Lennox Hearth 775 manual 10

Horizontal Termination

The vent must rise vertically, a minimum of 24" (610 mm) off the top of the appliance for Natural Gas and 36" for Propane Gas before the first elbow.

The horizontal run may extend up to 20 feet ( 6 meters) and include a vertical rise of up to 40 feet (12 meters) - see Figure 13. Horizontal termination must meet the criteria shown in Figures 4 and 5.

¥Approved vent systems must terminate above and including the heavy line in Figure 13.

¥Two 45 degree elbows may be substituted for each single 90 degree elbow.

¥With a rise between 2 feet to 5 feet, one 90 degree or two 45 degree elbows may be used.

Vertical Termination

A vertical vent system must terminate no less than 8 feet ( 2.44 meters) and no more than 40 feet / 12 meters ( above the appliance ßue collar. See Figure 14.

A vertically terminated vent system must also conform to the following criteria:

No more than three 90 degree elbows may be used.

Two 45 degree elbows may be substituted for one 90 degree elbow. No more than six 45 degree elbows may be used.

Vent must rise a minimum of 2 feet before an offset is used.

Termination height must conform to roof clearance as speciÞed in Figure 3

feet)	to the top of the vent pipe
Vertical Run (in	appliance flue collar
	Measure from the

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

May use up to three 90 degree elbows

One 90

degree

elbowUnacceptable Venting Configuration

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

		40
		39
		38
		37
		36
		35
	pipe	34
		33
		32
	vent
		31	Vertical Terminations Must
	the	30
		29	be in this area
	of
		28
	top
		27
feet)	to the
		26
		25
Vertical Run (in	appliance flue collar	24
		23
		22
		21
		20
		19
		18
		17
	the
		16
	from
		15												Unacceptable
		14
	Measure													Venting
		13
														Configuration
		12
		11
		10
		9
		8
		7
		6
		5
		4
		3
		2
		1
		0											11	12	13	14	15	16	17	18	19	20
			1	2	3	4	5	6	7	8	9	10

Figure 13 Horizontal Run (in feet)

Figure 14 Horizontal Run (in feet)

10 NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.