Book 1: 2-08 - Heating Boiler Operating Controls

Question 1

Damper position switches are found on boilers with the following burner control systems:
1. On-Off control
2. High- Low control
3. Modulating control
4. High Limit control

Select one:

A. 2,3
B. 1,2
C. 1,3
D. 3,4
E. 4,5

Answer 1

A. 2,3

Question 2

The high gas pressure cut-off switch can be tested by:

Select one:

A. Slowly closing the main gas valve
B. Slowly raising the boiler pressure above the operating setpoint
C. Closing the main gas valve quickly
D. Slowly covering the air supply to the fan
E. Quickly closing the main burner shut-off valve

Answer 2

E. Quickly closing the main burner shut-off valve

Question 3

The High-Low fire control method requires two pressure controllers, one is called the high-low fire control and the other is called the:

Select one:

A. Modulating fire control
B. High limit fire control
C. Operating limit fire pressure control
D. On-Off fire control
E. Operating limit fire control

Answer 3

C. Operating limit fire pressure control

Question 4

If the pressure of the gas supplied to the burner drops below a minimum value the _______ switch will de-energize the fuel valve.

Select one:

A. Low water level
B. Low air pressure
C. High gas pressure
D. High limit.
E. Low gas pressure

Answer 4

E. Low gas pressure

Question 5

The hot water heating boiler burner control uses the ______ as the sensed variable.

Select one:

A. Feed water pressure
B. Boiler steam temperature
C. Boiler water temperature
D. Drum water level
E. Boiler water pressure

Answer 5

C. Boiler water temperature

Question 6

The low air pressure cut-off switch can be tested by:

Select one:

A. Slowly covering the air supply to the fan
B. Slowly raising the boiler pressure above the operating set point
C. Slowly closing the main gas valve
D. Closing the main gas valve quickly
E. Quickly closing the main burner shut-off valve

Answer 6

A. Slowly covering the air supply to the fan

Question 7

An automatic/manual selector switch is provided on a boiler with the following burner control system.

Select one:

A. High-low fire control
B. On-Off fire control
C. Operating limit fire control
D. High limit fire control
E. Modulating fire control

Answer 7

E. Modulating fire control

Question 8

The high limit control of a steam heating boiler should operate at the:

Select one:

A. Set pressure of the safety valve
B. Cut-out pressure of the operating control
C. Maximum allowable working pressure
D. Between the set pressures of the operating control and safety valve
E. Blowdown pressure of the safety valve

Answer 8

D. Between the set pressures of the operating control and safety valve

Question 9

If the pressure of the gas supplied to the burner increases beyond the maximum required for safe combustion the _____ switch will de-energize the fuel valve.

Select one:

A. Low air pressure
B. Low water level
C. High gas pressure
D. Low gas pressure
E. High limit

Answer 9

C. High gas pressure

Question 10

The On-Off pressure controller contains two adjustable variables, one is the pressure adjustment and the other is the:

Select one:

A. Differential adjustment
B. Pressure bellows
C. Cut-in Lever
D. Levelling indicator
E. Operating lever

Answer 10

A. Differential adjustment