Fourth Year Gas Electrical Circuits And Controls For Commercial Gas Appliances

Front 1

Voltage is electric pressure. It is similar to psi in a gas line.

What is the scientific name for voltage and what letter is used to identify it?

Back 1

Electromotive Force

E

Front 2

Amperage is the flow of electrons. It is similar to gallons per minute or litres per second of flow in a pipe.

What is another word to describe amperage and what letter is used to identify it?

Back 2

Induced current

I

Front 3

An Ohm is the resistance of a wire or circuit to flow. What happens when there is a higher resistance to flow? What letter identifies resistance in Ohms?

Back 3

Less flow

R

Front 4

Ohms law paradigm

Back 4

E

I. R

Front 5

In Watts Law, Volt Amps = Watts( W) or Power

Voltage = E or V

Amperage equals I or A.

There are two watts different ways to identify a Watts Law paradigm.

Remember, Watts was a baker

Back 5

W (watts).

A( Amps) V ( voltage)

Or

P ( Power)

I ( Amps) E ( voltage)

Front 6

Watts Law states that apparent power (P)is equal to voltage X amperage.

P = V X A

Voltage x Amperage = VA ( volt amps)

The Maximum Amperage can be determined by dividing the VA rating by the voltage supplied to the circuit.

If a 24 volt transformer has a rating of 40 VA, what is the maximum output in amps?

Back 6

40va / 24v = 1.6 Amps

Front 7

The 3 devices needed to make a circuit are ?

Back 7

A power source

A switch

A load ( consumer)

Front 8

A volt meter will display the difference between 2 leads

If the voltage in the read lead is 24 and the voltage on the black is 0 , what will the meter display?

Back 8

24

Front 9

How must a volt meter be connected?

Back 9

In parallel with the power on

Front 10

The Ohm meter will display the resistance of the circuit in OHMS. How must it be connected?

Back 10

In parallel with the power off

Leaving the power on may damage the meter.

Front 11

An amp meter will display the amount of current flowing through a circuit or device.

How must an amp meter be connected?

Back 11

In series with the power on.

Front 12

A clamp on an ammeter is connected by clamping around one wire . What will it read if you clamp around two wires?

Back 12

It will read zero

Front 13

If the amperage reading is too low to attain a proper reading, what must be done?

Back 13

Wrap the wire 10 times and insert into the jaws of the meter. Then take the reading and divide it by 10

Front 14

What does a continuity test prove?

Back 14

The existence of an electrical pathway

Front 15

When you are unsure of the voltage, amperage or resistance, where do you set the meter?

Back 15

On the highest setting , it can then be lowered

Front 16

Why does a digital meter flash OL?

Back 16

The meter scale has been exceeded and we need to use a higher scale.

Front 17

What two types of current are used on gas appliances?

Back 17

AC ( alternating current ) and DC ( direct current)

Front 18

When using a DC meter, where must the Red lead be connected?

Back 18

On the positive terminal.

AC power is not polarity sensitive

Front 19

A series circuit has one current pathway, a parallel circuit has two or more independent current pathways .

What are series/parallel and Series AND parallel circuits?

Back 19

Series/parallel the series portion controls the parallel portion

Seres and parallel the two circuits are independent of each other.

Front 20

This formula is for calculating the resistance of what circuit?

Rt= R1 + R2 + R3

Back 20

Series circuit

Front 21

What is the formula for calculating resistance in a parallel circuit?

Back 21

1/Rt= 1/R1 + 1/R2 +1/R3

Front 22

The total resistance of a series/parallel and a series AND parallel circuit is found by________

Back 22

Combining both formulas

Front 23

The total resistance of a series circuit will always be ______than the _______ resistor in the circuit.

Back 23

Higher

Highest

Front 24

The total resistance in a parallel circuit will always be ________ than the ________ resistor in the circuit.

Back 24

Lower

Lowest

Front 25

Kirchoffs amperage law states that the total amperage draw will always be what?

Back 25

The sum of the amperage draws through each leg of the circuit

Front 26

All wiring diagrams accompanying gas appliances are shown with the unit in ______

Back 26

Stand By

Front 27

Which type of diagram uses symbols and shows the rough geographic location of the controls and actual wiring as it appears in the appliance?

Back 27

Connection

Front 28

Which is the best diagram for trouble shooting?

Back 28

A ladder diagram. It uses symbols and shows how the unit works

Front 29

______ are wired into the circuit in series so that any one ______

Can shut off the system. ________ are not consumers.

Back 29

Switches

Switch

Switches

Front 30

Power consumers consume power and must be wired in parallel. What are 2 examples of power consumers?

Back 30

Gas valves and motors ( loads)

Front 31

The potential difference ( voltage) across an open switch ( off) would be equal to the voltage supplied to the circuit.

What would the potential difference in voltage be across an difference across an energized switch ( on) be?

Back 31

Zero

Front 32

What does a heat anticipator in a room thermostat do?

Back 32

Causes the switching mechanism to respond quicker , shutting off the forced air furnace to reduce or eliminate temperature overshoot.

Front 33

How does a diaphragm gas valve open or close?

Back 33

Gas pressure. It is slow to respond

Front 34

A solenoid gas valve reacts to a call from the operating control .

How fast does it respond ?

Back 34

Immediately

Front 35

A solenoid gas valve acts on magnetism. When the coil is energized it is energized by ______.

Back 35

A strong electro magnet that lifts the valve off its seat. An iron core is inserted into the coil to concentrate and intensify the magnetic field.

Front 36

A step down transformer is both a power consumer and power source.the primary coil is ______and consumes power. The secondary coil is ______ and is a power source.

Back 36

110 VAC

24 VAC

Front 37

How is electromotive force measured?

Back 37

Volts

Front 38

How is resistance measured

Back 38

Ohms

Front 39

How is electrical power measured?

Back 39

Watts ( P)

Front 40

What material is the best conductor?

Back 40

Copper

Front 41

What is the amp draw on a 120volt 60 watt lightbulb?

Back 41

P( 60 watts)

I ? E ( 120 Volts)

60/120 = 0.5 Amps

Front 42

How many loads in a series circuit for a gas fired appliance?

Back 42

1

Front 43

Why are parallel circuits used in the heating industry?

Back 43

To supply the same voltage to the loads

Front 44

What is the voltage supplied to four parallel circuits with a 120v power supply?

Back 44

120 volts

Front 45

What is the maximum high limit setting for a forced air conversion furnace?

Back 45

250F

Front 46

What will a poor ground in an ignition module cause?

Back 46

No main flame