Desa FAS-3B Fresh AIR for Combustion Ventilation, Determining FRESH-AIR Flow for Heater Location

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OWNER’S MANUAL

FRESH AIR FOR

COMBUSTION AND

VENTILATION

Continued

DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION

Determining if You Have a Confined or Unconfined Space

Use this worksheet to determine if you have a confined or unconfined space.

Space: Includes the room in which you will install heater plus any adjoining rooms with doorless passageways or ventilation grills between the rooms.

1.Determine the volume of the space (length x width x height).

Length x Width x Height = ____________________ cu. ft. (volume of space)

Example: Space size 20 ft. (length) x 16 ft. (width) x 8 ft. (ceiling height) = 2560 cu. ft. (volume of space)

If additional ventilation to adjoining room is supplied with grills or openings, add the volume of these rooms to the total volume of the space.

2.Divide the space volume by 50 cubic feet to determine the maximum Btu/Hr the space can support.

_________________ (volume of space) ÷ 50 cu. ft. = (Maximum Btu/Hr the space can support)

Example: 2560 cu. ft. (volume of space) ÷ 50 cu. ft. = 51.2 or 51,200 (maximum Btu/Hr the space can support)

3.Add the Btu/Hr of all fuel burning appliances in the space.

Vent-free heater

___________________ Btu/Hr

 

 

 

 

 

Gas water heater*

___________________ Btu/Hr

Example:

 

 

 

Gas furnace

___________________ Btu/Hr

 

 

 

Gas water heater

 

40,000

Btu/Hr

Vented gas heater

___________________ Btu/Hr

 

Vent-free heater

 

+

18,000

Btu/Hr

Gas fireplace logs

___________________ Btu/Hr

Total

=

58,000

Btu/Hr

Other gas appliances* + __________________ Btu/Hr

 

 

 

 

 

Total

= __________________ Btu/Hr

 

 

 

 

 

*Do not include direct-vent gas appliances. Direct-vent draws combustion air from the outdoors and vents to the outdoors.

4.Compare the maximum Btu/Hr the space can support with the actual amount of Btu/Hr used.

____________ Btu/Hr (maximum the space can support)

____________ Btu/Hr (actual amount of Btu/Hr used)

Example: 51,200 Btu/Hr (maximum the space can support) 58,000 Btu/Hr (actual amount of Btu/Hr used)

The space in the above example is a confined space because the actual Btu/Hr used is more than the maximum Btu/Hr the space can support. You must provide additional fresh air. Your options are as follows:

A.Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adjoin- ing room or add ventilation grills between rooms. See Ventilation Air From Inside Building, page 6.

B.Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 6.

C.Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined.

If the actual Btu/Hr used is less than the maximum Btu/Hr the space can support, the space is an unconfined space. You will need no additional fresh air ventilation.

WARNING: If the area in which the heater may be operated is smaller than that defined as an unconfined space or if the building is of unusually tight construction, provide adequate combustion and ventilation air by one of the methods described in the National Fuel Gas Code, ANS Z223.1, 1992, Section 5.3 or applicable local codes.

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Contents What to do if YOU Smell GAS Infrared VENT-FREE Natural GAS HeaterInfrared Natural GAS Heater Safety InformationProduct Identification Product FeaturesLocal Codes UnpackingProducing Adequate Ventilation Fresh AIR for Combustion and VentilationUnusually Tight Construction Confined and Unconfined SpaceDetermining if You Have a Confined or Unconfined Space Fresh AIR for Combustion VentilationDetermining FRESH-AIR Flow for Heater Location Ventilation Air From Outdoors Ventilation AIRVentilation Air From Inside Building Installation Items InstallationLocating Heater Check GAS TypeMounting Bracket Installing Heater to WallRemoving Front Panel Of Heater Models FA-3B and FA-5B Methods For Attaching Mounting Bracket To WallPlacing Heater On Mounting Bracket Installing Bottom Mounting ScrewsAttaching Mounting Bracket To Wall Typical Inlet Pipe Diameters Connecting to GAS SupplyPressure Testing Gas Supply Piping System For Your Safety Read Before LightingPressure Testing Heater Gas Connections Operating HeaterLighting Instructions Manual Lighting ProcedureTo Select Heating Level To Turn OFF GAS to ApplianceThermostat Models FAS-3B and FAS-5B Inspecting Burner Cleaning and MaintenanceObserved Problem Possible Cause Remedy TroubleshootingInfrared Natural GAS Heater Top Service Hints SpecificationsService Publications Technical Replacement PartsParts Centrals AccessoriesManual Shutoff Valve GA5010 FAN Kits UH1000FB and UHS1000FBFA-3B Burner Assembly ODS/Pilot AssemblyIllustrated Parts Breakdown KEY FA-3B Description Parts ListFA-5B KEY FA-5B Description FAS-3B ODS/Pilot Assembly Burner AssemblyKEY FAS-3B Description QTY FAS-5B KEY FAS-5B Description QTY International Warranty Information