InsTAllATIon - venTIng
D7. Determine the length of the vent pipe and combustion air
pipe that must be attached to the vent outlet and
combustion air inlet (on the concentric side) of the adapter
box (refer to Figure 9.4 and 10.1) to extend through the
building wall or roof. Be sure to add the length of the field
supplied brackets (if used) and the thickness of the wall or
roof. Note the following when determining the pipe lengths:
for vertical Concentric vent Kits
(refer to figure .2):
• The bottom of the combustion air intake pipe must
terminate above the snow line, or at least 12 inches
above the roof, whichever distance is greater.
• The bottom of the vent cap must terminate at least 6
inches above the top of the combustion air intake cap.
for Horizontal Concentric vent Kits
(refer to figure .3):
• The combustion air intake pipe must terminate at least
1 inch from the wall to prevent water from running down
the wall and into the pipe.
• The back of the vent cap must terminate at least 14
inches from the combustion air intake pipe.
D8. Cut the concentric side vent and combustion air pipes to
the proper length as determined in the previous step. Note
that the vent pipe diameter is 4" and the combustion air
intake pipe diameter is 6" for model sizes 150-200, and 6"
and 8" respectively for model sizes 250-400. Both pipes
must be single wall galvanized or stainless steel material.
D9. Attach the concentric side vent pipe to the vent outlet of
the concentric vent adapter box, as shown in Figure 9.4,
using at least 3 corrosion resistant sheet metal screws.
Seal the joint and seam using sealant suitable for
temperatures up to 400°F.
D10. Slide the combustion air pipe over the vent pipe and
attach to the air inlet of the concentric adapter box, as
shown in Figure 10.1, using at least 3 corrosion resistant
sheet metal screws. Seal the joint and seam using sealant
suitable for temperatures up to 400°F.
figure 10.1 - Adapter Box with Combustion Air
Intake Pipe Attached
Outlet Vent
Pipe Attached
Combustion Air
Intake Guard
D11. Place this assembly (the adapter box, vent pipe and
combustion air pipe) through the wall or roof and verify
that the distance requirements as defined in Step D7 are
met. Securely attach the assembly building.
D12. From outside the building, caulk the gap between the
combustion air intake pipe and the building penetration.
D13. Attach the combustion air intake and vent pipe
terminations as follows:
10
for vertical Concentric vent Kits
(refer to figure .2):
• Slide the combustion air cap down over the vent pipe and
• Attach the vent cap to the vent pipe using at least 3
• Caulk the gap between the combustion air cap and the
for Horizontal Concentric vent Kits
(refer to figure .3):
• Attach the combustion air intake guard using corrosion
• Attach the vent cap to the vent pipe using at least 3
D14. Install vent pipe and combustion air pipe between unit
heater and concentric vent adapter box as outlined in
"Section A – General Instructions – All Units".
D15. Once venting is complete, proceed to the section titled
"Installation - Gas Connections".
Combustion Air
Pipe Attached
6-561
fasten it to the combustion air pipe with at least 3
corrosion resistant sheet metal screws.
corrosion resistant sheet metal screws.
vent pipe with silicone sealant, or other appropriate
sealants suitable for metal to metal contact and for
temperatures up to 400° F.
resistant screws at the end of the combustion air intake
pipe to prevent animals and debris from entering.
corrosion resistant sheet metal screws.
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