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Helpful Stove Terms

Air Shutter

An opening in the tube supplying gas to the burner. It draws primary air into the tube and mixes it with the gas before the gas goes to a main burner and is ignited.

Air Wash

As the primary air enters the firebox it is pre-heated and directed toward the glass on the front door. The constant "washing" of that hot air over the glass helps keep soot and creosote from building up on the glass. One of the other key elements of HearthStone’s clean glass technology is the use of "Infrared Reflective Ceramic" glass. Used in conjunction with the air wash, this glass helps keep the glass clean for maximum fire enjoyment.

Alcove

A recessed or built in area of a room usually including both sides and top.

B-Vent

Factory built, double-wall metal pipe for venting gas appliances with draft hoods and other appliances listed for use with Type B Gas Vent. It consists of an aluminum inner wall and a galvanized or galvalum outer wall with a dead air space between the walls.

Back drafting (back puffing)

A term to describe the condition when the flow of combustion products in a venting system reverses direction.

BTU (British Thermal Unit)

The amount of energy it takes to heat one pint of water one degree Fahrenheit.

Carbon Monoxide

A poisonous, combustible gas formed by incomplete combustion of carbon or reduction of carbon dioxide.

Cast Iron

A material used in many stoves. Iron is heated to a liquid form and poured into molds, usually with decorative detailing.

Catalytic Combustor

A coated ceramic "honeycomb" often used to reduce flue gas emissions.

Chimney Connector

The pipe that connects a fuel-burning appliance to a chimney.

Class "A" Chimney

A residential type chimney suitable for use at 1000ºF, which complies with the optional 10-minute 2100ºF test. Such chimneys are labeled as Type HT and are required for certain solid-fuel applications.

Close Clearance Stove Pipe

A double wall stove pipe usually consisting of an inner pipe, a small dead air space and an outer pipe. Used as a chimney connector it often reduces the necessary clearances to a combustible surface considerable over single wall stove pipe.

Coaxial Venting System

A Direct-Vent venting system using a larger outside diameter pipe for the fresh air intake and a smaller diameter pipe inside the outer pipe for exhaust gases. Usually the inside pipe is either 4" or 5" in diameter while the outside pipe is either 6⅝" or 8" in diameter.

Collinear Venting System

A Direct-Vent venting system using two separate pipes running next to each other. Normally one of the pipes is 3" or 4" in diameter

Combustible Material

Material made of, or surfaced with wood, compressed paper, plant fibers, plastics, or other material that can ignite and burn, whether flame proofed or not, whether plastered or unplastered.

Convection

The transmission of heat by air. Heated air rises and circulates.

Creosote

Chimney and stove pipe deposits originating as condensed wood smoke (including vapors, tar and soot). Creosote is often initially liquid, but may dry to pryrolze to a flaky or solid form.

De-pressurization

A condition when the air pressure in the home is less than the air pressure outside the home. It can be caused by inadequate ventilation or the use of other home appliances such as a furnace blower, or an exhaust fan in the kitchen or bathroom. It leads to back drafting or spillage in a conventional vent system. Depressurization is common in new, tightly constructed homes.

Direct-Vent

A venting system in which 100% of the combustion air is drawn from the outside and all the combustion products are returned to the outside.

Double Heat Exchanger:

What is a heat exchanger: A heat exchanger helps to quickly transfer heat from inside the firebox into the room, before the heat goes up the chimney. The better and more numerous the heat exchanger(s), the more efficient the stove.

What is a double heat exchanger? Most gas-fired heaters have a single heat exchanger. HearthStone gas stoves are unique in that they have double heat exchangers. The first is the standard convective air chamber surrounding the firebox. HearthStone’s second heat exchanger consists of the massive, finned, cast iron unit attached to this tag. The shorter set of fins extend downwards into the firebox, directly into the path of the flames. The longer fins face upwards, directly into the path of convection air heating your room.

What is the result? Our finned cast iron heat exchanger helps to quickly and efficiently transfer copious amounts of heat from the firebox into the living space. The result is high efficiency and maximum output for your heating dollar.

Draft

The pressure difference between the hot flue gases inside the venting system and the cool air surrounding the venting system.

EPA Phase II

In 1988 the federal government issued strict emission controls on woodstoves. These standards were instituted in two phases. All stoves built after July 1, 1992 must meet the stricter standards outlined in the second phase of that regulation.

Factory-Built Chimney

A chimney composed of listed factory-built components that is easy to assemble to form the completed chimney. They conform to safety and building codes. They are air cooled or insulated. Designed to remove combustion by-products.

Factory-Built Fireplace

A fireplace composed of listed, factory-built components assembled in accordance with the terms of the listing.

Glass

The window on the door(s) of your HearthStone gas or wood stove is not actually glass at all. It is a technologically advanced material, able to withstand temperatures of over 200º F and rapid temperature changes with no change in strength or durability.

Hearth Extension

A noncombustible surfacing applied to the floor area extending in front of and at the side of the hearth opening of a fireplace or a fireplace stove

Heat Life

The length of time a stove stays hot after burning a load of fuel.

Listed

Equipment, materials, or services included in a list published by an organization acceptable to the authority having jurisdiction. The listing states either that the equipment, material or service meets identified standards or has been tested and found suitable for a specific purpose.

Masonry Chimney

A field-constructed chimney of solid masonry units, including brick, stone, listed masonry material, usually lined with fire clay flue liners.

Millivolt (Mv)

Unit of electromotive force equal to one-thousandth of a volt.

Negative pressure

See depressurization

NFPA 211

National Fire Protection Agency standard #211 "Standard for Chimneys, Fireplaces, Vents and Solid Fuel-Burning Appliances 2000 Edition".

NFPA 54

National Fire Protection Agency standard #54 "National Fuel Gas Code" .

Non-catalytic

Non-catalytic stoves have a series of secondary air tubes under the baffle in the top of the firebox. These tubes draw a precise amount of heated air, inject it into the fire and actually cause any particles in the smoke to burn. Consequently your stove is helping to keep our environment clean while you enjoy the benefit of more heat out of less wood.

Noncombustible Material

A material that, in the form in which it is used and under the conditions anticipated, does not ignite, burn, support combustion or release flammable vapors, when subjected to fire or heat.

Oxygen Depletion Sensing (ODS) Pilot Assembly

A pilot burner found in Vent-Free appliances, which can sense and respond to the change in oxygen level. It consists of an orifice for gas flow and a bimetallic air shutter, a thermocouple and a spark electrode. Before the oxygen level reaches 18% the flame lifts off and causes the thermocouple to cool shutting off the gas flow to the burners.

Piezo Electric Igniter

A device which delivers an igniting spark by mean of pressure on a crystal.

Radiation

The transmission of heat via radiant energy.

Regulator

A device for controlling and maintaining a uniform outlet of gas pressure. Usually part of a combination gas valve.

Sealed Combustion System

A Direct-Vent system. A self-contained combustion system in which all the combustion air is drawn from the outside and all the combustion product is returned to the outside. The combustion system does not interact with the home.

Sediment Trap (Drip leg)

A required part of every gas installation, which allows a collection point for moisture, and foreign particles (i.e. copper sulfide) that may be in the gas.

Soapstone

A metamorphic rock formed millions of years ago under intense heat and pressure. It evolved from a molten state deep within the earth with an unusually stable composition. Unlike other stones, it can withstand fire and dramatic changes in temperature. Other stones, such as granite and marble, also hold and radiate heat, but only soapstone is able to withstand direct flames indefinitely.

Spill Switch

A heat activated safety sensor, which detects flue gas flow reversal, which will shut an appliance off.

Thermocouple

A device consisting of two pieces of dissimilar metals joined together at one end (hot junction). When the hot junction is heated, the thermocouple produces DC Millivolts between 25-30 millivolts. Used to power the gas safety valve.

Thermopile

A number of thermocouples connected in series to produce more DC Millivolts than a single thermocouple. Depending on size the DC Millivolts range between 250 and 750 millivolts.

Thimble

Special metal or clay sleeves for wall and ceiling penetrations when installing a venting system to ensure that the proper clearance away from combustibles is maintained.

Vent-Free

Gas appliance systems where all combustion byproducts (mostly water vapor and carbon dioxide) are released into the same room environment as the appliance.

Water Column (W.C.)

Unit of measurement for gas pressure in inches of water. Approximately 28 inches water column equals one psi.

Zero-clearance fireplace

See Factory-built Fireplace.