A.Vent Guidelines Due to Removal of an Existing Boiler
For installations not involving the replacement of an existing boiler, proceed to Step B.
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 remaining appliances. 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 five (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 gas burning appliance to their previous conditions of use.
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 II in the National Fuel Gas Code, NFPA 54/ ANSI Z223.1.
B.General Guidelines
1.Vent system installation must be in accordance with National Fuel Gas Code, NFPA 54/ANSI Z221.3 or applicable provisions of local building codes. Contact local building or fire officials about restrictions and installation inspection in your area.
2.Refer to the appropriate drawings in this section of this manual to determine the proper configuration of venting system. See Table 1.
3.This appliance requires a Special Gas Vent. The
4.Horizontal vent pipe must maintain a minimum ¼ inch per foot slope away from boiler.
5.Use noncombustible ¾ inch pipe strap to support horizontal runs and maintain vent location and slope while preventing sags in pipe. Do not restrict thermal expansion or movement of vent system.
Maximum support spacing is five (5) feet. Do not penetrate any part of the vent system with fasteners.
6.Vent length restrictions are based on equivalent length of vent pipe (total length of straight pipe plus equivalent length of fittings). Maximum vent lengths are listed in Table 4. Do not exceed maximum vent lengths. Table 3 lists equivalent lengths for fittings. Do not include vent terminals in equivalent feet calculations.
7.Provide and maintain vent pipe minimum clearances to combustible materials. Vent pipe minimum clearance to combustible material is four (4) inches when vent is installed in a fully enclosed (chase) application or three (3) inches when vent is installed with at least one side open, similar to a joist bay application. Use double wall thimble [Burnham Part No. 8116115 (3”),
8.Do not install venting system components on the exterior of the building except as specifically required by these instructions. The vent termination location is restricted as follows:
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