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BOMA-HVAC EXAM AND STUDY GUIDE LATEST 2025
TEST BANK| COMPLETE 450 ACTUAL EXAM
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) ALREADY GRADED A+|| BRAND NEW!!
The least likely cause at high suction pressure would be _____. - ANSWER - Not enough system load
A psychometric chart is a graphic representation of _____? - ANSWER - Thermodynamic properties
Enthalpy refers to the _____? - ANSWER - Measure of energy content of a substance
Which of the following natural laws has the least bearing on the science of air conditioning? - ANSWER - Boyle's law, Charle's Law & Dalton's Law.
What is an excellent heat carrier because it _____? - ANSWER - Has high specific heat
The element that makes up the most percentage of air is _____? - ANSWER - Nitrogen
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pg. 2 The quantity of air moving through a fan system is expressed in _____?
- ANSWER - Cfm
The dry bulb temperature is _____? - ANSWER - The room temperature taken by an ordinary thermometer.
It is commonly held that a relative humidity of _____ percent is desirable? - ANSWER - 30 to 50 percent.
The heat absorbed after the refrigerant has vaporized becomes _____? - ANSWER - Superheated
The heat required to melt 1 pound of ice at 32 degrees to water at sea level is equal to _____? - ANSWER - 144 BTUs
The temperature of which boiling takes place in any liquid is called the _____? - ANSWER - Saturation temperature
The low side float is controlled by the _____? - ANSWER - Evaporation of refrigerant in the evaporator
When chemically cleaning a water system which has scale, which of the following chemicals should be used? - ANSWER - Inhibited acid
_____, _____, _____ & _____ is the refrigeration cycle? - ANSWER - Expansion; evaporation; compression & condensation 2 / 4
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pg. 3 The expansion or contraction of a gas without a change in temperature is known as _____? - ANSWER - Adiabatic
Refrigeration effect takes place in the _____? - ANSWER - Evaporator
The heat picked up by the evaporator is the heat _____. - ANSWER - Given up by the medium or product being cooled.
In a mechanical refrigeration system, the compressor is located between the _____ and _____? - ANSWER - Evaporator and condenser
For practical purposes the low side of a refrigeration system includes the _____? - ANSWER - Evaporator
What is the primary surface and the secondary surface in an evaporator coil? - ANSWER - Tubes are primary, fins are secondary
The 2 classification of compressors are called? - ANSWER - Positive displacement and kinetic displacement
A 230 volt PFC compressor tries to start at 184 volts and trips on overload protection, the starting torque of the motor is _____? - ANSWER - Decrease by lower voltage
What is the advantage of a flooded type evaporator? - ANSWER - Provides better heat transfer 3 / 4
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pg. 4 The use of a mechanical shaft seal is necessary in an _____? - ANSWER
- Open type compressor
The heat rejected by the condenser is the heat of _____? - ANSWER - Compression and the heat absorbed by the evaporator
In a centrifugal chiller, the purge unit is used to _____? - ANSWER - Remove non-condensibles from the condenser
A single way to distinguish a capacitor for a DC circuit from one AC circuit is to _____? - ANSWER - check for polarity markings on the circuit
The automatic expansion valve is controlled by _____? - ANSWER - Evaporator coil superheat
The automatic expansion valve controls _____? - ANSWER - The evaporator pressure
A liquid line heat exchanger _____. - ANSWER - Subcools liquid refrigerant
Which type of expansion valve is seldom used for refrigeration systems?
- ANSWER - Hand operated
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