ABSA 4B EXAM | QUESTIONS AND ANSWERS | 2026 UPDATED | WITH COMPLETE SOLUTIONS

Sodium sulphite is a commonly used ____ in boilers. oxygen scavenger carbon dioxide scavenger coagulant pH inhibitor flocculant - CORRECT ANSWER-a Cement may be used for the protective coating of a ____. u-tube manometers orifice plates venturi tubes pressure gauges hot water storage tank - CORRECT ANSWER-e The hot exhaust gases from the gas turbine combustor travel downstream to be ____ in the turbine blading. expanded filtered heating contracted cooled - CORRECT ANSWER-a Recovery boilers must be shut down immediately when a tube leak develops because water generates a violent physical reaction upon contacting ____. white liquor black liquor green liquor molten smelt cooking liquor - CORRECT ANSWER-d In operating applications with high pressure and slow speed ____ are commonly used. coagulants light oils low viscosity mineral oilslow viscosity synthetic oils heavy oils - CORRECT ANSWER-e During the power stroke of a four-stroke engine, the ___ is combusted. lubricating oil hydrogen air fuel/air mixture fuel - CORRECT ANSWER-d ____ are small relief valves that do not relieve pressure but are installed in systems to warn of impending overpressurization. Rupture discs Fusible plugs Turbine overspeed trips Sentinel valves Safety relief valves - CORRECT ANSWER-d The oil used in ____ must be able to dissipate the compressor heat and be easily separated from the refrigerant. refrigeration compressors reciprocating pumps air compressors steam turbines gas turbines - CORRECT ANSWER-a The antifriction bearing housing should have 2/3rd of empty space remaining after being topped up with ____. crude water lubrication mineral oil grease - CORRECT ANSWER-e Internal ____ is not required for dynamic type compressors. seals lubrication pressure monitoring corrosion monitoring temperature monitoring - CORRECT ANSWER-bLow pressure or high pressure are the two primary classifications of ____. centrifugal pumps sump pumps boilers draft fans pressure controllers - CORRECT ANSWER-e The boiler feedwater becomes increasingly ____ as it approaches the measurement of zero. acidic neutral softer basic alkaline - CORRECT ANSWER-a The following hydrocarbon(s) may be entrained in a natural gas stream: Propane Butane Ethane Methane All of the above - CORRECT ANSWER-e Although ____ is created, high viscosity oils are still preferred for low speed/high load systems. lower floc point oils lower oil friction high pour point oils high velocity oils higher oil friction - CORRECT ANSWER-e Every shift the boiler water should be ____. filled with dissolved solids tested condensed replaced evaporated - CORRECT ANSWER-b Ammonia refrigerants have a high affinity for ____.non-condensable gases corrosion coagulants water flocculants - CORRECT ANSWER-d A ____ is a simple machine with two or more pulleys with a rope or cable threaded between them. hoist hacksaw block and tackle scaffolding portable grinder - CORRECT ANSWER-c ____ is one of the primary disadvantages of electric heating. Response time Increased corrosion Increased operating cost Decreased heat output Increased maintenance costs - CORRECT ANSWER-c ____ protocol should be used if the boiler will be exposed to subfreezing temperatures or will be shut down for an extended period or when there will be no foreseeable urgency to restart the boiler. Hot boiler lay-up Ready boiler lay-up Wet boiler lay-up Active boiler lay-up Dry boiler lay-up - CORRECT ANSWER-e A hammer is classified as a ____. recording device power tool hand tool measurement device calibration device - CORRECT ANSWER-c ____ is too toxic to be used as a refrigerant in building air conditioning systems. Water FreonLithium Bromide Air Ammonia - CORRECT ANSWER-e The biological breakdown of bacteria in a closed vessel could produce ____. water air precipitation oxygen methane gases - CORRECT ANSWER-e