At the time of removal of an existing boiler, the following items 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,
or 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 appliances remaining connected to
common venting system are located and other spaces of the building. Turn on clothes dryers and any appliances not connected to common
venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not
operate a summer exhaust fan. Close fireplace dampers.
4. Place in operation the appliance being inspected. Follow the lighting instructions. Adjust thermostat so appliance will operate continuously.
5. Test for spillage at 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 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 common venting system should be corrected so installation conforms with the NFGC. When resizing any portion
of common venting system, common venting system should be resized to approach minimum size as determined using appropriate tables
in Part 11 of the NFGC.
For boilers connected to gas vents or chimneys, vent installations shall be in accordance with Part 7, NFGC Venting of Equipment and applicable
provisions of local building codes.
Vent connectors serving appliances vented by natural draft shall not be connected into any portion of mechanical draft systems operating under
positive pressure.
Fig. 7—Typical Masonry Chimney Requirements
A95144
3/4 HT MAXIMUM
MUST SLOPE UP
AT LEAST 1/4 IN.
PER FT OF
HORIZONTAL RUN
2-FT MIN
HT
3-FT MIN
ROOF RIDGE
—11—