3
General venting
16
Minimum / Maximum allowable combustion
air and vent piping lengths are as follows:
Combustion Air
= 7 equivalent feet minimum / 100 equivalent
feet maximum
Vent
= 7 equivalent feet minimum / 100 equivalent feet
maximum
When determining equivalent combustion air and vent length,
add 5 feet for each 90° elbow and 3 feet for each 45° elbow.
EXAMPLE:
20 feet of PVC pipe + (4) 90° (2) 45°
(1) concentric vent kit (100140480) = 49 equivalent
feet of piping.
The appliance output rating will reduce by
up to 1.5% for each 25 feet of vent length.
NOTICE
Model
Kit
Number
Equivalent Vent
Length
Vent
Size
110 - 150
100140485
3 feet
2 inch
110 - 199
100140480
3 feet
3 inch
Table 3B Concentric Vent Kit Equivalent Vent Lengths
Sizing
The Noble Combi Boiler uses model specific combustion air
intake and vent piping sizes as detailed in Table 3A below.
Table 3A Air Intake/Vent Piping Sizes
Increasing or decreasing combustion air
or vent piping sizes is not authorized.
NOTICE
Model
2" Max Vent/Air 3" Max Vent/Air
110
100 feet
100 feet
150
60 feet
100 feet
199
N/A
100 feet
Installation & Service Manual
Materials
Air inlet pipe materials:
The air inlet pipe(s) must be sealed. Choose acceptable
combustion air inlet pipe materials from the following list:
PVC, CPVC, Polypropylene or ABS
Galvanized steel vent pipe with joints and seams sealed as
specified in this section.
Type “B” double-wall vent with joints and seams sealed as
specified in this section.
AL29-4C, stainless steel material to be sealed to
specification of its manufacturer.
*Plastic pipe may require an adapter (not provided) to
transition between the air inlet connection on the appliance
and the plastic air inlet pipe.
WARNING
Using air intake materials other than those
specified can result in personal injury,
death or property damage.
NOTICE
The use of double-wall vent or insulated
material for the combustion air inlet pipe is
recommended in cold climates to prevent
the condensation of airborne moisture in
the incoming combustion air.
Sealing of Type “B” double-wall vent material or galvanized
vent pipe material used for air inlet piping on a sidewall or
vertical rooftop Combustion Air Supply System:
a. Seal all joints and seams of the air inlet pipe using either
Aluminum Foil Duct Tape meeting UL Standard 723 or
181A-P or a high quality UL Listed silicone sealant such as
those manufactured by Dow Corning or General Electric.
b. Do not install seams of vent pipe on the bottom of
horizontal
runs.
c. Secure all joints with a minimum of three (3) sheet metal
screws or pop rivets. Apply Aluminum Foil Duct Tape or
silicone sealant to all screws or rivets installed in the vent
pipe.
d. Ensure that the air inlet pipes are properly supported.
The PVC, CPVC, or ABS air inlet pipe should be cleaned and
sealed with the pipe manufacturer’s recommended solvents
and standard commercial pipe cement for the material used.
The PVC, CPVC, ABS, or Flex Duct air inlet pipe should
use a silicone sealant to ensure a proper seal at the appliance
connection and the air inlet cap connection. Dryer vent or
flex duct should use a screw type clamp to seal the vent to
the appliance air inlet and the air inlet cap. Proper sealing of
the air inlet pipe ensures that combustion air will be free of
contaminants and supplied in proper volume.
When a sidewall or vertical rooftop combustion air supply
system is disconnected for any reason, the air inlet pipe
must be resealed to ensure that combustion air will be free of
contaminants and supplied in proper volume.
DANGER
Failure to properly seal all joints and seams
as required in the air inlet piping may
result in flue gas recirculation, spillage
of flue products and carbon monoxide
emissions causing severe personal injury
or death.
F I R E T U B E C O M B I
™
