Napoleon Fireplaces GD70NT-S, GD70PT-S manual TOP Exit / Horizontal Termination, Definitions

6

DEFINITIONS

for the following symbols used in the venting calcula- tions and examples are:

>- greater than

>- equal to or greater than < - less than

< - equal to or less than

HT - total of both horizontal vent lengths (HR) and offsets (HO) in feet

HR - combined horizontal vent lengths in feet

HO - offset factor: .03(total degrees of offset - 90°*) in feet

VT - combined vertical vent lengths in feet

ELBOW VENT LENGTH VALUES

	feet	inches
1°	0.03	0.5
15°	0.45	6.0
30°	0.9	11.0
45°	1.35	16.0
90°*	2.7	32.0

*the first 90° offset has a zero value and is shown in the formula as -90°

TOP EXIT / HORIZONTAL TERMINATION

when (HT) < (VT)

Simple venting configuration (only one 90° elbow)

FIGURE 4

For vent configurations requiring more than one 90° el- bow, the following formulas apply:

Formula 1: HT < VT

Formula 2: HT + VT < 40 feet

Example 1: 90° H2

FIGURE 5 V2

90°

See graph to determine the required vertical rise VT for the required horizontal run HT.

VERTICAL

RISE IN

FEET

VT

HORIZONTAL VENT RUN PLUS OFFSET IN FEET HT

The shaded area within the lines represents acceptable values for HT and VT .

		90°	H1
		V1
V1	=	3 ft
V2	=	8 ft
VT	= V1 + V2 = 3 + 8 = 11 ft
H1	=	2.5 ft
H2	=	2 ft
HR	= H1 + H2 = 2.5 + 2 = 4.5 ft
HO	= .03(three 90° elbows - 90°) = .03(270° - 90°) = 5.4 ft
HT	= HR + HO = 4.5 + 5.4 = 9.9 ft

HT + VT = 9.9 + 11 = 20.9 ft

Formula 1: HT < VT 9.9 < 11

Formula 2: HT + VT < 40 feet

20.9 < 40

Since both formulas are met, this vent configuration is ac- ceptable.

W415-0434 / C / 03.24.05