Raypak 751 manual Combustion and Ventilation Air, Outdoor Installations, Indoor Units, Direct Vent

Fig. 2: Minimum Clearances from Combustible

Surfaces

Outdoor Installations

Raypak Advanced Design Boilers are design certified by CSA for outdoor installation. Roof water drainage must be diverted away from boilers installed under overhangs.

Heater Side	Min. Clearance from
	Combustible Surfaces
Rear	12” (water side)
Right	36”
Left	36”
Top	0”
Vent	1”

Table C: Clearances – Outdoor Installations

WARNING: Combustion air inlet (blower air inlet) should have 6" minimum clearance from any obstruction, i.e. walls or other appliances.

Combustion and Ventilation Air

Indoor Units

The boiler must be supplied with sufficient quantities of non-contaminated air to support proper combustion and equipment ventilation. Combustion air can be sup- plied via conventional venting, where combustion air is drawn from the area immediately surrounding the boil- er, or via direct vent, where combustion air is drawn directly from outside. All installations must comply with the requirements of NFGC for U.S., CSA B149 for Canada, and all local codes.

NOTE: In calculating free area, the required size of openings for combustion, ventilation, and dilution air shall be based on net free area of each opening. If the free area through a design of louver or grill is known, it shall be used in calculating the size opening required to provide the free area specified. For additional information, refer to the latest NFGC code requirements.

Direct Vent

If outside air is drawn through a vent pipe directly to the unit for combustion:

1.Install combustion air direct vent in accordance with the Venting section of this manual.

2.Provide for adequate ventilation of the space occupied by the boiler(s) by an opening(s) for ven- tilation air at the highest practical point communicating with the outdoors. The total cross sectional area shall be at least one (1) square inch of free area per 20,000 BTUH of total input rating of all equipment in the room when the opening is communicating directly with the outdoors or through vertical duct(s). The total cross sectional area shall be at least one (1) square inch of free area per 10,000 BTUH of total input rating of all equipment in the room when the opening is com- municating with the outdoors through horizontal duct(s).

3.In cold climates, and to mitigate potential freeze- up, Raypak highly recommends the installation of a motorized sealed damper to prevent the circula- tion of cold air through the boiler during the non-operating hours.

CAUTION: Remove the screen off the blower inlet and install a screen (1/2"-3/4" mesh) on the inlet elbow.

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