A.O. Smith GDVH Vertical Extension Kit Height, Horizontal Extension Kit, All Installations, Page

VERTICAL (EXTENSION KIT) HEIGHT

It is simple to determine which kit is needed for vertical height. Take the total height (to the top of the flue) required and comparing that to “F DIMENSION” in TABLE 1, it can be determined which kit needs to be used vertically.

WARNING

Obstructions and deteriorated vent systems may present serious health risk or asphyxiation.

FIGURE 12

TABLE 1.

	BTU’s			FDIMENSION
*GAL.	in 1000’s	900068-7	900124-6		900124-7		900124-8
CAP.	NAT/L.P.	STD.	MIN.	MAX.	MIN.	MAX.	MIN.	MAX.
40	36/36	63-3/4	72	77	77	88	88	110
50	38/38	72	80-3/4	86	86-1/4	97-1/4	97-1/4	118-3/4
40	40/40	63-3/4	72	77	77	88	88	110
50	48/44	76	84-1/4	89-3/4	89-3/4	100-3/4	100-3/4	122-3/4
75	55 NAT.	76-1/4	84-1/2	89-1/2	89-1/2	100-1/2	100-1/2	122-1/2

*See models and rating plate attached to the water heater for specific model number and other detailed information.

HORIZONTAL (EXTENSION KIT)

To determine the horizontal length and extension kit needed, simply plug the dimensions “D” and “G” into the equation below. The answer “E” should then be located in TABLE 2. The size range in which “E” dimension falls indicates the kit that should be used horizontally to obtain the desired length.

EQUATION: D + G = E

“D” = The wall thickness

“G” = The distance wanted between the edge of the water heater and the inside edge of the wall

“E” = The distance the extension kit must be able to extend

TABLE 2.
					E DIMENSIONS
VENT KITS			40-50 Gal.			75 Gal.
			MIN.		MAX.	MIN.	MAX.
900068-7-STD.			3-1/2		10	7/8	7-3/8
900124-6			10		15-1/2	7-3/8	12-7/8
900124-7			15-1/2		26-1/2	12-7/8	23-7/8
900124-8			26-1/2		48	23-7/8	45-3/8
*GAL.	*BTU’S in
		1000’s			A	B	C
CAP.		NAT/L.P.
40		36/36		48-3/4		41-3/4	21
50		38/38		57-1/2		50-1/2	21
40		40/40		48-3/4		41-3/4	21
50		48/44		61		54	21
75		55 NAT.		63		54-3/4	26-1/4

*See models and rating plate attached to the water heater for specific model number and other detailed information.

WARNING

Be sure vent pipe is properly connected to prevent escape of dangerous flue gases which could cause deadly asphyxiation.

ALL INSTALLATIONS

For ease of assembly the installation of the various kit combinations has been broken into individual sections. The two steps below are common to all installations. Once these have been performed, you need only to refer to the type installation that pertains to you.

Installation Using Vent Kits:

1.	Standard Vent Kit	Page 8
2.	Optional Vertical Vent Kit	Page 10
	with Standard Vent Kit
3.	Optional Horizontal Vent Kit	Page 13
4.	Optional Horizontal and	Page 15
	Vertical Vent Kits

CUTTING THE OPENING THROUGH

THE OUTSIDE WALL

After thoroughly reading the “Locating the New Water Heater” section of this manual and you have chosen a suitable water heater installation site, use the chart below to determine dimensions for the opening in the wall.

Cut a 61/4” diameter hole completely through the outside wall.

FIGURE 13

8