DM-216 Heating and A/C System
behavior of heat
Best describes the branch of physics known as thermodynamics
three
How many state of matter are identifiable under normal atmospheric conditions
R-22
Most common refrigerant used in current reefer trailers
Both A and B
Tech A says all matter on earth contains some heat energy. Tech B says that a substance with no heat energy would have a temperature of minus 459 Fahrenheit or absolute zero.
Both A and B
Tech A says that all matter on earth contains some heat energy. Tech B says that a substance with no heat energy would have a temperature of minus 459 Fahrenheit or absolute zero.
Evaporator
The air conditioning component located in the cab
Btu
The amount of heat energy required to raise 1lb of water by 1 degree Fahrenheit is known as
light blue
The color of R-134a refrigerant container
R-134a
The common refrigerant used in current trucks
Conditions underhood ram air
The following is NOT a function of a truck air-conditioning system
conditions underhood ram air
This is NOT a function of a truck air conditioning system
Recover all refrigerant from the A/C station
What must be done with an A/C system before replacing any system components
When a substance is frozen to a solid state, heat energy is released.
When ice melts heat energy is absorbed
condenser
a component that is a heat exchanger
whenever a compressor needs to be isolated
a stem type valve should be front seated
tech A only
tech A wears safety goggles and rubber gloves when discharging the a/c system. tech b wears safety goggles and leather gloves when charging and leak testing the system
evaporator
the air conditioning component that is located in the cab
ram air effect
the airflow created by vehicle movement
1 btu
the amount of heat required to raise the temperature of 1lb of water by 1 degree F
evaporator
the coldest point in a properly function A/C circuit
the condenser
the component in an air conditioning system that is responsible fro removing heat from the circulating refrigerant
TXV
the component that regulates refrigerant flow to the evaporator
binary switch and trinary switch
the components that protect an A/C circuit from under pressure or over pressure
expansion valve
the dividing point from high/low pressure
cleaning the outer surface of the condenser with modulated compressed air and soap, repairing leaks in the evaporator coil and improving the performance of the engine cooling system
the following procedures may improve HVAC system performance
Joules
the metric measurement of heat enery
condensation stage
the stage in which typical refrigeration cycle changes from a high-pressure gas to a high pressure liquid
evaporation stage
the stage in which typical refrigeration cycle changes from a low pressure liquid to a low pressure gas
BTU
the standard measurement of heat energy to rate A/C specifications
high pressure line and low pressure line
the two main refrigerant lines are known as
a liquid changes to a gas and back to a liquid
what is a function of a refrigeration system
latent heat of vaporation
when a substance changes from a liquid to a gas, heat is absorbed. This is how the evaporator removes heat from the cab.
both A and B
when checking an A/C sight glass for moisture content of the refrigerant. Tech A performs the check with the air conditioner running immediately after starting the engine. Tech b says that some observable bubbles in the sight glass at system startup are
85 degrees Fahrenheit
A container of R-134a has a pressure of 95psig. What is the temperature?
Compressor stage
change a low pressure gas to a high pressure gas
condenser stage
changes from a high pressure gas to a high pressure liquid
expansion valve stage
changes from a high pressure liquid to a low pressure liquid
evaporator stage
changes from a low pressure liquid to a low pressure gas
latent heat of vaporization
heat energy required to change a liquid to a vapor without raising its temperature
condenser
heat exchanger, effected by the ram air effect
evaporator
located in the cab, removes heat from the cab
recharging cylinder
piece of equipment used to meter out a desired amount of specific refrigerant by weight
R-134a
refrigerant commonly used in current trucks