circuit component

Question 1

What is an operating control?

Answer 1

An operating control turns the burner
system on and off based on the desired
pressure or temperature for the system

Question 2

• Interlocks specific to burner operation
  are categorized as:

Answer 2

Fuel valve end switch interlocks
* Purge interlocks
* Running interlocks
* Low fire start interlocks

Question 3

How low fire interlock is proven?

Answer 3

Generally a firing rate motor linkage
position switch or a damper position
switch, will prove both the linkage and
dampers are in their proper positions to
begin burner light off.

Question 4

What percentage is considered low fire ?

Answer 4

B149.3 - Definitions
Low fire start — the initial ignition of the
main flame at an input of 40% or less of
the rated maximum input.

Question 5

define Control Circuit ?

Answer 5

Control Circuit – the circuit that carries the electrical
signals directing the performance of a control device, but
does not carry the power that the device controls.

The Control Circuit is often called the Limit Circuit or the
Safety Limit Control Circuit (B149.3-20).

Question 6

What are non-recycling interlocks?

Answer 6

Many Interlocks incorporate a lockout / manual reset function.
They are called Non-recycling interlocks because they will need
manually reset to resume operation.

Question 7

Define permissive and interlock?

Answer 7

PERMISSIVE: conditions that need to be satisfied
before you can start the equipment cycle
INTERLOCK: prevents an appliance from damaging
itself if a condition fails to be satisfied.

Question 8

What are run Interlock

Answer 8

Prove conditions critical to combustion (typically fuel & air)

Question 9

what kind of interlock are these?
* Combustion Air Proving Switch (CAPS)
* Mag Starter Aux Switch
* Low gas Pressure Switch (LGPS)
* High Gas Pressure Switch (HGPS)
* Oil Temp Switch
* Low Oil Pressure Switch
* Low Atomizing Media Switch

Answer 9

RUN INTERLOCK

Question 10

WHAT IS THE VOLUME AND INPUT % REQUIREMENT FOR PRE-PURGE?

Answer 10

This purge period shall
provide at least four air changes of the combustion zone and flue passages.
The airflow rate during the purge shall be not less than 60% of that
required for maximum input, unless a lower airflow rate is required to
prevent hazardous conditions.

Question 11

Purge interlocks are ?

Answer 11

*Purge Switch
* High Fire Switch
* High Fire Interlock
* High Fire Proving Switch
* High Purge Proving Switch

Question 12

Preignition Interlock

Answer 12

• Start Interlock
• Fuel Valve Switch
• Proof of Closure Switch
• Overtravel Proof of Closure Switch

Question 13

What is the standard voltage used for industrial control circuitry?

Answer 13

120v

Question 14

Why are separate ignition transformers used for industrial burner systems?

Answer 14

To generate a big and hot enough spark to ensure the fuel ignites quickly and efficiently

Question 15

Are limit circuits wired in parallel or series?

Answer 15

series

Question 16

List four specific conditions that a limit in a circuit control can control for?

Answer 16

Temperature, Pressure, Liquid Level and Liquid Flow

Question 17

What are the two types of reset for limit switches

Answer 17

automatic and manual

Question 18

What does an operating control do and what are the two most common limits associated with them?

Answer 18

An operating control turns the burner system on and off based on temperature or pressure.

Question 19

What is one purpose of a permissive circuit?

Answer 19

To ensure two incompatible events don’t occur at the same time.

Question 20

Define an interlock:

Answer 20

An interlock is a feature that makes the state of two mechanisms or functions mutually dependent (one can’t work without the other).

Question 21

A DFMAH shall be ______ in such a way as to prevent its operation unless the exhaust system is functioning.

Answer 21

Interlocked

Question 22

What must be proved when using automatically operated louvres for the inlet and discharge of a DFMA?

Answer 22

They must be proved fully open.

Question 23

What is the purpose of a purge interlock?

Answer 23

To prove that the purge air flow rate is at maximum during the purge

Question 24

An airflow switch is an example of what type of interlock.

Answer 24

Running interlock

Question 25

The low fire start interlock permits the ignition of the pilot of main flame at an input of:

Answer 25

40% or less of the rated maximum input