Legislation & Refrigerant
This 1987 international environmental treaty was signed to protect the Earth's ozone layer by phasing out Chlorofluorocarbons (CFCs) like R-12.
What is the Montreal Protocol?
Mounted in front of the radiator, this component receives superheated high-pressure gas from the compressor and condenses it into a high-pressure liquid.
What is the condenser?
In fixed orifice tube systems, the size of the internal orifice diameter can be identified by this physical design feature.
What is the color of the orifice tube?
On an 80°F–90°F day, a properly functioning A/C system should output air within this temperature range.
What is 35°F to 45°F?
Accessible behind the glove compartment, this component removes dust and pollen from incoming air and often uses activated charcoal to neutralize cabin odors.
What is the cabin air filter (or particulate/pollen filter)?
Under Section 609 of the Clean Air Act, this is the maximum statutory fine per day for each separate violation of EPA rules regarding refrigerant handling
What is $37,500?
Located inside the dash, this component absorbs heat from passing cabin air, causing the low-pressure cold liquid refrigerant inside to boil into a gas.
What is the evaporator core?
Found in Thermal Expansion Valve (TXV) systems, this high-pressure side component filters debris, removes moisture, and separates gas bubbles to ensure 100% liquid reaches the expansion valve.
What is the receiver-drier?
Under normal system operation at 80°F–90°F ambient temperature, these are the expected pressure ranges for the low and high sides.
What are 35 to 45 PSI (low side) and 175 to 250 PSI (high side)?
On pneumatic vacuum-controlled HVAC systems, a loss of engine vacuum defaults air routing to this location as a safety feature.
What is defrost (windshield registers)?
This non-conductive synthetic lubricant is specifically formulated for high-voltage electrically-driven A/C compressors in hybrid and electric vehicles.
What is Polyol Ester (POE) oil?
This fixed displacement compressor design relies on an electromagnetic clutch cycling on and off to prevent evaporator freeze-up.
What is a cycling clutch piston compressor?
This component improves system efficiency by 10–15% by sub-cooling liquid refrigerant before the expansion valve while superheating returning cold vapor used on 1234yf systems.
What is an Internal Heat Exchanger (IHX)?
Rapid cycling of the compressor clutch where both low-side and high-side pressure gauge readings are lower than normal indicates this system condition.
What is a low refrigerant charge (undercharged system)?
This specific door inside the HVAC plenum dictates air temperature by routing air either through or around the heater core.
What is the blend door or air-mix door?
The EPA pays cash rewards up to this amount to citizens who report the illegal venting of chemical refrigerants.
What is $10,000?
Located on the low-pressure side of an orifice tube system, this component prevents liquid slugging by storing unevaporated liquid refrigerant and capturing moisture with a desiccant bag.
What is the accumulator?
In an accumulator, a small calibrated opening at the bottom of the internal U-shaped tube performs this critical function to protect the compressor.
What is drawing a metered amount of refrigerant lubricant (oil) back to the compressor?
If the low-side gauge drops into a deep vacuum while high-side pressure spikes extremely high (400–700+ PSI), the system is experiencing this fault.
What is a clogged metering device (or orifice tube/expansion valve restriction)?
If a blower motor works only on high speed but fails on lower speeds, this is the most likely defective component.
What is the blower motor resistor pack?
This 2016 expansion to the Montreal Protocol sets binding targets to phase down high-GWP hydrofluorocarbons (HFCs) like R-134a.
What is the Kigali Amendment?
This compressor alters its pressure output by moving a wobble or swash plate.
What is a variable displacement compressor?
This type of compressor uses orbiting spiral geometry to compress gas toward the center discharge port and is commonly driven by electric motors in hybrid/EV applications.
What is a scroll compressor?
During a static balance equalization test on a healthy system, high-side and low-side pressures should balance quickly within this duration after shutting down the A/C.
What is 15 to 30 seconds?
This type of electric HVAC actuator uses two wires for motor power and ground, and three wires connected to an internal potentiometer to signal the motor's exact position.
What is a 5-wire actuator?