PB Heat 211A - Manual (Page 8)

PREINSTALLATION
3. Chimney/Vent Operation: The vent system must be
sized and installed to provide the draft needed to
remove all combustion products. If the vent system
does not provide enough draft, combustion products
will spill into the building from the draft hood relief
opening. If spillage of combustion products occurs,
check the vent system, the combustion and
ventilation openings and make sure the boiler room
is never under negative pressure.
4. Exterior Vents
a. If the vent is outside, make sure it is insulated
sufficiently to ensure adequate draft.
5. Vent Sizing:
a. Individual vents: Use vent piping the same
diameter as the boiler vent connection. The
minimum height is 10 feet (305 cm) above the
bottom of the draft hood (relief opening). The
vent must also extend above the roof or any
obstructions as outlined in the current edition of
the National Fuel Gas Code, ANSI Z223.1/NFPA
54 and/or CAN/CGA B149, Installation Codes or
as required by local codes.
b. Combined vent breeching:
• The recommended sizing in Section 14, Boiler
Ratings & Dimensions, in this Manual is based
on a minimum chimney or vent height of 20
feet (610 cm) and a maximum horizontal run
of 6 feet (183 cm) to the chimney with no
more than one 90-degree standard elbow.
• The minimum area of the chimney serving
two or more appliances must be at least the
area of the largest chimney connector plus
50% of the total area of all other appliance
connectors.
• The vent connector must be single wall steel
or Type B double wall vent pipe. The vent
connector must be Type B double wall if it is
located in or passes through cold areas. The
vent connector must extend into, but not
beyond, the inside wall of the chimney.
6. Vent Connection to Boiler (Figure 1.8):
a. Provide at least a 3 foot (91 cm) rise in the vent
connection on the boiler.
b. The vent system should provide a draft of at least
0.02" w.c. (5 Pa) measured at the vent
connections.
c. Support the weight of the vent system
independently of the boiler draft hood. The draft
hood is not designed to carry structural loading.
d. Provide support of the vent connector
(breeching) at maximum 12 foot (366 cm)
intervals to prevent sagging and to provide a
minimum upward slope of 1/4" per foot (21 mm
per meter).
e. Do not connect the vent for this boiler into any
vent system which operates with positive
pressure.
f. Use Type B double-wall pipe for vents which run
through unheated spaces.
7. Removing an existing boiler from a common vent:
At the time for removal of an existing boiler, the
following steps shall be followed with each appliance
connected to the common venting system placed in
operation, while the other appliances remaining
connected to the common venting system are not in
operation.
a. Seal any unused openings 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 appliance 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 exhaust fan. Close fireplace dampers.
d. Place in operation the appliance being inspected.
Follow the lighting instructions. Adjust the
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.
Failure to provide adequate venting can result in
severe property damage, personal injury or death.
WARNING
Figure 1.8: Vent Connection
6