

What are the parts of a Dual-Rod Pilot ?

A
  1. Spark Ignitor
  2. Flame Sensor
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13
Q

ELECTONIC IGNITION 110305a

What is a HSI made of ?

A

Silicon Carbide

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14
Q

ELECTONIC IGNITION 110305a

How does a Direct-Spark Ignition System work ?

A

The system turns on the main burner gas, lights the burner and proves this flame.

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15
Q

ELECTONIC IGNITION 110305a

Do Direct Fire Ignition module has a fuse ?

A 
Older module do. 
BUT new modules don't have a fuse. 
Appliance manufacturer is left to supply a fuse protection in the wiring of appliance.
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16
Q

ELECTONIC IGNITION 110305a

What happens if the spark from the ignition touches the main burner?

A

It will blow a hole in the burner casting in time.
Spark can NEVER touch main burner.

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17
Q

ELECTONIC IGNITION 110305a

How do you handle a HSI with your fingers.

A

Only on the ceramic base.

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18
Q

ELECTONIC IGNITION 110305a

What do you use to clean a flame rod ?

A

Only Scotch Brite pads or 000 steel wool

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19
Q

ELECTONIC IGNITION 110305a

With HSI ignitors, what are the steps to flame ignition ?

A
  1. HSI is allowed to heat up pass the temperature required to ignite gas.
  2. Main gas valve is energized
  3. Ignition of the main burner takes place.
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20
Q

ELECTONIC IGNITION 110305a

What are the 2 main principles of Rod Defection Systems?

A
  1. Flame Rectification
  2. Flame Conductivity
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21
Q

ELECTONIC IGNITION 110305a

The definition of a Rectifier is :

A

Device for converting Alternating Current into Direct Current.

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22
Q

ELECTONIC IGNITION 110305a

Will flame conduct electricity ?

A

YES
Ionized particles that form from the burning gas conduct electricity.

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23
Q

ELECTONIC IGNITION 110305a

Define : Flame Ionization

A

Heat from flame causes the molecules between the electrodes to collide with each other. This removes electrons knocked off molecules and ion are formed.

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24
Q

ELECTONIC IGNITION 110305a

What are the start up sequence of step from “call for heat” to energize ignition module?

A
  1. Call for heat
  2. R-W terminates close.
  3. Energizes inducer fan relay.
  4. Starts inducer fan.
  5. Pressure switch closes. (air pressure increase in respones to fan).
  6. Allows power to flow to ignition module.
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25
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

List the 5 poarts of a relay.

A

  1. Coil
  2. Core
  3. Return Spring
  4. Armuture
  5. Contacts
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26
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

List the 4 most common arrangements for the contacts of a relay.

A
  1. SPST - NO (normally open) Single Pole Single Throw normally open contacts
  2. SPST - NC (normally closed) Single Pole Single Throw normally open contacts
  3. SPDT - Single Pole Double Throw
  4. DPDT - Double Pole Double Throw
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27
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Name the 2 most common capacitors used in HVAC systems.

A
  1. Run Capacitor
  2. Start Capacitor
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28
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What is the material called that is used to seperate the 2 plates in a capacitor?

A

Dielectric

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29
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What activates the pressure switch?

A

The pressure switch is activated when the IDM (inducor motor) starts turning and creates enough pressure, it will force the diaphragm to move toward the microswitch, closing it.

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30
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What is flame rectification?

A

Flame rectification is an AC electrical circuit that sends a very small current from the furnace electronic board-up to the flame rod. When the flame is established, the flame acts as a path or conductor, which allows the current to flow across the flame from the rod to ground (burner), thus completing the circuit.

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31
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Where is the CPU located?

A

The Electonic Control Board contains the CPU in most modern day HVAC equipment.

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32
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Define : Relay

A

A Relay is a device or remote control device that uses one or more intiating devices, such a switch, to operate or control another device connected either in the same circuit or in another circuit.

Can be operated electro-mechanically or electronic solid state components.

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33
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

On a schematic drawing what state are relay drawn in?

A

It is always shown in the de-energized state and the contacts are said to be in their normal postion; that is, the position they are in when the coil is not energized.

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34
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Concerning relays, what applacation are SPST and DPDT relays used?

A

For switching equipment off and on.

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35
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Define : Time Delay Relay type (TDOE) Time Delay On Energization.

A

When contacts change only after a specified time has passsed from the moment relay is energized.

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36
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Define : Time Delay Relay type (TDOD) Time Delay On De-energization.

A

When the contacts change instantly when the relay is energized, BUT will revert back to their original positsion only after a specified time when the relay is de-energized.

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37
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Define : Capacitance

A

Capacitance is the ability of an electrical device to store energy into an electostatic field and release energy from the electrostratic field to an electric circuit

ALSO

As the ability of an electrical device to oppose any change in voltage acrossany change in voltage across that device.

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38
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What is the International System of Units (SI) unit for Capacitance?

A

farad

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39
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Define : SI unit, Coulomb

A

SI unit of electric charge equal to the amount of charge transported by a current of 1 ampere in 1 second.

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40
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Name 3 types of Dieletric material.

A
  1. Air Dieletric (leaet capacity)
  2. Paper Dieletric (more capacity)
  3. Ceramic Dieletric (greater capacity)
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41
Q

SYSTEM CONTROLS AND SCHEMATICS 110305

What must be done befoe testing a capacitor?

A

You MUST discharge the stored energy.

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42
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What are the 2 methods you can use to de-energize a capacitor?

A
  1. Place leads of a high wattage RESISTOR on the leads of CAPACITOR.
  2. Place leads on 100watt electric BULB on the leads of the CAPACITOR
43
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What type of furnaces have induser motors ?

A

All

  1. Mid-Efficient furnaces
  2. High -Efficient furnaces
44
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What does a PRESSURE SWITCH prove in furnace operations ?

A
  1. The iducor motor (IDM) is running
  2. NO obstructions in the venting system
45
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What does a pressure switch consist of ?

A
  1. Diaphragm
  2. Microswitch
46
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Purpose od the Inducor Motor ?

A
  • Draw the correct volume of air for the heat exchange (restrictor plate, office)
  • Assist the the flue gases to rise up through venting.
47
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What is the purpose of the Flame Roll-Out Switch.

A

Its function is to detect any flame that blows back or rolls out of combustion chamber.

48
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

How many Flame Roll-Out switches are there in a furnace ?

A

2 , One on each side of the burner box.

49
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

How does a Flame Roll-Out Switch reset after it opens ?

A

It must be manually reset at switch.

There is a little red button between contacts on switch.

50
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Concerning High Limit switches, what is the switch normally in

Open or Closed

A

Normally Closed

Exposed to high temperature the switch opens.

51
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Can the set points of a High Limit Switch be changed by a HVAC journy person ?

A

No

Factory clibrated and cannot be adjusted.

52
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What is a Hot Surface Ignitor (HSI) made of ?

A

Old HSI are made of Silicon Carbide

New HSI are made of Silicon Nitrate (last twice as long)

53
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

How hot do HSI ignitors get ?

A

Raise to aproximately 2600*F (1427*C)

54
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What does CPU stand for ?

A

Central Processing Unit

55
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What is the fuction of the CPU ?

A

CPU contains a number of electronic circuits that can execute a sequence of stored instructions called computer programs.

56
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What are the 4 steps that the CPU use in their opertation ?

A
  1. Fetching
  2. Decoding
  3. Executing
  4. Writeback
57
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Where is a CPU found in a furnace ?

A

It is in the Electronic Circuit Board

58
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Where are High Pressure Switches (HPS) found in a heating/cooling system ?

A

Located in the tubing between the discaharge side of the compressor and the condensing coil 9 in furnace.

59
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

What is the purpose of a Low Pressure Switch (LPS) in refrigeration ?

A

Monitors the refrigeration system for a loss of charge.

Also, Helps preventing the indoor coil from freezing up, due to dirty filter or low airflow over the indoor coil.

60
Q

SYSTEM CONTROLS AND SCHEMATICS 110305b

Concerning refrigration, How are (HPS) high pressure switch and ((LPS) low pressure switch reset once tripped ?

A

Manually

Either in the unit or by turning themostat OFF.

61
Q

FURNACE START-UP 110305c

It is considered safe practice to inspect the electrical connections with the power turned on

TRUE or FALSE

A

FALSE

62
Q

FURNACE START-UP 110305c

A typical circuit board on any furnace will have only one voltage.

TRUE or FALSE

A

FALSE

63
Q

FURNACE START-UP 110305c

What should be checked on the blower assembly when performing the start-up?

A

Confirm that all the shipping blocks or brackets have been removed. The wheel inside the housing should be checked to make sure that it is running on the center of the housing and that it is properly to the shaft of the motor.

64
Q

FURNACE START-UP 110305c

List the 3 acceptable methods to check for gas leaks.

A
  1. Test Dial
  2. Commercial Leak Detector
  3. Electronic Leak Detector
65
Q

FURNACE START-UP 110305c

WHich direction must the venting on the furnace slope ?

A

Upward and away from the furnace.

66
Q

FURNACE START-UP 110305c

What is the maximum distance the supports can be apart on system 636 venting ?

A

5 feet max

67
Q

FURNACE START-UP 110305c

What should you be looking for when checking duct connections ?

A

You should look for openings and gaps that might cause excessive leaking.

68
Q

FURNACE START-UP 110305c

What should the heat anticipator setting match ?

A

The amperage draw of the 24-volt circuit.

69
Q

FURNACE START-UP 110305c

What are the reasons for setting the manifold pressure.

A

Setting the manifold pressure is a critical adjustment that is made not only to ensure that the appliance is not over firing, but can be used to de-rate the appliance.

70
Q

FURNACE START-UP 110305c

What are the formulas for conveting gas quanty into Btuh ?

A
  1. Hourly Consumption = size of test dial X 3600
    sec. for 1 revolution of test dial
  2. Btuh = Hr Consumtion X Calorific Value of the Gas
71
Q

FURNACE START-UP 110305c

What are the Calorific Values for Natural Gas and Propane gas ?

A

Natural Gas 1000/ft2

Propane Gas 2500/ft2

72
Q

FURNACE START-UP 110305c

How is temperature rise calculated ?

A

The difference of return air temperature and the supply air temperature.

73
Q

When do the Blower Speeds have to be changed ?

A

The Blower Speeds have to be changed if the Temperature Rise is too low or too high.

74
Q

TESTING AND TROUBLESHOOTING

What 3 items does a combustion analyser when testing efficiency?

A
  1. CO2
  2. O2
  3. Excess Air
75
Q

TESTING AND TROUBLESHOOTING

What is a Draft Gauge used for?

A

To measure flue draft and pressure drop across air filters.

76
Q

TESTING AND TROUBLESHOOTING

List 4 types of efficiencies.

A
  1. Combustion
  2. Steady State
  3. Thermal
  4. Annual Fuel Utilization
77
Q

TESTING AND TROUBLESHOOTING

Define : Annual Fuel Utilization Efficiency

A

It measures the amount of heat actually delivered to the enclosure, compared to the amount of fuel that you must supply to the appliance in a season.

It also takes into account the cycle losses and associated energy losses of the heating unit as it responds to change in the load, which, in turn, is affected bychanges in weather and operator controls.

78
Q

TESTING AND TROUBLESHOOTING

Which dial is used for the purpose of clocking the meter?

  1. Test Dial
  2. Proving Dial
  3. X 100 Dial
  4. X1000 Dial
A
  1. Proving Dial
79
Q

TESTING AND TROUBLESHOOTING

What is the formula for calculating BTUH after clocking the meter?

A

Btuh = (volume test dial X 3600 / time 1 revolution) calorific value

80
Q

TESTING AND TROUBLESHOOTING

What is the calorific value of Natural Gas?

A

1000 BTU

81
Q

TESTING AND TROUBLESHOOTING

List the conditions that could possibly cause low O2 in the flue gas.

A
  1. Insufficient combustion air
  2. Burning over firing
  3. Low vent (stack) draft
82
Q

TESTING AND TROUBLESHOOTING

Lst 3 conditions that may cause low vent draft in an appliance.

A
  1. Improperly sized vent
  2. Vent system blocked
  3. Poor workmanship
83
Q

TESTING AND TROUBLESHOOTING

The LED on the PCB can be used to aid in the diagnosis of a fault in a furnace.

TRUE or FALSE

A

TRUE

84
Q

TESTING AND TROUBLESHOOTING

Every manufacturer uses LED fault codes on their PCB.

TRUE or FALSE

A

TRUE

85
Q

TESTING AND TROUBLESHOOTING

You should turn off the power to the appliance before you read the fault code.

TRUE or FALSE

A

FALSE

86
Q

TESTING AND TROUBLESHOOTING

List the 4 possible causes for a pressure switch not closing.

A
  1. Blocked vent pipe
  2. Damaged tubing from the induced draft assembly to the pressure switch
  3. Faulty inducer motor
  4. Dirty or worn inducer draft fan wheel
87
Q

TESTING AND TROUBLESHOOTING

List the 5 possible causes for a limit switch to open.

A
  1. Plugged filter
  2. Restriction in the duct work
  3. Loose blower
  4. Faulty blower motor
  5. Faulty switch or electrical connection
88
Q

TESTING AND TROUBLESHOOTING

Where is the Rollout Switch located?

A

Beside the Burner

89
Q

TESTING AND TROUBLESHOOTING

A Flame Sensor is checked by measuring the amount of what flowing through it?

A

DC microamps

90
Q

TESTING AND TROUBLESHOOTING

All HSI are supplied with 110volts.

TRUE or FALSE

A

FALSE

Some are 240 volt

91
Q

TESTING AND TROUBLESHOOTING

Having an oversized furnace can shorten the life of an HSI.

TRUE or FALSE

A

TRUE

Excessive temperature will wear out the HSI

92
Q

TESTING AND TROUBLESHOOTING

The troubleshooting procedure for a direct drive multi-speed motor is exactly the same as it is electronically commuted motor.

TRUE or FALSE

A

FALSE

93
Q

AIR BALANCING

Air velometer can measure airflow in cfm directly from any diffuser, grill or register.

TRUE or FALSE

A

FALSE

Holes are drilled into duct to insert probe.

94
Q

AIR BALANCING

What is the maximum static pressure that a velometer?

A

10” W.C.

95
Q

AIR BALANCING

When performing a rectangular duct traverse, the duct cross-section must be divided into a number of equal sections and the reading should be taken at the _____ of each of the sections.

  1. Right
  2. Left
  3. Centre
  4. Bottom
A
  1. Centre
96
Q

AIR BALANCING

What is the minimum number of readings that should be taken when performing a rectangular duct traverse?

A

12 readings is the minimum

97
Q

AIR BALANCING

What is the formula for corverting fpm to cfm on retangular duct?

A

The average fpm readings multiplied by the square footage of the duct.

98
Q

AIR BALANCING

A round duct traverse is performed using the same method as the rectangular duct traverse.

TRUE or FALSE

A

FALSE

99
Q

AIR BALANCING

AK factor are the same for all types of diffusers, grills or registers.

TRUE or FALSE

A

FALSE

100
Q

AIR BALANCING

When balancing a HVAC system, you must star with all the dampers in what position?

A

All dampers MUST be in fully open positon.

101
Q

What is the correct formula for calculating percent of design?

A

Preliminary cfm divided by Design cfm

102
Q

AIR BALANCING

The first outlet to be adjusted is the outlet with the what percent of design pressure?

A

The second lowest percent of design.

103
Q

AIR BALANCING

To convert fpm to cfm at a diffuser, grill or register, you would use the formula?

A

cfm = AK x fpm

104
Q
A

Sheet Metal 4th Yr (5 decks)

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