Glossary

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80/20 Rule - If the distance between parallel walls exceeds 100', the infra-red heater capacity along the perimeter should be at least 80% of the total system capacity with the remaining maximum 20% of the total system capacity located in parallel rows toward the center of the building.

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AGA - American Gas Association was a certification agency that tested our appliances to the standards for use in the USA. The testing portion of AGA is now Canadian Standards Association (CSA).

Air Intake Collar - Accessory for low intensity infrared heaters which allows connection of outside combustion air pipe to burner box.

Air Metering Damper - Balances a multiple vacuum infrared burner system by controlling the amount of air flowing through the tube run from either 2, 3, or 4 burners of the tube system.

Air Temperature Rise (ATR) - Air Temperature Rise can be found by taking the temperature of the discharge air minus the temperature of ambient air. The air temperature rise that a heater will produce can be found with the following formula: Air Temp rise = (BTU / Hr (out))/ 1.08 x Cfm

Airflow (Cfm) - Cubic Feet/Minute. The Cfm needed from a heater can be found with the following formula: Cfm = (Btu / Hr (out))/ Air Temp Rise x 1.08

ANSI - The acronym ANSI stands for American Nation Standards Institute.

ANSI Z223.1 - ANSI Z223.1 and CAN/CGA B149 are installation standards.

ANSI Z83.8 - ANSI Z83.8 and CGA2.8 are the gas-fired unit heater and gas-fired duct furnace standards.

Area of Coverage - The area heated by an infrared heater is measured at floor level. The mounting angle of infrared heaters affects the coverage area with the following relationship:

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Blocked Vent Safety Switch (BVSS) - Blocked vent safety switch or spill switch is a safety device to prevent spillage of flue products from gravity vented units. This was implemented in April of 1991.

British Thermal Unit (Btu) - The amount of heat required to raise 1 pound of water 1 degree Fahrenheit.

Btu/hr Output = Air temp rise x cfm x 1.08

Burner Box - The part of the low intensity infrared system that houses the burner and controls. CFM - Cubic feet per minute.

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Ceramic Tile - Modine high intensity infrared heaters utilize diamond face ceramic tiles for the heat exchanger. The diamond face has a greater surface area than flat ceramics, providing maximum heat transfer

CGA - Canadian Gas Association was a certification agency that tested our appliances to the standards for use in Canada. The testing portion of CGA is now Canadian Standards Association (CSA).

Chemicals (Contaminated/Corrosive Environments) - Corrosion causing substances (chlorides/fluorides). Some common substances would be Carbon Tetrachloride, Methyl Chloroform, Methylene Chloride, Perchloroethylene, Trichloroethylene, and Refrigerant 11, 12, 21, 114. Typical sources may include but would not be limited to: aerosol cans, dyes, degreasing compounds, road salt, swimming pools, plastic manufacturing, and scotch guard for fabric. Greenhouse fungicides and insecticides may include but not limited to: Ambush, Bravo, Chipco, Dacon, Dowco 179, Dramm VK-1, Dursban (2) RE, Ectiban, Ent 2711, Exotherm Termil, Forturf, Lorsban, Mavrik, Pentac Aquaflow, Pounce, Pyrinex, Rovral, Talstar, and Termil.

Class B Vent Material - Double wall vent.

Clearance to Combustible Materials - The certified minimum distance from combustible materials is based on the combustible material surface not exceeding 160°F at the specified distance in the unit manual.

CO (carbon monoxide) - Product of incomplete combustion. There is typically less that 50PPM vented to the atmosphere from a properly adjusted unit.

CO2 (carbon dioxide) - Product of complete combustion. The typical amount is 80,000 - 100,000 PPM vented to the atmosphere.

Coal Gas = Typically puts out 400 - 500 Btu/Cu Ft. Specific gravity is 0.5 - 0.6. Contact factory before operating on fuel types/ values other than listed in Installation and Service manual.

Combination Gas Control - Regulates the flow of gas to pilot & burner. ANSI requires electro./mech. redundant gas controls so in the event one operator (i.e. valve) fails to close, the other one will. This reduces the chance of unit overheating & causing a fire. There are two types of redundant valves, with & w/o Energy Cut-Off (ECO).

Combustion Air - Air that mixes with the unit fuel for proper combustion.

Combustion Air (Primary) - Air used for combustion with the gas for the unit. This air enters through the mixing tube with the gas.

Combustion Air (Secondary) - Air used to support the combustion process. This air travels from bottom of unit and comes up along burner.

Combustion Air Blower - Utilized to push or pull the products of combustion through the unit and vent.

Common Venting - The venting of two appliances into one vent pipe. Refer to applicable unit installation & service manual or the National Fuel Gas Code for a full description of requirements.

Conduction - The transmission of heat through solid objects by the exchange of energy from warmer molecules to cooler molecules.

Convection - The transmission of heat through gasses or liquids by the movement of masses of the gasses or liquids.

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Differential Pressure Switch - Senses vent pressure or differential system pressure to shut unit down in hazardous situations such as a blocked vent.

Direct Spark Ignition - Control system that sparks an electrodes to directly ignite the fuel.

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Energy Cut Off Device (ECO) - Provide redundancy for standing pilot while redundancy is built into the IPI valves.

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Fan Delay Relay - Allows the heat exchanger to warm up before fan starts as well as cool down before fan turns off.

Flame Sensing Rod (Flame Sensor) - Senses flame to prove proper ignition.

Flue Gas - A mixture of air and products of combustion.

Flue Gas Temperatures - The temperature of the air and exhausted combustion products. Low intensity infrared heater flue gas temperature cannot exceed 400°F above room temperature. Typically, a gravity-vented unit will have flue temperatures in the area of 400°F and power vented will have temperatures in the area of 380°F.

Flue Gas Volume - The flue gas volume for gas-fired unit heaters can be roughly approximated by 0.4 x Mbh for gravity vented units and 0.3 x Mbh for power exhausted units.

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Gas Orifice - Regulates amount of fuel input into unit. The gas orifice can be found screwed into gas manifold.

Gravity Vented - Natural draft of the combustion process.

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Hazardous Locations - Any location that may be classifed by the NEC or local codes. Modine gas-fired heaters are not designed for use in hazardous areas. Refer to Modine Technical Times TT-3-90.

Heat Loss - Amount of energy that escapes from the space that is being heated.

Heat Stratification - This is the natural process of warm air rising and cool air sinking. This results in a temperature gradient from the floor to ceiling. This is termed "heat stratification".

Heat Throw - The distance heater horizontally thrusts air into the space. Currently there is not a universal standard for measuring this distance which results in different manufacturers using different methods of measurement.

High Altitude - Gas-fired unit heaters require an orifice size change from standard after 2000'. For USA, output is derated 4% for each 1000 feet above sea level. For Canada, the output is derated 10% for elevation 2000' to 4500' and an additional 4% for each 1000 there after.

Hot Surface Ignition - Silicon carbide hot surface igniter (HSI) is energized and ignites gas at the burner.

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IAS - International Approval Services used to carry the AGA logo. The agency has since been re-named as the Canadian Standards Association (CSA).

Intermittent Pilot Ignition (IPI) - Allows the pilot to remain off in non call for heat situations. Upon a call for heat, the pilot is lit which in tern is used to light the main burner.

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Limit Control - The high limit switch shuts off gas controls in the event that the discharge temperature of unit exceeds its allowed amount.

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Millivolt Control System - Control system for high intensity infrared heater. Utilizes manually-lit standing pilot ignition. Self-energizing control system. 750 mV powerpile (type of thermocouple) energized from heat of pilot flame and closes control circuit.

Mounting Angle - The mounting angle is the angle from the horizontal plane at which the infrared heater is installed. Low intensity infrared is approved for a 00 to 45° mounting angle. High intensity infrared units must be mounted between 100 and 35°.

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Natural Gas - The most common gas used for unit heaters. Standard is 1048 Btu/Cu Ft but can range from 925 - 1125 Btu/Cu Ft. Specific gravity is .5 - .7. Contact factory before operating on fuel types/ values other than listed in Installation and Service manual.

NOX - Made up of NO (nitrogen oxide) and NO (nitrogen dioxide). NOX are the nitrogen oxides that are combustion by products that contribute to ozone formation. Typically, you will find less that 110 PPM vented to the atmosphere. Currently gas unit heaters are not required to undergo testing for NOX.

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Outlet Velocity - The speed at which air is discharged from the unit. Modine publishes in Feet/Minute.

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Partial Building Heating - Heaters are used to heat a section of a building such as an assembly line or office within a warehouse or factory.

Power Exhauster - Utilized to push or pull the products of combustion through the unit and vent.

Pre-Purge/Post Purge - Clears the vent/heat exchanger before and after unit fires by turning on the power exhauster.

Propane Air Mixtures - A mixture of air and propane intended to approximate the properties of natural gas. This can be used in a natural gas shortage. It typically puts out 1425 - Btu/Cu Ft with a specific gravity of 1.29. Contact factory before operating on fuel types/ values other than listed in Installation and Service manual.

Propane Gas - Common gas used for unit heaters. Propane is a hydrocarbon (C3H8) and is also referred to as liquefied petroleum gas, LP-gas, and LPG. Propane gas is typically 2500 - Btu/Cu Ft. Has specific gravity of 1.53. Contact factory before operating on fuel types/ values other than listed in Installation and Service manual. Also, one gallon of propane gas contains 91,500 Btu's.

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Radiant Efficiency - No requirements for radiant efficiency currently exist within infrared standards.

Radiation - The transmission of energy through space by infrared energy rays emitted from a hot surface. The energy heats only the objects it strikes.

Recommended Mounting Height - The height determined through testing which will result in the maximum comfort for the occupants.

Reflector - Bright aluminum bent panels to reflect the radiant heat that is directed up back to the floor and sides.

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Safety Pressure Switch - Senses positive vent pressure or differential system pressure to shut unit down in hazardous situations such as a blocked vent.

Seasonal Efficiency - Takes into account the energy in from gas and energy delivered to space while running but also the losses out flue and inefficiencies on start-up and shut-down. While there currently is not a standard for testing seasonal efficiency for gas-fired unit heaters it has been estimated and is shown in 10-115 as well as the fuel savings calculations.

Secondary Heat Exchanger - The recuperative tube used in the current separated combustion unit. This allows for a higher thermal efficiency unit.

Separated Combustion - Uses air exterior of space for combustion.

Sewage Gas = Typically puts out 420 - 650 Btu/Cu Ft. The specific gravity is .55 - .85. Contact factory before operating on fuel types/ values other than listed in Installation and Service manual.

Specific Gravity - Weight of gas compared to weight of air at 1.0.

Spot Heating - The direction of heat to particular areas while not providing total building heating.

Stacking Height - Defines maximum height at which combustible material can be stacked under an infrared heater. Formula: Stacking Height = Mounting Height - Minimum Clearance to Combustibles

Stainless Steel in Heat Exchanger Design - Refer to Modine Technical Times TT-1-90. Stainless steel types 321, 430, and 409 are discussed in detail.

Standing Pilot - Pilot is lit during call and no call for heat from the space. On gas controls w/o ECO, a 2nd operator (valve) will also close when thermostat is satisfied (which is loss of power). On a loss of gas, a 3rd operator will actually close. On redundant gas controls w/ ECO, a 2nd valve will close only when gas is interrupted or temperature of ECO exceeds set point.

Standing Pilot vs. IPI - Standing pilot burns 1000 Btu/Hr with 100,000 Btu's = 1 Therm. If the cost is $1.50 for (1) Therm, you can burn a pilot 100 hours for $1.50. Intermittent Pilot Ignition systems are popular due to economy. Two types are Hot Surface Ignition (HSI) and Spark Ignition.

Static Pressure - The amount of pressure at unit created from friction of air within the duct work.

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Therm - A therm is a unit of energy measurement used for natural gas. One therm is equivalent to 100,000 Btu's.

Thermal Efficiency - Efficiency of a unit while running at steady state. Only takes into account the energy in from gas and energy delivered to space while running. Note that efficiency designations differ between units manufactured in North America and other countries. For example, efficiency ratings for equipment certified in Europe would be significantly lower using North American efficiency standards.

Titanium Aluminized Steel Tubes - Alloy heat exchanger tubes utilized as the first section of low intensity infrared systems of 150,000 Btu/hr and up where tube temperatures are higher.

Total Building Heating - When the heating system is to counteract total building heat loss.

Tube - Heat exchanger for low intensity infrared heaters.

Turbulator Baffle - Located in the last tube of low intensity infrared heaters. Agitates flue gasses to increase heat transfer at the end of the tube system.