A.O. Smith BT- 80 warranty GAS Piping and Dirt LEG Installation GAS Meter Size

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 1. 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: Fittings such as elbows, tees and line regulators will add to the pipe pressure drop. Also refer to the current editions of the National Fuel Gas Code or Natural Gas and Propane Installation Code.

WARNING

THE HEATER IS NOT INTENDED FOR OPERATION AT HIGHER THAN 14.0" W.C.(3.48 kPa) - NATURAL GAS OR 14.0" W.C. (3.48 kPa) PROPANE GAS SUPPLY PRESSURE. EXPOSURE TO HIGHER SUPPLY PRESSURE MAY CAUSE DAMAGE TO THE GAS VALVE WHICH COULD RESULT IN FIRE OR EXPLOSION. IF OVERPRESSURE HAS OCCURRED SUCH AS THROUGH IMPROPER TESTING OF GAS LINES OR EMERGENCY MALFUNCTION OF THE SUPPLY SYSTEM, THE GAS VALVE MUST BE CHECKED FOR SAFE OPERATION. MAKE SURE THAT THE OUTSIDE VENTS ON THE SUPPLY REGULATORS AND THE SAFETY VENT VALVES ARE PROTECTEDAGAINST BLOCKAGE. THESE ARE PARTS OF THE GAS SUPPLY SYSTEM, NOT THE HEATER. VENT BLOCKAGE MAY OCCUR DURING ICE STORMS.

TABLE 1 - GAS SUPPLY LINE SIZES (IN INCHES)*

MAXIMUM CAPACITY OF PIPE IN

CUBIC FEET PER HOUR

LENGTH			NOMINAL IRON PIPE SIZES (INCHES)
IN			INPUT IN THOUSANDS (BTU/HR)
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		465		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
LENGTH			NOMINAL IRON PIPE					SIZES (INCHES)
IN			INPUT IN KW
METERS	1/2"		3/4"		1"	1 1/4"	1 1/2"	2"	2 1/2"	3"	4"
3	51		105		199	410	615	1160	1845	3221	6735
6	35		73		142	278	428	805	1277	2255	4626
9	28		59		110	225	346	644	1031	1830	3748
12	24		50		94	193	290	556	878	1552	3192
15	21		44		83	170	264	492	776	1391	2840
18	19		40		76	155	237	445	703	1259	2577
21	18		37		70	143	220	410	659	1142	2372
24	17		35		64	135	202	381	600	1083	2196
27	16		32		60	126	190	357	571	1010	2108
31	15		30		57	117	182	337	542	952	1962
38	13		27		51	105	161	299	483	864	1757
46	12		25		47	95	146	278	439	776	1610
53	11		23		42	88	135	249	401	717	1464
61	10		21		40	82	126	234	375	688	1347

IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING FROM CONTAMINANTS IN THE GAS WAYS. SUCH FOULING MAY CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.

IF COPPER SUPPLY LINES ARE USED THEY MUST BE INTERNALLY TINNED AND CERTIFIED FOR GAS SERVICE. BEFORE ATTACHING THE GAS LINE, BE SURE THAT ALL GAS PIPE IS CLEAN ON THE INSIDE.

TO TRAPANY DIRT OR FOREIGN MATERIAL IN THE GAS SUPPLY LINE,ADIRT LEG (SOMETIMES CALLED SEDIMENT TRAPOR DRIP LEG) MUST BE INCORPORATED IN THE PIPING (SEE FIG. 5). THE DIRT LEG MUST BE READILY ACCESSIBLE AND NOT SUBJECT TO FREEZING CONDITIONS. INSTALL IN ACCORDANCE WITH RECOMMENDATIONS OF SERVING GAS SUPPLIERS. REFER TO THE CURRENT EDITION OF THE NATIONALFUEL GAS CODE OR NATURAL GAS AND PROPANE INSTALLATION CODE.

To prevent damage, care must be taken not to apply too much torque when attaching gas supply pipe to gas valve inlet.

Apply joint compounds (pipe dope) sparingly and only to the male threads of pipe joints. Do not apply compounds to the first two threads. Use compounds resistant to the action of liquefied petroleum gases.

BEFORE PLACING THE HEATER IN OPERATION, CHECK FOR GAS LEAKAGE. Use soap and water solution or other material acceptable for the purpose in locating the leaks. DO NOT USE

MATCHES, CANDLES, FLAME OR OTHER SOURCES OF IGNITION FOR THIS PURPOSE.

DISCONNECT THE HEATER AND ITS MANUAL GAS SHUTOFF VALVE FROM THE GAS SUPPLY PIPING SYSTEM DURING ANY SUPPLY PRESSURE TESTING EXCEEDING 1/2 PSIG (3.45 kPa).

GAS SUPPLY LINE MUST BE CAPPED WHEN DISCONNECTED FROM THE HEATER FOR TEST PRESSURES OF 1/2 PSIG (3.45 kPa) OR LESS. THE APPLIANCE NEED NOT BE DISCONNECTED, BUT MUST BE ISOLATED FROM THE SUPPLY PRESSURE TEST BY CLOSING THE MANUAL GAS SHUTOFF VALVE.

FIGURE 5 - GAS PIPING AND DIRT LEG INSTALLATION

GAS METER SIZE

Be sure the gas meter has sufficient capacity to supply the full rated gas input of the water heater as well as the requirements of all other gas fired equipment supplied by the meter. If gas meter is too small, ask the gas company to install a larger meter having adequate capacity.

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