4B Absa Exam Questions Flashcards
Machine bolts are commonly supplied with
Hexagon heads
Which is not found on the low side of an ammonia absorption refrigeration system
Generator
Bacteria can range from _______ in size
0.2 to 5 microns
A light fuel oil flame should
Be bright yellow, with orange at the tips of the flame
Soot should be removed from fire tube boiler tubes with
Wire brushes
The most widely used refrigerant metering device, which consists of a pressure-sensitive Bellows or diaphragm connected to a temperature sensing bulb, is the
Thermostatic expansion valve
For economic operation, the steam Supply to a steam engine is cut off once the Piston has travelled _______ of its stroke
1/4 to 1/3
ASME VII states that a high pressure steam plant comprised of a single power boiler may have it’s boiler and steam lines
Warmed up at the same time, or independent of each other
The instrument that measures the viscosity of an oil at a certain temperature as it flows through a small diameter tube, is called
A saybolt viscometer
The propeller axial-flow fan;
Find application in unit heaters, air-cooled condensers, and as an exhaust fan for ventilation purposes
Gas turbines are ideal where
Water is scarce
Natural draft cooling towers are divided into;
2
Atmospheric towers and chimney Towers
The most commonly used acid for boiler cleaning is
Hydrochloric acid
Occupancy sensors;
Are automatic switches
The raw natural gas from the wells, for use in a gas processing plant, is known as
Feedstock
The set pressure of a safety valve may only be adjusted by
The safety valve manufacturer, it’s authorized representative, or an assembler
Galvanic corrosion depends on
A difference in electrochemical potential between dissimilar metals
The output power of a gas turbine depends on
The mass of hot gas passing through the turbine per unit time
An essential auxiliary in a gas turbine installation is
A starting motor
The total or methyl alkalinity test indicates the alkalinity that is due to
All forms of alkalinity
Rotary pumps
Are positive displacement pumps
Which of the following has the greatest effect on the viscosity of lubrication oil
Temperature
If an oil must flow at a very low temperature, it must have the following additive
Pour Point depressant
In a circulating domestic hot water system, automatic air vents
Remove air that is released when water is heated
Infrared heaters are commonly installed to direct their heat output towards
Floors
It is good design practice to select a steam coil size so that
At least 40% of the coil capacity is needed when the air temperature entering the coil is -1°C
The kind of Grease used for heavily loaded Machinery operating at slow speeds is the
Specialty Grease
If a shutdown occurs during normal firing of a boiler and the steam pressure is below the normal cut out value, the problem could be
An interlock, such as the combustion air proving switch has failed
A deep seal Plumbing trap has a water seal depth of
10cm
The first step when repairing a faucet
Shut off the water at the nearest isolation valve
In an internally fired, gas-fired infrared heater, the surface temperature is about
400°C
A normal anti-friction bearing temperature operating range is
65 to 70°C
When the maximum building demand for potable water is always less than the maximum flow available from a municipal or local distribution system, which system can be used
Tankless constant pressure system
The final step when replacing a firetube
Hydrostatic test
The heat recovery system that uses a sealed tube, capillary Wick structure, and a refrigerant liquid, is called
Heat pipe
One of the ways to detect a fault in a reciprocating steam engine is by;
Monitoring changes in its sound
Which is not a type of centrifugal fan
Radial blade fan
Ladders that are used in the workplace should comply with
WCB regulations and CSA standards
In a circulating domestic hot water system, automatic air vents
Remove air that is released when water is heated
The _______ number of oil indicates the acidity of oil
Neutralization
A closed cycle gas turbine
Recycles the same working fluid
The characteristics of a grease are determined by
It’s thickening agent or soap
Most dimmer switches sold today
Are solid state devices
Smaller spark ignition engines use _______ to vaporize gasoline
Carburetors
A cold weather cooling tower bypass valve should not be fully closed until the temperature reaches
About 27°C
The combustion chamber of a gas turbine
Is where fuel is added to Air, and burned
If ambient air temperatures are very low, the preferred lubricant is a
Solid lubricant
