D.Install Vent Connector from draft hood or vent damper to chimney. See Figure 30.
1.Do not connect into same leg of chimney serving an open fireplace.
2.Vent pipe to chimney must not be smaller than outlet on draft hood or vent damper. Type B is recommended, but
3.Where two or more appliances vent into a common vent, the area of the common vent should be at least equal to the area of the largest vent plus 50% of the area in the additional vent(s). Do not connect the vent of this appliance into any portion of mechanical draft systems operating under positive pressure.
4.Horizontal run should be as short as possible. The maximum length of an uninsulated horizontal run must not exceed 75% of the height of the chimney.
5.Vent pipe should have the greatest possible initial rise above draft hood consistent with headroom available and required clearance from adjacent combustible building structure. Vent pipe should be installed above bottom of chimney to prevent blockage.
6.Vent pipe should slope upward from draft hood to chimney not less than one inch in four feet. No portion of vent pipe should run downward or have dips or sags. Vent pipe must be securely supported.
7.Vent pipe must be inserted into but not beyond inside wall of chimney liner. Seal tight between vent pipe and chimney.
E.If an Existing Boiler is Removed:
When an existing boiler is removed from a common venting system, the common venting system is likely to be too large for proper venting of the appliances remaining connected to it.
At the time of removal of an existing boiler, the following steps shall be followed with each appliance remaining connected to the common venting system placed in operation, while the other appliances remaining connected to the common venting system are not in operation:
1.Seal any unused openings in the common venting system.
2.Visually inspect the venting system for proper size and horizontal pitch and determine there is no blockage or restriction, leakage, corrosion, and other deficiencies which could cause an unsafe condition.
3.Insofar as is practical, close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building. Turn on clothes dryers and any appliance not connected to the common venting system. Turn on any exhaust fans, such as
4.Place in operation the appliance being inspected. Follow the Lighting (or Operating) Instructions. Adjust thermostat so appliance will operate continuously.
5.Test for spillage at the draft hood relief opening after 5 minutes of main burner operation. Use the flame of a match or candle, or smoke from a cigarette, cigar or pipe.
6.After it has been determined that each appliance remaining connected to the common venting system properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other
7.Any improper operation of the common venting system should be corrected so the installation conforms with the National Fuel Gas Code, NFPA 54/ANSI Z223.1. When resizing any portion of the common venting system, the common venting system should be resized to approach the minimum size as determined using the appropriate tables in Part 11 in the National Fuel Gas Code, NFPA 54/ ANSI Z223.1.
Figure 30: Typical Vent Installation
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