2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Flammable Refrigerant
A flammable refrigerant is any working fluid used in HVAC…
Flare Connection
A mechanical refrigerant pipe joint made by forming the end…
Flare Fitting
A flare fitting is a mechanical connection that uses a…
Flaring
Flaring is a tube-joining technique that creates a 45-degree conical…
Flash Gas
Flash gas is vapor that forms when high-pressure liquid refrigerant…
Flash Injection
A technique used in cold-climate heat pump compressors where a…
Flash Point
Flash point is the lowest temperature at which a volatile…
Flash Point Refrigerant
Flash point for refrigerants is the lowest temperature at which…
Flash Tank Economizer
A type of vapor injection system that uses a flash…
Flat Plate Collector
A flat plate collector is the most common solar thermal…
Flat Rate Electric
Flat rate electric pricing charges a consistent per-kilowatt-hour (kWh) rate…
Flat Rate Pricing
Flat rate pricing is a service pricing method where HVAC…
Flex Duct
Flex duct is a flexible, insulated ductwork made from a…
Flexible Connection HVAC
A flexible connection is a ductwork or piping joint using…
Flexible Connector
A flexible connector is a short hose or corrugated metal…
Float Switch
A float switch is a safety device that detects water…
Float Valve
A float valve is a mechanical valve that uses a…
Floating Control
Floating control is a two-position or three-position control strategy where…
Floating Head Pressure Control
A control strategy that allows condensing pressure to drop as…
Flooded Evaporator
A shell-and-tube or shell-and-plate evaporator in which the refrigerant fills…
Flooding
Flooding occurs when liquid refrigerant enters the compressor cylinder instead…
Floor Furnace
A floor furnace is a self-contained, gas-fired heating appliance designed…
Floor Mounted Unit
A floor mounted unit is an HVAC terminal device designed…
Floor-Console Indoor Unit
A ductless indoor unit designed to mount at floor level…
Flooring Emissions
Flooring emissions are volatile organic compounds and formaldehyde released from…
Flow Diagram
A flow diagram illustrates the movement of fluids or gases…
Flow Hood Measurement
A flow hood is a portable testing device that measures…
Flow Hood Measurement Tool
A flow hood is a large fabric hood that captures…
Flow Meter
A flow meter is an instrument that measures the volume…
Flow Straightener
A device inserted in a duct consisting of parallel tubes,…
Flue Gas Analysis
Flue gas analysis measures the chemical composition of gases exiting…
Flue Gas Analyzer
A flue gas analyzer measures combustion byproducts in heating system…
Flue Gas Dew Point
The temperature at which water vapor in combustion exhaust gases…
Flue Gas Recirculation
A combustion control technique that routes a portion of exhaust…
Flue Inspection
A flue inspection examines the ductwork and passages that carry…
Fluid Cooler
A fluid cooler is an air-cooled heat exchanger that removes…
Fluorescent Dye Leak Detection
A method of leak location in which a UV-fluorescent dye…
Fluorescent Leak Dye
Fluorescent leak dye is a visible tracer chemical added to…
Flush Mount Solar
Flush mount solar describes panels installed parallel to roof surfaces…
Flushing
Flushing is the process of circulating a cleaning agent or…
Flux Residue Removal
The post-brazing process of cleaning flux from joints using hot…
Foaming Coil Cleaner
Foaming coil cleaner is a specialized chemical product that expands…
Food Service HVAC
Food service HVAC systems manage temperature, humidity, and air quality…
Forced Air Furnace
A forced air furnace is a heating system that uses…
Forced Draft
A combustion air arrangement in which a blower pushes air…
Forced Draft Cooling Tower
A forced draft cooling tower uses a fan mounted at…
Formaldehyde
Formaldehyde is a colorless, pungent gas released from building materials,…
Formaldehyde Sources
Formaldehyde Sources are building materials and furnishings that emit formaldehyde…