floor may need repairing. The procedure for this repair
is as follows:
Figure 2-17.Removing expand able plug from economizer
plug from turning, as you tighten the nut. As you
tighten the nut using an open-end wrench or a socket
wrench, the gaskets expand radially, as they are
The removal of an expandable plug is shown in
figure 2-17. Insert a socket wrench or an open-end
wrench through the handhole and remove the retainer
nut. Insert the economizer plug extractor and then
thread it onto the retainer. Place the handhole plate
binder in position over the extractor and the thread on
the handhole fitting nut. As you tighten the nut, the
plug pulls out.
What five items of information are generally
required on boiler tubes?
When tubes on a boiler drum or header made of
4-6 choromium steel are removed what method
of removal cannot be used?
When tubes are fitted, tubes up to 2-inch-outside
diameter should project how far into the drum or
Tubes 2 inches or larger should be belled
between what size range?
What should you do to a plugged boiler tube to
avoid pressure buildup in the tube when the
boiler is operating?
REPAIRING BOILER REFRACTORIES
Learning Objective: Recognize maintenance and
repair procedures for boiler refractories.
Furnaces are built with high-grade, fire-resistant
materials that take a lot of punishment. Sooner or later,
however, repairs become necessary. Furnace walls or
First, mix the mortar, using a Navy-recommended fire
clay or fire cement and fresh water. Do not add anything
else. Make the mortar rather thin and without lumps.
Inspect the bricks for flaws and evenness. Choose
the best edge for the furnace side. Dip the brick in fresh
water and allow the excess water to drip off.
Now, dip one end and side of the brick into the
mortar, using an edgewise motion to prevent air
bubbles from forming. Lift the brick from the mortar
and allow the excess mortar to drip off. Do not place
any mortar on the wall or brick with a trowel.-The
mortar sticking to the brick is all that is used.
If the mortar is too thick, you will not get the thin
joints that you want. The mortar should be a little
thinner than the usual wall plaster. You can feel the
proper thickness with your hand. Some mortar will
stick to your hand, as you lift it away from the mortar.
Add more clay or water as necessary, and stir the batch
often to keep the mortar at the desired consistency.
Place the brick quickly in position in the wall and
pound it in place with a wooden mallet until no mortar can
be forced out of the joints. With high-grade brick, joints
can be made less than one thirty-second of an inch thick.
Joints should never exceed one-sixteenth of an inch.
With a small trowel, fill in any unevenness in the
furnace side of the seam and bead over the joints, as
shown in figure 2-18. Be sure that no edges of the brick
are exposed. The wall should be laid up evenly and
smoothly. Any excess mortar that protrudes from the
joints should be smoothed off with a small trowel, so
the corners of the brick are protected.
Allow the wall to dry for about 12 hours with the
burner shutters open to allow circulation of air, which
permits the escape of some of the water added to the
mortar. As soon thereafter as practicable, light the
burner under the boiler and slowly bring the furnace up
to operating temperature to bond the mortar to the
Figure 2-18.Cementing brick.