Horizontal Venting
Vent and combustion air intake terminations must be as shown in Figure 19 unless the concentric vent termination kit is used.
!WARNING:
Ensure that the combustion air vent and the exhaust vent are configured as shown in Fig. 19. Improper vent termination can cause recirculation of the flue gases. This may result in furnace vibration. In severe cases, the furnace will cycle, due to the intermittent contact between the flame and the flame sensor. If you note these oscillations occurring, check the vent configuration. Make sure that the exhaust vent does not have a 90 degree termination.
For horizontal venting, either the Horizontal Exterior Vent Mounting Kit or the Concentric Vent Termination Kit may be used (See Table 12).
For Canadian installations please refer to the Canadian Installation Code
The Horizontal Exterior Vent Mounting Kit con- sists of two face plates and an insulating gas- ket to seal the exterior surface. A hole sized closely to the pipe diameter must first be cut through the wall. A short length of pipe is then cut such that it can penetrate the wall and be held in place by closely fitting standard cou- plings. The face plates are retained on both sides of the wall by the couplings, and the gasket is retained against the wall by the outer face plate. Face plates must be fastened to the wall and the outside one must be flashed as appropriate to prevent entry of water.
When the above kits are not used the following steps are required:
1.Check the hole size cut through the exte- rior wall. Insure that the hole diameter is less than the diameter of the couplings to be used.
2.Extend the vent pipe through the wall approximately 1" and seal the area be- tween the wall and pipe.
3.Apply couplings to the vent pipe on the interior and exterior sides of the wall to insure the pipe can not be pushed or pulled through the wall.
4.Insure the combustion air inlet pipe has a 90 degree termination elbow, and is pointing downward as shown in Figures 19 & 20.
Note that a combustion air intake must be provided with an elbow opening downward.
When the vent pipe must exit an exterior wall close to the grade or expected snow level, a riser should be provided as shown in Figure 18. Insulation is required to prevent freezing of this section of pipe.
Vertical Venting
For vertical venting, either the configuration shown in Figure 20 or the Concentric Vent Termination Kit may be used. Vertical venting is one of the shortest routing methods when piping vents for furnaces. The M3 furnace operates
•The inlet for the combustion intake pipe must be extended at least one foot above the roofline or snow accumulation level.
•The outlet of the vent must be extended at least 10 inches above the inlet of the combustion air intake pipe.
•The vent as well as the combustion air intake
pipe should be located on the same side of the roof. Both pipes must not be closer than 5 inches apart. They should not be separated more than 36 inches.
The roof penetration must be properly flashed and waterproofed with a plumbing roof boot or equivalent flashing. Termination spacing re- quirements from the roof and from each other must be per Figure 20.
Concentric Vent Termination
A concentric vent termination is approved for use with these furnaces (See Table 12). For proper installation of the concentric vent termi- nation, follow the installation instructions pro- vided with the kit.
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