BOMA HVAC EXAM | 367 QUESTIONS | WITH
ACUAL SOLUTIONS!!
What happens when room temperature soda is poured into a glass of ice ?
Answer - The ice melts because it is absorbing heat from the soda .
The compressor in a refrigeration system Answer - pumps the refrigerant
throughout the system
To control ice build - up on a heat pump outdoor coil in the heating cycle a
______ is used . Answer - pressure differential switch
The total pressure of a confined mixture of gases is the sum of the pressures of
each of the gases in the mixture . This is known as Answer - Dalton's Law
When moisture is present in a refrigeration system , it will react with the
refrigerant and the oil to form_ Answer - acid
A direct expansion - type evaporator is also called a Answer - dry-type
evaporator
Positive displacement compressors have crankcase heat to Answer - prevent
refrigerant migration to the compressor
If the power element of a TX valve loses its charge the Answer - refrigerant
flow to the coil will stop
,The pressure in a refrigeration system is changed in the Answer - compressor
and expansion device
Where is cooling produced Answer - In the evaporator
Where is heat content the highest Answer - Entering the compressor
Where is heat content decreased the most ? Answer - The condenser
Where is the compressor located Answer - Between the condenser and
evaporator
Where does the state of refrigerant change from liquid to a vapor Answer -
The evaporator
What part of the system is pressure the lowest Answer - The evaporator
(T/F) A Compressor raises the pressure and lowers the temperature of the
refrigerant Answer - False
Rotary is what type compressor Answer - Positive displacement
If a thermal expansion valve stays closed what would be the result Answer -
The valve would not be the load and the unit will heat up
What type of metering device is used in a centrifugal chiller Answer - A high
side float
,Which compressor require the least amount of maintenance Answer -
Centrifugal
What opens the TXV Answer - The power element of the assembly
T/F the purpose of a solenoid valve in a refrigeration system is to start and stop
the refrigerant flow Answer - True
What causes oil to foam Answer - Refrigerant in the oil
What determines the corrosion tendency of oil Answer - The sulfur content
What would cause a compressor to overload Answer - Starting under a warm
evaporator load
The evaporator im a refrigeration system Answer - Absorbs heat from the
product to be cooled
Moisture reacts with refrigerant and oil to form Answer - Acid
A direct expansion type evaporator is also called a Answer - Dry type
evaporator
The condenser Answer - rejects the heat from the refrigerant
Positive displacement compressors have crankcase heat to Answer - Prevent
the refrigerant migration to the compressor
, If the power element of a TX valve loses its charge, the___. Answer -
refrigerant flow to the coil will stop
Most of the heat energy in the suction vapor entering the compressor is
Answer - Latent heat
If the thermal bulb assembly develops a leak , what will occur Answer - The
bulb pressure will reduce and the valve will close
The approach of a cooling tower is the Answer - difference in temperature
between the entering air wet-bulb temperature and the sump water
temperature
At what locations in a refrigeration system does the saturation pressure
correspond to the saturation temperature Answer - Evaporator and condenser
A split phase motor can use what to energize and de-energize the start winding
? Answer - Potential relay, current relay, and a centrifugal switch
Temperature is an indicaron of the Answer - Amount of molecular activity in
the material
What can cause high suction pressures Answer - Defective compressor valves
What can cause an expansion valve to operate erratically Answer - Vapor in the
liquid line, bad compressor, low refrigerant charge.
What is a probable cause of a broken valve in the compressor Answer - Liquid
slugging
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