2-41. What temperature is required to bake
out plastic refractory?
1. 1000°F to 1200°F
2. 1500°F to 1700°F
3. 2000°F to 2200°F
4. 2900°F to 3000°F
2-42. You should NOT use high-
temperature bonding and an air-dry
type of mortar, diluted with water to
the consistency of light cream, for
patching when bricks fall out.
2-43. After removing all the old refractory
and foreign material, you should
inspect the furnace metal for which of
the following conditions?
4. Heat cracks
2-44. Before installing tiles, you should take
1. Preheat the tiles
2. Wash the tiles
3. Dry fit and match mark the tiles
4. Coat the sealing area with an
insulating pulp cement
2-45. It is normal for refractories exposed to
hot gases to develop thin, hairline
cracks. What size does a crack have to
be before you clean and fill it with
high-temperature bonding mortar?
1. Between 1/16 to 1/8 inch
2. Between 1/8 to 1/4 inch
3. Between 1/4 to 3/8 inch
4. Between 3/8 to 1/2 inch
2-46. After inspecting the door head gasket,
you should coat the gasket with which
of the following types of mixtures?
1. Gasket cement mix
2. Vee block mixture
3. Wash coat mixture
4. Oil and graphite mixture
2-47. When replacing the door gasket, you
should use what size rope gasket?
1. 1 1/4 inches
2. 1 1/2 inches
3. 1 3/4 inches
4. 2 1/4 inches
2-48. There are seven major phases in the
operation of a boiler.
2-49. Which of the following actions is
NOT required by a oncoming watch
1. Test the water columns and gauges
2. Inspect the fans, damper, and
3. Test fire the furnace
4. Visually inspect the setting and