Raypak 503A Installation & Operating Instructions Manual

Raypak 503A Installation & Operating Instructions Manual Manual pdf 11 page image

11Air FilterAn air filter is supplied standard with the heater. Thisfilter is shipped loose for field installation. Refer to theAir Filter Kit Installation Instructions (Part No. 241338)for details.Direct VentIf outside air is drawn through the intake pipe directlyto the unit for combustion:1. Install combustion air direct vent in accordancewith Fig. 33 (horizontal) or Fig. 34 (vertical) of thismanual (pages 31 and 32, respectively).2. Ventilation of the space occupied by the heater(s)is recommended and can be provided by an open-ing(s) for ventilation air at the highest practicalpoint communicating with the outdoors. The totalcross-sectional areas should be at least 1 in.² offree area per 20,000 BTUH (111 mm² per kW) oftotal input rating of all equipment in the room,when the opening is communicating directly withthe outdoors or through vertical duct(s). The totalcross-sectional area should be at least 1in.² of freearea per 10,000 BTUH (222 mm² per kW) of totalinput rating of all equipment in the room, when theopening is communicating with the outdoorsthrough horizontal duct(s). Damage to the equip-ment due to inadequate ventilation of the space isnot a warrantable failure.3. In cold climates, and to mitigate potential freeze-up, Raypak highly recommends the installation ofa motorized sealed damper to prevent the circula-tion of cold air through the heater during thenon-operating hours.Motorized Combustion Air Dampers orLouversWhen dampers or louvers are communicating directlywith outside combustion air, they must be interlockedwith each appliance in the equipment room, to ensureproper operation. See field wiring connection sectionof this manual for proper wiring instructions, usingFan/Damper dry contacts and external interlock.TruSeal™ Combustion AirIn addition to the 3 previous steps, combustion air maybe ducted directly to the heater by using PVC, CPVCor sealed single-wall galvanized ducting. The duct willattach directly to the air collar located on the inline AirFilter Box (shipped loose), using 3-4 sheet metalscrews (not supplied) equally positioned around thecircumference of the duct. The screen assemblyshould be removed before attaching any air duct. Thescrews and duct connection point must be sealed withRTV (not supplied). TruSeal is generally used whendamaging contaminants are present in the mechanicalroom.All ducting MUST be self-supported.Conventional Combustion AirSupplyU.S. InstallationsAll Air from Inside the BuildingThe confined space shall be provided with TWO per-manent openings communicating directly with anadditional room(s) of sufficient volume so that the com-bined volume of all spaces meets the criteria for aroom large in comparison (NFGC). The total input of allgas utilization equipment installed in the combinedspace shall be considered in making this determina-tion. Each opening shall have a minimum free area of1 in.2 per 1,000 BTUH (2,225 mm 2 per kW) of the totalinput rating of all gas utilization equipment in the con-fined space, but not less than 100 in.2 (645 cm 2 ). Oneopening shall commence within 12 in. (305 mm) of thetop, and one opening shall commence within 12 in.(305 mm) of the bottom of the enclosure. The mini-mum dimension of air openings shall be not less than3 in. (76 mm) in any direction.CAUTION: Use TruSeal combustion air ifdamaging airborne contaminants are or may bepresent in the heater area. See the Appendix of thismanual regarding air contamination.Fig. 8: Air Filter Box