Metering Device Basics
This is the main job of a metering device in an HVAC system.
What is controlling refrigerant flow into the evaporator?
This fixed metering device is commonly used in refrigerators and cannot adjust flow.
What is a capillary tube?
This is defined as the temperature of vapor above its boiling point.
What is superheat?
This is used while brazing to prevent oxidation inside the system.
What is nitrogen?
This law regulates refrigerant handling and protects the environment.
What is EPA 608?
This happens to refrigerant pressure when it passes through a metering device.
What is pressure drops?
This device allows you to change sizes but still does not adjust to load conditions.
What is a fixed orifice (piston)?
This condition indicates not enough refrigerant in the evaporator.
What is high superheat?
This component removes moisture and contaminants from the system.
What is a filter drier?
This action must be done before opening a refrigeration system.
What is recovering refrigerant?
This is the location where a metering device is installed.
What is at the inlet of the evaporator coil?
This metering device uses a sensing bulb and adjusts based on superheat.
What is a TXV?
This dangerous condition can cause liquid refrigerant to return to the compressor.
What is low superheat (floodback)?
This is a common sign of a restriction in a filter drier.
What is a temperature drop across the drier?
This illegal act involves releasing refrigerant into the atmosphere.
What is venting refrigerant?
This process begins after refrigerant passes through the metering device and enters the evaporator.
What is boiling (phase change)?
This advanced device uses sensors and a control board to precisely regulate refrigerant.
What is an EEV?
Compressors are designed to compress this state of refrigerant only.
What is vapor?
This is often blamed for problems but is usually not the real issue.
What is a TXV?
These refrigerants have the highest ozone depletion potential.
What are CFCs?
This is the main reason metering devices are critical for cooling performance.
What is they help create the phase change needed to absorb heat?
This metering device can have 200+ steps between fully open and closed.
What is an electronic expansion valve (EEV)?
This part helps distribute refrigerant evenly through the evaporator coil.
What are distributor tubes?
These are two real causes often mistaken for metering device failure.
What are airflow problems and dirty systems?
This gas is used for leak testing, but oxygen must never be used because of this risk.
What is explosion risk?