Filter
Top Products
On a conventionally vented, negative draft ap pli ance,
the connection from the vent to the chimney or vent
termination on the outside of the building MUST be
made with listed Type “B” double wall (or equivalent)
vent connectors and must be direct as possible with no
reduction in diameter. Use the National Fuel Gas Code
venting tables for dou ble wall vent to properly size all
vent connectors and stacks. The Type “B” vent and
accessories, such as firestop spacers, thim bles, caps,
etc., MUST be installed in accordance with the
manufacturer’s list ing. The vent connector and firestop
must provide correct spacing to combustible surfaces
and seal to the vent connector on the upper and lower
sides of each floor or ceiling through which the vent
connector passes.
Any vent materials used must be listed by a na tion al ly
recognized test agency for use as vent ma te ri al.
Locate appliance as close as possible to a chimney or
gas vent.
Avoid long horizontal runs of the vent pipe, 90° el bows,
reductions and restrictions. Horizontal por tions of the
venting system shall be supported to prevent sagging.
Horizontal runs must slope up wards not less than 1/4
inch per foot (21 mm/m) from the appliance to the vent
terminal. Follow manufacturer’s instructions.
Do not use an existing chimney as a raceway for a flue
pipe if another appliance or fireplace is vented through
the chimney.
The weight of the venting system must not rest on the
appliance. Adequate support of the venting sys tem must
be provided in compliance with local codes and other
applicable codes. All connections should be secured
with rustproof sheet metal screws.
Vent connectors serving appliances vented by nat u ral
draft shall not be connected to any portion of a
me chan i cal draft system operating under positive
pres sure. Connection to a positive pressure chim ney
may cause flue products to be discharged into the living
space causing serious health injury.
Common venting systems may be too large when an
existing appliance is removed. At the time of removal
of an existing appliance, the following steps shall be
followed with each appliance remaining connected to
the common venting system placed in operation, while
other appliances remaining con nect ed to the common
venting system are not in operation.
(a) Seal any unused opening in the common
venting system.
(b) 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.
(c) 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 other appliances not connected
to the 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 ex -
haust fan. Close fireplace dampers.
(d) Place in operation the appliance being
inspected. Follow the lighting instructions.
Adjust thermostat so appliance will operate
continuously.
(e) 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.
(f) 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 other gas burning
ap pli anc es to their previous conditions of use.
(g) Any improper operation of the common
venting system should be corrected so that the
installation conforms to the latest edition of the
Na tion al Fuel Gas Code, ANSI Z223.1. In
Canada, the latest edition of CGA Standard
B149 Installation Code for Gas Burning
Appliances and Equipment. When resizing any
por tion of the common venting system, the
common venting system should be resized to
ap proach the min i mum size as determined
using the appropriate tables in Part 11 in the
latest edition of the National Fuel Gas Code,
ANSI Z223.1. In Canada, the latest edition of
CGA Stan dard B149 Installation Code for Gas
Burning Appliances and Equipment.
8