Lennox Hearth L20 DVF-2 manual MODEL L20 BF-2ONLY, B-VentInstallation Illustration

INSTALLATION

MODEL L20 BF-2 ONLY

This appliance is designed to be vented with a 4” B-Vent pipe. Each B-Vent appliance must use its own separate vent system. For pipe clearances, also see pipe manufacturers venting instructions.

B-Vent Installation Illustration

Approved for vertical termination only.

	Vertical
	Termination
Firestops must be	Only
used when vent
pipe passes
through a floor or
ceiling

Horizontal runs	25
	Feet
require ¼” rise
	Max.
per foot.

See chart

5 Feetbelow to

Min.determine horizontal run allowed

Model L20 BF-2

Maximum Horizontal Pipe Runs

for Given Vertical Pipe Run (in feet)

Vertical run	5’	6’	8’	10’	15’	20’
in feet
Maximum horizon-	4’	6’	8’	10’	15’	20’
tal run in feet

Note: Maximum allowable horizontal pipe run is 20 feet.

Vent Configuration Requirements

A minimum of 5 feet vertical pipe is required to vent the ap- pliance. Lengthy horizontal pipe runs require sufficient length of vertical pipe to deliver adequate draft. Use the table above as a guide in planning your installation. The use of multiple 45° or 90° elbows should be compensated by providing addi- tional vertical pipe run.

The B-Vent unit has a 4” B-Vent flue collar and may be in- stalled with listed B-Vent piping and components. Refer to the pipe manufacturer’s installation instructions for specific requirements for their product. Maintain proper clearances to combustible materials as specified by the pipe manufacturer. Whenever vent pipe is run horizontally, maintain a minimum 1/4” rise per foot. Exterior B-Vent exhaust systems should be enclosed in a chase to avoid rapid cooling of exhaust gases in the vent. Such cooling could produce condensation of flue gases or exhaust gas spillage. The use of a chase is highly recommended in colder climates.

Notes:

Maximum total offsets allowed: Not to exceed 180 de- grees.

Also see pipe manufacturers instructions for additional vent installation requirements.

Horizontal vent clearances: 3“ minimum top, 1“ mini- mum on bottom and sidewalls.

Vertical vent clearances: 1” minimum.

Install vent support brackets every 4 feet of vertical pipe unless otherwise specified by vent manufacturer.

For vent termination requirements, see page 10

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