A.O. Smith BTP(V)-540A, 650A, 740A warranty GAS Piping, Drain Valve and Access Panels

5.Attach a properly sized length of Selkirk Metalbestos model PS or model G venting to the exhaust vent adapter using the inner vee bands, see Figures 7 and 7B on page 10.

6.Fill the grooves in both inner vee bands with high-temp silicone sealant, Dow Corning 736 or equivalent.

7.Position the inner vee bands around the inner pipe flanges and tighten the screws securing the bands.

8.Align the outer channel band with the outer pipe grooves and tighten the screws securing the bands.

9.Repeat steps 6-8 for each successive pipe length until the venting reaches the heater.

10.Follow the manufacturer’s instructions for proper support and guide spacing for horizontal runs of pipe, see Table 6.

WARNING

PRIMERS AND CEMENTS ARE EXTREMELY FLAMMABLE, AND MUST NOT BE STORED OR USED NEAR HEAT OR OPEN FLAME. ALLOWADEQUATECURINGTIMEBEFOREOPERATINGHEATER.

DRAIN VALVE AND ACCESS PANELS

The heaters are equipped with a 3/4” NPT drain valves mounted above and to the left of the burner.

An access panel is located above and to the right of the burner, see Figure 8. This panel covers the cleanout opening in the tank which is sealed by a gasket and cover. Another cleanout access panel is located towards the back of the heater.

TABLE 6.

Vent Diameter	S	F
8” - BTPV -540A, 650A & 740A	15’ 3”	7’ 6”

S = Maximum spacing between two guides or a support and a guide in either a vertical or horizontal direction.

F = Maximum height above a guide or support for free standing system above a roof or parapet wall.

11.Use an expansion joint between any two fixed points in the exhaust venting system wherever the expansion may exceed 1/4”. Selkirk Metalbestos model PS and model G venting will expand by one inch per 100°F in gas temperature per 100 feet of vent length. The expansion can be calculated by the following formula:

Expansion,	Vent length between	5
=	two fixed points, feet	x
Inches		100

If the expansion calculated is greater than 1/4”, an expansion joint must be used between the two fixed points.

12.Attach the flue reducer included in the exhaust vent hood package to the flue collar on the heater.

13.Attach the flue reducer to the vent system using a seal ring. Attach this ring to the venting using the inner vee bands as outlined in Steps 5-7.

14.Attach 8” air-intake connector to intake vent hood collar. It may be necessary to use a slip-slip coupling to fit the pipe to the intake vent hood.

15.Attach 8” air-intake connector back to the 6” burner air inlet with 8” x 6” reducer. Prime and cement each joint to assure gas-tight construction.

16.Seal all joints at the vent hoods with silicone sealant. Also seal the joints at the flue collar and air inlet adapter. Joint on the exhaust side must be sealed with high-temp silicone sealant, Dow Corning 736 or equivalent.

FIGURE 8.

GAS PIPING

Contact your local gas service company to ensure that adequate gas service is available and to review applicable installation codes for your area.

Size the main gas line in accordance with Table 9 and 9A. Minimum required gas supply pipe size is 1 1/4”. The figures shown are for straight lengths of pipe at 0.5 in. w.c. pressure drop, which is considered normal for low pressure systems. Note that fittings such as elbows and tees will add to the pipe pressure drop.

TABLE 9

MAXIMUM CAPACITY OF PIPE IN CUBIC FEET OF GAS PER HOUR

(Based upon a Pressure Drop of 0.5 inch Water Column and 0.5 Specific Gravity Gas and max. gas press. of .5 psig)

LENGTH
IN			Nominal Iron Pipe Sizes, Inches
FEET	1/2"	3/4"	1"	1 1/4"	1 1/2"	2"	2 1/2"	3"	4"
10	175	360	680	1400	2100	3960	6300	11000	23000
20	120	250	485	950	1460	2750	4360	7700	15800
30	97	200	375	770	1180	2200	3520	6250	12800
40	82	170	320	660	990	1900	3000	5300	10900
50	73	151	285	580	900	1680	2650	4750	9700
60	66	138	260	530	810	1520	2400	4300	8800
70	61	125	240	490	750	1400	2250	3900	8100
80	57	118	220	460	690	1300	2050	3700	7500
90	53	110	205	430	650	1220	1950	3450	7200
100	50	103	195	400	620	1150	1850	3250	6700
125	44	93	175	360	550	1020	1650	2950	6000
150	40	84	160	325	500	950	1500	2650	5500
175	37	77	145	300	460	850	1370	2450	5000
200	35	72	135	280	430	800	1280	2280	4600

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