INSTALLATION AND OPERATION INSTRUCTIONS
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SL 10-85 G3, SL 14-115 G3, SL 20-160 G3, SL 30-199 G3 MODULATING GAS BOILERSSL 10-85 G3, SL 14-115 G3, SL 20-160 G3, SL 30-199 G3 MODULATING GAS BOILERS
1.4.7 “Direct Vent” Combustion Air Intake Piping
There are two basic methods of supplying combustion air to an IBC boiler.
The direct vent option uses piping from the outside to supply combustion air directly to the
boiler’s combustion air connection.
Table 4: Maximum intake piping length.
NOTE: It is not permitted to add to the exhaust length by transfer of unused intake
allowance.
WARNING
In addition to preventing
ingestion of chemical
contaminants, care must be
taken to ensure air intake
terminals are not installed in
locations where contamination
might occur due to ingestion of
particulate foreign material (dust,
dirt and debris).
Figure 19: Direct vent combustion air intake
WARNING
Intake air openings must be
congured such that rain or
other forms of moisture cannot
enter the air intake piping
system. Otherwise serious
damage to the boiler may result.
NOTE
Care must be taken when
installing air intake piping to
ensure that a “trap” is not formed
in the piping so as to allow a
build-up of water, and blockage
of intake air.
Such blockage will result in a
boiler safety shut-down.
INTAKE PIPE SIZE MAXIMUM EQUIVALENT LENGTH
Sched.40; Rigid PPs SL 10-85 G3 SL 14-115 G3 SL 20-160 G3 SL 30-199 G3
2"
100' 100' 35’ Not applicable
3" 240' 240' 170’ 150’
90° vent elbow allow 8' equivalent allow 8' equivalent allow 8’ equivalent allow 8’ equivalent
90° long sweep elbow allow 5' equivalent allow 5' equivalent allow 5’ equivalent allow 5’ equivalent
45° elbow allow 3' equivalent allow 3' equivalent allow 3’ equivalent allow 3’ equivalent
PPs 87-90° elbows use 8' equivalent use 8' equivalent use 8’ equivalent use 8’ equivalent
Air Intake Filter (Part #103) allow 8' equivalent allow 8' equivalent
2” Stainless Sidewall Terminal
IBC P/N 180-148 (P-256)
No additional
allowance
No additional
allowance
Not allowed Not allowed
3” Stainless Sidewall Terminal
IBC P/N 180-149 (P-257)
No additional
allowance
No additional
allowance
No additional
allowance
No additional
allowance
Flexible PPs
3” Flexible
45’ (max.) lineal x 3.33
= equivalent
45’ (max.) lineal x 3.33
= equivalent
45’ (max.) actual
lineal x 3.33 =
equivalent
30’ (max.) actual
lineal x 3.3 =
equivalent