INSTALLATION AND OPERATION INSTRUCTIONS
1-12
SL 35-199, SL 45-260 MODULATING GAS BOILERS
EXHAUST PIPE SIZE MAXIMUM EQUIVALENT LENGTH
Sched.40; Rigid PPs
3” 200’
4” 200’
90° long sweep elbow allow 5’ equivalent
90° vent elbow allow 8’ equivalent
45° elbow allow 3’ equivalent
PPs 87-90° elbows use 8’ equivalent
Flexible PPs
3” Flexible (SL 35-199) 160’ (max.) actual lineal x 1.2 = equivalent
3” PPs Flexible (SL 45-260) 60’ (max.) actual lineal x 3.33 = equivalent
4” Flexible 160’ (max.) actual lineal x 1.2 = equivalent
Table 4: Maximum exhaust venting length.
For the inlet air – Schedule 40 PVC, CPVC, ABS or PPs piping of any type is
permitted. Use same diameter as Vent pipe.
NOTE: It is not permitted to add to the exhaust length by transfer of unused
intake allowance.
Combustion air piping - if used - is inserted directly into the 3” female stainless
steelttingonthetop,rightsideoftheboilerandrunhorizontallyorverticallyto
the outdoors. Screen material can be placed at the inlet as appropriate for the
environment (e.g. insects, dust).
Care must be taken to ensure adequate separation is maintained between the
airintakeinletandtheventterminal.Refertotheventterminalconguration
drawings in the Vent Termination section above.
Support should be provided for intake piping, particularly so for horizontal runs
(follow local code).
WARNING
When using Indoor
Air options, adequate
combustion air must be
supplied to the boiler room
according to the requirements
of all applicable codes.
Figure 13: Indoor combustion air intake