Electronic Ignition, Furnace Start Up, System Controls And Schematics

Question 1

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

Answer 1

The direct ignition gas valve has no pilot connection

Question 2

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

Answer 2

Flame rectification

Question 3

What is the minimum flame rod to ground electrode area ratio that is immersed in the flame

Answer 3

1:4

Question 4

Why have flame conductivity systems not been used for proving flame

Answer 4

The system will not distinguish between a flame and a short to ground

Question 5

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

Answer 5

Call for heat at the thermostat

Question 6

What is the importance of the connection diagram

Answer 6

It shows where the wires go and the colour of the wires

Question 7

What is the importance of the ladder diagram

Answer 7

It shows how the appliance works for troubleshooting

Question 8

List five parts of a relay

Answer 8

Coil
Core
Return spring
Armature
Contacts

Question 9

List the four most common arrangements for the contacts of a relay

Answer 9

SPST NO

SPST NC

SPDT

DPDT

Question 10

Name the two most common capacitors

Answer 10

START

RUN

Question 11

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

Answer 11

Dielectric

Question 12

What activates the pressure switch

Answer 12

Inducer Motor

Question 13

What is flame rectification

Answer 13

Process of proving flame

Question 14

Where is the CPU located

Answer 14

Control board

Question 15

In a cooling unit where is the high pressure switch located

Answer 15

Tubing between the discharge side and the condensing coil of the unit

Question 16

Explain the function of a low pressure switch

Answer 16

Monitors refridgeration system

Question 17

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

T or F

Answer 17

False

Question 18

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

T or F

Answer 18

False

Question 19

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

Answer 19

Alignment
Secured to shaft
Shipping blocks/brackets removed

Question 20

List 3 acceptable methods to check for gas leaks

Answer 20

Test Dial
Leak detector
Electronic leak detector (sniffer)

Question 21

Which direction must venting on the furnace slope

Answer 21

Upwards and away from the furnace

Question 22

What is the maximum distance between supports on 636 venting

Answer 22

5 feet

Question 23

What should you be looking for when checking duct connections

Answer 23

Openings/gaps

Question 24

What should the heat anticipator setting match

Answer 24

Amperage draw of the 24 volt circuit

Question 25

What are the reasons for setting manifold pressure

Answer 25

To ensure appliance is not overfiring Can be used to de rate the appliance

Question 26

What are the calorific values for natural gas and propane

Answer 26

1000 2500

Question 27

How is temperature rise calculated

Answer 27

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

Question 28

When do the blower speeds have to be changed

Answer 28

If the temperature rise is too low or too high

Question 29

What is dsi

Answer 29

DIRECT SPARK IGNITION

Question 30

What is IP

Answer 30

Intermittent pilot

Question 31

What is HSI

Answer 31

Hot surface igniter

Question 32

How is an ignition system energized

Answer 32

By the ignition module or PCB

Question 33

An automatic ignition system uses what flame sensing device

Answer 33

A flame rod

Question 34

List the components that can be found in a direct spark ignition system.

Answer 34

The ignition module, The ignitor, the flame rod, the wiring, the gas valve.

Question 35

Provide the usual voltage for a system control module.

Answer 35

24 volts

Question 36

A system control module provides what functions

Answer 36

Energizes the pilot valve and main valve, lights the pilot or main burner, proves the flame, monitors the flame, de-energizes the gas valve.

Question 37

What gas control valve is used on a DSI, IP and HSI?

Answer 37

A combination gas valve

Question 38

A redundant gas valve can provide protection against what?

Answer 38

The main operator failing in the open position

Question 39

Which ignition system energizes only the first main valve to open and allow gas to flow to the pilot?

Answer 39

Direct ignition

Question 40

The function of a flame sensor is?

Answer 40

To prove there is a flame present

Question 41

A flame sensor rectifies a AC signal to a microamp DC current. T or F

Answer 41

True

Question 42

On a spark ignition system the gap between the igniter sensor and grounding strap should be?

Answer 42

1/8”

Question 43

What is meant by system pre-purge?

Answer 43

The inducer motor runs to clear out the vent of products of combustion.

Question 44

What is meant by trial for ignition?

Answer 44

The time it takes to light the main burner and prove there is a flame present.

Question 45

What is meant by retry for ignition?

Answer 45

The system will try again to light the main burners and prove a flame.

Question 46

What is meant by system lockout?

Answer 46

After one or multiple attempts to light the burners fails. The system will “lockout”

Question 47

What are two things that can be done to reset lockout?

Answer 47

Turn off the main power or turn off the call for heat at the T-Stat.