Desa C Owner's Operation And Installation Manual

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Desa C Owner's Operation And Installation Manual Manual pdf 5 page image

104415-01LFor more information, visit www.desatech.comFor more information, visit www.desatech.com5540,00033,00073,000Unusually tight construction is defined as constructionwhere:a. walls and ceilings exposed to the outside atmospherehave a continuous water vapor retarder with a ratingof one perm (6 x 10-11 kg per pa-sec-m2 ) or less withopenings gasketed or sealedandb. weather stripping has been added on openable win-dows and doorsandc. caulking or sealants are applied to areas such asjoints around window and door frames, between soleplates and floors, between wall-ceiling joints, betweenwall panels, at penetrations for plumbing, electrical,and gas lines, and at other openings.If your home meets all of the three criteria above,you must provide additional fresh air. SeeVentilationAir From Outdoors, page 6.If your home does not meet all of the three criteria above,proceed toDetermining Fresh-Air Flow For Heater Loca-tion, below.Confined and Unconfined SpaceThe National Fuel Gas Code, ANSI Z223.1/NFPA 54 defines aconfined space as a space whose volume is less than 50 cubic feetper 1,000 Btu per hour (4.8 m3 per kw) of the aggregate input ratingof all appliances installed in that space and an unconfined space asa space whose volume is not less than 50 cubic feet per 1,000 Btu perhour (4.8 m3 per kw) of the aggregate input rating of all appliancesinstalled in that space. Rooms communicating directly with thespace in which the appliances are installed*, through openings notfurnished with doors, are considered a part of the unconfined space.* Adjoining rooms are communicating only if there are doorlesspassageways or ventilation grills between them.DETERMINING FRESH-AIR FLOW FORHEATER LOCATIONDetermining if You Have a Confined orUnconfined SpaceUse this work sheet to determine if you have a confined or unconfined space.Space: Includes the room in which you will install heater plus any adjoiningrooms 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. (ceilingheight) = 2560 cu. ft. (volume of space)If additional ventilation to adjoining room is supplied with grills or open-ings, add the volume of these rooms to the total volume of the space.AIR FOR COMBUSTION ANDVENTILATIONContinuedWARNING: If the area in which the heater may beoperated is smaller than that defined as an uncon-fined space or if the building is of unusually tightconstruction, provide adequate combustion and ven-tilation air by one of the methods described in theNational Fuel Gas Code, ANSI Z223.1/NFPA 54 Sec-tion 5.3 or applicable local codes.2. Multiply the space volume by 20 to determine the maximum Btu/Hrthe space can support.__________ (volume of space) x 20 = (Maximum Btu/Hr the spacecan support)Example: 2560 cu. ft. (volume of space) x 20 = 51,200 (maximumBtu/Hr the space can support)3. Add the Btu/Hr of all fuel burning appliances in the space.Vent-free heater _____________ Btu/HrGas water heater* _____________ Btu/HrGas furnace _____________ Btu/HrVented gas heater _____________ Btu/HrGas fireplace logs _____________ Btu/HrOther gas appliances* + _____________ Btu/HrTotal = _____________ Btu/Hr* Do not include direct-vent gas appliances. Direct-vent draws com-bustion air from the outdoors and vents to the outdoors.Example:Gas water heater _____________ Btu/HrVent-free heater + _____________ Btu/HrTotal = _____________ Btu/Hr4. Compare the maximum Btu/Hr the space can support with the actualamount 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)73,000 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 mustprovide additional fresh air. Your options are as follows:A. Rework worksheet, adding the space of an adjoining room. If the ex-tra space provides an unconfined space, remove door to adjoiningroom or add ventilation grills between rooms. See Ventilation Air FromInside Building, page 6.B. Vent room directly to the outdoors. See Ventilation Air From Out-doors, 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.AIR FOR COMBUSTION AND VENTILATIONProviding Adequate Ventilation (Cont.)Determining Fresh-Air Flow for Heater Location