100-123

Question 1

100.How can you determine if a water gauge glass is properly set? SPO 6-7-8

Answer 1

By filing the boiler with water to normal operating level and measuring the depth of the water to the top row of tubes.

Question 2

101.How high above the top row of tubes in an H.R.T. boiler must the lower gauge cock be set to have a safe amount of water at this point? SPO 6-7-8

Answer 2

At least 3” above the top row of tubes.

Question 3

102.Name three appliances that can warn you of low water. SPO 6-7-8

Answer 3

Water sight glass
Low water alarm
Fusible plug

Question 4

103.If your boiler has only one low water cutoff what is the ASME code requirement? LPB 2-3

Answer 4

That it must have a manual reset.(Side Note: The City of Omaha requires one to be a manual reset even if you have 2 cutoffs. If there is repair work done on the boiler there must be a manual reset added)

Question 5

104.What is the purpose of a high fire limit control on a boiler? What is a modulating control? BOW 2-3-4

Answer 5

It proves that the forced air damper has fully opened prior to starting the pre-purge period to insure adequate purge air flow.
It adjusts the firing rate of the burner to maintain the boiler steam pressure.

Question 6

105.Is an automatic shutoff allowed between the boiler and the water column? SPO 6-7-8

Answer 6

NO! Only between the water column and the gauge glass.

Question 7

106.What type valves are allowed between the boiler and the water column? SPO 6-7-8 BOW 2-3-4

Answer 7

ONLY O.S. & Y. or Stopcocks which are locked or sealed open!

Outside screw and yoke

Question 8

107.Name two types of fusible plugs. SPO 6-7 LPB 2-3 BOW 2-3-4

Answer 8

FIRESIDE & WATERSIDE. This refers to the side where they are installed.

Question 9

108.What is a bourdon tube? SPO 6-7-8 LPB 2-3 BOW 2-3-4

Answer 9

The Bourdon tube consists of a curved tube with an oval cross section. One end is attached to the frame and pressure connection. The other end is attached to a pointer, linkage and gears. An increase in pressure tends to straighten the tube; its motion is transmitted to the pointer.

Question 10

109.What is a siphon tube and what is it used for? SPO 6-7-8 LPB 2-3 BOW 2-3-4

Answer 10

A siphon tube or pigtail loop protects the mechanism of the gauge from live steam

Question 11

110.What pressure range should a steam gauge be when used on a boiler? SPO 6-7-8 LPB 2-3 BOW 2-34

Answer 11

It should be a compound gauge at least 1½ times the maximum allowable working pressure.

Question 12

111.Where is the steam gauge connected to the boiler? How do you properly mount a steam gauge to a boiler? SPO 6-7-8-LPB 2-3 BOW 2-3-4

Answer 12

It is mounted either on top of the water column or to the top of the steam drum.
A gauge is mounted with a siphon tube, isolation valve and test connection.

Question 13

112. Name three types of feedwater regulator systems. SPO 6-7-8 BOW 244

Answer 13

1. MODULATING such as thermohydrolic or thermodynamic.
2. ON/OFF, Such as a float probe.
3. METERING as a 2 or 3 element.

Question 14

113.Why is a boiler feed pump used on some boilers and not others

Answer 14

You will not need a pump if the operating pressure of the boiler is below city water pressure.

Question 15

114.What is the most important valve on a boiler? SPO 6-7-8 LPB 2-3 BOW 2-3-4

Answer 15

The SAFETY valve.

Question 16

115.What is a safety valve and how does it operate? SPO 6-7-8 LPB 2-3 BOW 2-3-4

Answer 16

It is a device to expel all excess steam pressure from a boiler. The huddling chamber causes the valve to open fully and quickly, causing a definite drop in pressure before closing.

Question 17

116.A safety valve is limited to how many square feet of heating surface? SPO 6-7-8 LPB 2-3 BOW 2-3-4

Answer 17

Any boiler with more than 500 sq. ft. of heating surface must have 2 or more safety valves.

Question 18

117.If a safety valve lifts at 100 psi what pressure should it close? What are the requirements governing safety valve blowdown? SPO 6-7-8 BOW 2-3-4

Answer 18

96 to 98 PSI

Safety valve shall operate without chattering, with a blow down of not more than 4% of the set pressure and in no case, less than 2 pounds.

Question 19

118.How do you determine if a boiler has sufficient safety valve capacity? SPO 6-7-8 LPB 2-3 BOW 2-34

Answer 19

The ACCUMULATED test determines if the valves will discharge all the steam generated by the boiler without allowing the pressure to rise more than 6% above the maximum allowable working pressure of the boiler.

Question 20

119.How must a safety valve be connected to the boiler? SPO 6-7-8

Answer 20

1. Independent of any other steam connection.
2. Close as possible without any unnecessary piping.
3. Screwed into the boiler shell or fastened to a flange welded to the shell.
4. Connected to stand upright.
5. Vents must be fastened to the building and not connected to the valve.

Question 21

120.At what temperature does a safety valve on a superheater have to be protected with heat resisting materials? SPO 6-7-8

Answer 21

450 degrees F.

Question 22

121.How do you regulate the blowdown of a safety valve? SPO 6-7-8 LPB 2-3 BOW 2-34

Answer 22

The blowdown is adjusted by adjusting the blowback ring, the spring or both about 10%. Only trained and licensed personnel should adjust safety valves.

Question 23

122.How often is it recommended to test your safety valves manually and how often under pressure? BOW 2-3-4

Answer 23

Every 30 days manually and Yearly under pressure

Question 24

123.How is a superheater protected? SPO 6-7-8 BOW 2-34

Answer 24

Each Superheater must have one or more safety valves near their outlet with the pressure set below those on the boiler insuring a constant flow of steam through the Superheater.