UIM-C-0712, Vent System, Venting Multiple Units

701379-UIM-C-0712

VENT SYSTEM

This furnace is certified to be installed with one of two possible vent configurations.

1.Horizontal vent system. This vent system can be installed com- pletely horizontal or combinations of horizontal, vertical, or offset using elbows.

2.Vertical vent system. This vent system can be installed completely vertical or a combination of horizontal, vertical, or offset using elbows.

VENT APPLICATIONS AND TERMINATION

When selecting the location for a combustion air / vent termination, the following should be considered:

1.	Observe all clearances listed in vent clearances in these instruc-
	tions.
2.	Termination should be positioned where vent vapors will not dam-

12” MIN.

12” Minimum below overhang

12” Minimum separation between bottom of combustion air intake and bottom of vent

Maintain 12” minimumclearance above highest anticipated snow level or grade, whichever is higher

	age plants or shrubs or air conditioning equipment.
3.	Termination should be located where it will not be affected by wind
	gusts, light snow, airborne leaves or allow recirculation of flue
	gases.
4.	Termination should be located where it will not be damaged or
	exposed to flying stones, balls, etc.
5.	Termination should be positioned where vent vapors are not objec-
	tionable.
6.	Horizontal portions of the vent system must slope upwards and be
	supported to prevent sagging.
7.	Direct vent systems must be installed so the vent and the combus-
	tion air pipes terminate in the same atmospheric zone. Refer to Fig-
	ures 31 or 32.

Maintain 12” minimum clearance above highest anticipated snow level. Maximum 24” above roof.

12” Min.

FIGURE 30: Termination Configuration - 1 Pipe

FIGURE 32: Termination Configuration - 2 Pipe Basement

VENTING MULTIPLE UNITS

Multiple units can be installed in a space or structure as either a single pipe configuration or a two-pipe configuration.

The combustion air side of the single pipe configuration shown in Figure 30 is referred to in these instructions as ambient combustion air supply. Follow the instructions for ambient combustion air installations, paying particular attention to the section on air source from inside the building. The vent for a single pipe system must be installed as specified in the venting section of these instructions with the vent terminating as shown in Figure 30. Each furnace must have a separate vent pipe. Under NO circumstances can the two vent pipes be tied together.

The combustion air side of the two-pipe configuration shown in Figure 31 can be installed so the combustion air pipe terminates as described in outdoor combustion air or ventilated combustion air sections in these instructions. Follow the instructions for outdoor combustion air or venti- lated combustion air and the instructions for installing the vent system with the vent terminating as shown in Figures 33 or 34. The two-pipe system must have a separate combustion air pipe and a separate vent pipe for each furnace. Under NO circumstances can the two combus- tion air or vent pipes be tied together. The combustion air and vent pipes must terminate in the same atmospheric zone.

VENT

Maintain 12” minimum clearance above highest anticipated snow level.

	12” vertical separation
	between combustion air	12” minimum
	intake and vent.	12” minimum
	intake and vent.	below overhang
		below overhang
		12” minimum
		separation between
		bottom of
		combustion air pipe
		and bottom of vent.
		Maintain 12”
		minimum clearance
		above highest
		anticipated snow
		level or grade,
		whichever is higher.