305A/305B/305C

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 the flame called?

Answer 2

Flame rectification

Question 3

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

Answer 3

1:4

Question 4

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

Answer 4

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

Question 5

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

Answer 5

Call for heat

Question 6

What’s the importance of the connection diagram?

Answer 6

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

Question 7

What is the importance of a ladder diagram?

Answer 7

Shows how the appliance works for troubleshooting

Question 8

What device has a capacitor connected to it?

Answer 8

Blower motor

Question 9

Two main principles in Flame rod detection systems are?

Answer 9

Flame rectification
Flame conductivity

Question 10

In conductivity systems the ground electrode must be at least ____ times that of the flame rod?

Answer 10

4 times
4:1 ratio

Question 11

Flame rectification is measured in what

Answer 11

DC micro amps

Question 12

What is the spark gap on an Intermittent pilot spark ignition system?

Answer 12

1/8” gap

Question 13

What’s the difference between intermittent pilot ignition and an interrupted pilot ignition system?

Answer 13

In Intermittent pilot system the pilot is not extinguished after ignition of the main burner

Question 14

What are the different types of electronic ignition systems?

Answer 14

Intermittent pilot using spark
Intermittent pilot using Hot surface
Direct ignition using spark
Direct ignition using hot surface

Question 15

What is DSI?

Answer 15

Direct spark ignition

Question 16

What is IP

Answer 16

Intermittent pilot ignition

Question 17

What is HSI?

Answer 17

Hot surface ignition

Question 18

An automatic ignition system uses what for a flame sensing device?

Answer 18

Flame rod/ flame rectification

Question 19

What is the igniter on a HSI made of typically?

Answer 19

Silicon carbide

Question 20

What happens when lockout occurs?

Answer 20

De energizes spark ignition and burners

Question 21

Adjustable components in a mid efficiency furnace?

Answer 21

Blower fan off time delay
Blower fan speeds

Question 22

List 5 parts of a relay

Answer 22

Coil
Core
Return spring
Armature
Contacts

Question 23

4 common arrangements for the contacts of a relay

Answer 23

SPST-NO - Single Pull Single Throw Normally Open
SPST- NC - Single pull Single throw Normally Closed
SPDT- Single pull Double Throw
DPDT- Double Pull Double Throw

Question 24

2 Types of capacitors?

Answer 24

Run Capacitors
Start Capacitors

Question 25

Material used to seperate 2 plates in a capacitor?

Answer 25

Dielectric

Question 26

What activates the Pressure Switch?

Answer 26

Pressure switch is activated when the IDM starts turning and creates enough pressure

Question 27

What is flame rectification?

Answer 27

It is an AC electrical circuit that sends a small current from the furnace board to the flame rod. When the flame is established the flame acts as a conductor or path which allows current to flow across from the flame rod to ground burner completing the circuit

Question 28

Where is the CPU located?

Answer 28

Control board

Question 29

What way is a ladder diagram read?

Answer 29

Left to right

Question 30

What’s HPS stand for

Answer 30

High Pressure Switch

Question 31

What’s LPS

Answer 31

Low Pressure Switch

Question 32

What is a better HSI? Silicone carbide or silicone Nitride?

Answer 32

Silicone Nitride

Question 33

What commonly use Run Capacitors?

Answer 33

Air handler blower motors, Induced or forced draft fan motors on high efficiency furnaces, condenser fan motors, compressors and pumps for hot water and chilled water

Question 34

Common applications for Start capacitors?

Answer 34

Typically only used to start compressors

Question 35

Voltage classification for Run Capacitors?

Answer 35

370V and 440V

Question 36

Voltage classification for Start capacitors?

Answer 36

125V, 250V and 330V

Question 37

Is it safe to inspect electrical components with the power on?

Answer 37

No

Question 38

Typical circuit board on any furnace will only have one voltage ?

Answer 38

False

Question 39

List 3 acceptable methods to check for gas leaks ?

Answer 39

Test dial Commercial leak detectors Electronic leak detector

Question 40

What direction must venting on the furnace slope?

Answer 40

Upwards and away from the furnace

Question 41

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

Answer 41

5 Feet

Question 42

What should the heat anticipator be set to?

Answer 42

The amperage draw of the 24-volt circuit

Question 43

Formulas for converting gas quantity into BTUh?

Answer 43

Hourly consumption =( size of test dial / # secs. 1 revolution) x 3600 BTUh = hourly consumption x calorific value

Question 44

How is an ignition system energized?

Answer 44

Ignition module

Question 45

What is the usual voltage for a system control module?

Answer 45

24V

Question 46

What gas control valve is used for DIS, IP and HIS?

Answer 46

Combination Gas Valve

Question 47

A redundant gas valve can provide protection against what?

Answer 47

The main operator failing in the open position

Question 48

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

Answer 48

Direct ignition

Question 49

What’s the function of a flame sensor?

Answer 49

To prove there is a flame

Question 50

A flame sensor rectifies a AC signal to a _________________

Answer 50

Micro Amp DC current

Question 51

What does a system pre purge mean?

Answer 51

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

Question 52

What does trip ignition mean ?

Answer 52

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

Question 53

What does lockout mean?

Answer 53

After 1 or multiple attempts to light the burners and it fails system will go into lockout.

Question 54

What are 2 things that can be done to reset Lockout?

Answer 54

Turn off main power or turn off call for heat @ TSTAT

Question 55

How should Venting be installed?

Answer 55

Venting shall be installed with no dips or sags