United CoolAir Glossary
Lacquer
Protective coating or finish that dries to form a film by evaporation of a volatile constituent.
Ladder diagram
Electrical diagram that indicates order of electrical devices in a specific electrical circuit.
Lag
Delay in response.
Lamp, steri
Lamp that has a high-intensity ultraviolet ray used to kill bacteria. Also used in food storage cabinets and in air ducts.
Latent heat
Heat energy absorbed in process of changing form of substance (melting, vaporization, fusion) without change in temperature or pressure.
Latent heat of condensation
Amount of heat released (lost) to change from a vapor (gas) to a liquid.
Latent heat of fusion
Amount of heat required to completely change one pound of a solid to a liquid at its melting point.
Latent heat of vaporization
Amount of heat required to change one pound of a liquid to a vapor (gas) at its boiling point.
Leak detector
Device or instrument, such as a halide torch, an electronic sniffer, or soap solution, used to detect refrigerant leaks.
Limit control
Control used to open or close electrical circuits as temperature or pressure limits are reached.
Liquefied gases
A gas below a certain temperature and above a certain pressure, that becomes liquid.
Liquid
Substance whose molecules move freely among themselves, but do not tend to separate like those of gases.
Liquid absorbent
Chemical in liquid form that has the property to "take on" or absorb other fluids.
Liquid desuperheater
Valve that permits small flow of refrigerant to enter low side of systems to cool suction gas.
Liquid floodback
A surge of liquid returning to the compressor.
Liquid indicator
Device located in liquid line that provides a glass window through which liquid flow may be watched.
Liquid line
Tube that carries liquid refrigerant from the condenser or liquid receiver to the refrigerant control mechanism.
Liquid nitrogen
Nitrogen in liquid form used as a low¬ temperature refrigerant in expendable or chemical refrigerating systems.
Liquid receiver
Cylinder (container) connected to condenser outlet for storage of liquid refrigerant in a system.
Liquid receiver service valve
Two- or three-way manual valve located at the outlet of the receiver and used for installation and service purposes. It is sometimes called the king valve.
Liquid transfer method
Method of liquid refrigerant recovery in which the air conditioning unit is pressur¬ized and refrigerant is removed by the created pressure difference.
Liquid-vapor valve refrigerant cylinder
Dual hand valve on refrigerant cylinders that is used to release either gas or liquid refrigerant from the cylinder.
Liter
Metric unit of volume, equal to 61.03 in3.
Lithium bromide
Chemical commonly used as the absorbent in absorption cooling system. Water would then be the refrigerant.
Load
The calculated rate of heat loss or gain, usually measured in BTUH.
Localized controller
Independent energy control device located near the system it is controlling.
Locked rotor amperage
Initial current when initially closing a circuit, two to four times as high as the running current.
Lockout relay
A device that shuts down a circuit whenever a safety control device is open.
Low side
The parts of a refrigeration system subject to the evaporator pressure.
Low-pressure safety cutout
Motor protection device that senses low-side pressure. Control is wired in series with the motor and will shut off during periods of excessively low suction pressure. Also called low-side pressure indicator.
Low-side float valve
Refrigerant control valve operated by level of liquid refrigerant in low-pressure side of system.
Low-side pressure
Pressure in cooling side of refrigerat¬ing cycle.
Low-side pressure control
Device used to keep low-side evaporating pressure from dropping below certain pressure.
Low-side pressure limiter
See Low-pressure safety cutout.
LP fuel
Liquefied petroleum used as a fuel gas.