Lochinvar WH 55-399 operation manual Alternate vertical concentric venting, Vent / Air Inlet Size

5 Vertical direct venting

Alternate vertical concentric venting

Installation & Operation Manual

Figure 5-8Concentric Vent Example 1

FLUE EXHAUST

This appliance may be installed with a concentric vent arrangement where the vent pipe is routed through an existing unused venting system; or by using the existing unused venting system as a chase for vent and combustion air routing.

Concentric Venting Arrangement

The venting is to be vertical through the roof. The annular space between the O.D. of the vent pipe and the I.D. of the existing unused venting system is utilized for the combustion air source.

The minimum size of the existing vent system required to achieve enough annular space for combustion air can be found in Table 5A.

The upper and lower termination as well as any other unsealed joints in the existing vent system must be sealed to ensure that all combustion air is drawn from under the vent cap as shown in FIG.’s 5-8 and 5-9.

Approved venting materials must be used as specified in Table 3D on page 19.

Follow all vent / air termination and clearance requirements per this section to the appropriate example. Installation must comply with local requirements and with the National Fuel Gas Code.

The maximum allowable equivalent vent and air intake lengths for this venting arrangement are to be determined from the General Venting Section.

If an existing unused venting system is converted for use with this method of concentric venting, the installer must ensure that the existing venting system is clean and free from particulate contamination that will harm this appliance and cause increased nuisance calls or maintenance. See Table 1A on page 10 for a list of corrosive contaminants and sources.

Two example scenarios of a concentric venting arrangement are shown for illustrative purposes in FIG.’s 5-8 and 5-9.

Table 5A Alternate Vertical Concentric Vent / Chase Sizes

Vent / Air Inlet Size	Minimum Existing
	Vent / Chase Size
2"	4"
3"	5"
4"	7"

	SEAL
	COMBUSTION AIR
	AIR INLET
EXISTING	W/ SCREEN
	12”
	MIN.
SEAL
SEALED
CAP
FLUE OUTLET

*For concept illustration only. Individual installations

may vary due to job site specific equipment.

Figure 5-9Concentric Vent Example 2

SEAL FLUE EXHAUST

COMBUSTION AIR

SEAL

EXISTING

SEAL

SEALED

CAP

FLUE OUTLET

*For concept illustration only. Individual installations may

vary due to job site specific equipment.

Existing vent as a chase

Follow all existing termination and clearance requirements and allowable pipe lengths. Use only approved venting materials listed in the General Venting Section of this manual.

Figure 5-10Existing Vent as a Chase

FLUE EXHAUST

AIR INLET

SEAL

EXISTING

CAP

SEAL

FLUE OUTLET

	*For concept illustration only. Individual installations
32	may vary due to job site specific equipment.