Chapter 7 Boiler Feedwater Controls

Question 1

1. Low water fuel cut-off devices require regular attention, the following intervals are recommended:
2. Once per shift
3. Daily
4. Weekly
5. Monthly
6. No attention is required

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

Answer 1

B. 2, 3, 4

Question 2

2. In a building heating system the condensate in the condensate receiver tank comes from the: 
A. Boiler feedwater 
B. Economizer 
C. Heating system 
D. Make-up water supply 
E. Deaerator

Answer 2

C. Heating system

Question 3

3. A second source of feedwater may be controlled by the:

A. Feedwater control switch 
B. Boiler operating control 
C. Boiler drum level control 
D. Low water fuel cut-off device 
E. Automatic blowdown device

Answer 3

D. Low water fuel cut-off device

Question 4

4.At normal boiler steaming rates, a condensate receiver tank should contain a sufficient volume of water equivalent to the water evaporated by the boiler for a maximum period of \_\_\_\_minutes. 
A. 15 
B. 20 
C. 30 
D. 45 
E. 60

Answer 4

C. 30

Question 5

5.The low water level fuel cut-off will shut off the fuel to the heating boiler when the water level drops below:
A. One half of the gauge glass
B. 50 mm (2 in.) above the bottom of the gauge glass
C. The lowest permissible water level
D. 25 mm (1 in.) above the bottom of the gauge glass
E. The lowest visible part of the gauge glass

Answer 5

E. The lowest visible part of the gauge glass

Question 6

6. Possible “causes of low water level” include:
7. Leaks caused by breakage or corrosion
8. Excessive blowdown
9. Automatic feedwater valve passing
10. Boiler feed pump failure
11. Excessive make-up

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

Answer 6

D. 1, 2, 4

Note: Leaks,Excessive Blowdown,Pump Failure

Question 7

7. “Make-up water” for the heating system usually comes from the:

A. Returning condensate 
B. Deaerator 
C. Boiler feedwater 
D. City water supply 
E. Boiler feedwater pump

Answer 7

D. City water supply

Note: Also other name FEEDWATER

Question 8

8. The main cause of heating boiler failure is overheating of the heating surfaces due to:

A. Low water conditions 
B. High firing rates 
C. Scale build-up 
D. High water conditions 
E. Low steam conditions

Answer 8

A. Low water conditions

Question 9

9. The float in the low water fuel cut-off will activate:

A. A globe valve 
B. A gate valve 
C. An electrical switch 
D. A solenoid valve 
E. An electrical relay

Answer 9

C. An electrical switch

Question 10

10. The low water fuel cut-off float is commonly used to operate both the Low water fuel cut-off switch and the:

A. High steam pressure switch 
B. Low fuel gas pressure switch 
C. Feedwater control switch 
D. Low steam pressure alarm 
E. Low feedwater temperature alarm

Answer 10

C. Feedwater CONTROL SWITCH

Question 11

11. The “float” operated low water fuel cut-off works on the principle of:

A. Differential pressure 
B. Buoyancy 
C. Temperature change 
D. Drum level variation 
E. Steam density

Answer 11

B. Buoyancy