CAUTION

THE WATER HEATER IS POLARITY SENSITIVE. BEFORE APPLYING ELECTRICITY TO THIS HEATER BE CERTAIN THAT SUPPLY NEUTRAL WIRE TO GROUND CHECK INDICATES ZERO VOLTAGE.

HOT SURFACE IGNITER

The Hot Surface Igniter is a device that ignites the main burner by high temperature (>1800°F or >982°C). When 120VAC is applied to the igniter, sufficient heat is generated to ignite the main burner. Although improvements have been made to strengthen the igniter, it is fragile and care must be taken when handling the igniter to prevent breakage.

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 3. The figures shown are for straight lengths of pipe at 0.5 in. W.C. (125Pa) 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.

CAUTION

DO NOT USE FLEXIBLE GAS PIPING.

TABLE 3. MAXIMUM CAPACITY OF PIPE IN CUBIC FEET OF GAS PER HOUR (Based upon a Pressure Drop of 0.5 inch Water Column and 0.6 Specific Gravity Gas and max. gas pressure of 0.5 psig).

 

LENGTH

 

NORMAL IRON PIPE SIZES (INCHES)

 

 

IN

 

INPUT IN THOUSANDS BTU/HR

 

 

FEET

1 1/4"

1 1/2"

2"

2 1/2"

3"

4"

10

1400

2100

3960

6300

11000

23000

20

950

1460

2750

4360

7700

15800

 

30

770

1180

2200

3520

6250

12800

40

660

990

1900

3000

5300

10900

 

50

580

900

1680

2650

4750

9700

60

530

810

1520

2400

4300

8800

 

70

490

750

1400

2250

3900

8100

 

80

460

690

1300

2050

3700

7500

90

430

650

1220

1950

3450

7200

100

400

620

1150

1850

3250

6700

125

360

550

1020

1650

2950

6000

150

325

500

950

1500

2650

5500

 

175

300

460

850

1370

2450

5000

200

 

430

800

1280

2280

4600

LENGTH

 

NORMAL IRON PIPE SIZES (INCHES)

 

IN

 

 

INPUT IN KW

 

 

METERS

1 1/4"

1 1/2"

2"

2 1/2"

3"

4"

3.0

410

615

1160

1845

3221

6735

6.1

278

428

805

1277

2255

4626

9.1

225

346

644

1031

1830

3748

12.2

193

290

556

878

1552

3192

15.2

170

264

492

776

1391

2840

18.3

155

237

445

703

1259

2577

21.3

143

220

410

659

1142

2372

24.4

135

202

381

600

1083

2196

27.4

126

190

357

571

1010

2108

30.5

117

182

337

542

952

1962

38.1

105

161

299

483

864

1757

45.7

95

146

278

439

776

1610

53.3

88

135

249

401

717

1464

61.0

 

126

234

375

688

1347

WARNING

THE HEATER IS NOT INTENDED FOR OPERATION AT HIGHER THAN 11.0" WATER COLUMN (2.74 Kpa) FOR NATURAL GAS AND 14.0" W.C. (3.49kPa) FOR PROPANE GAS SUPPLY PRESSURE. HIGHER GAS SUPPLY PRESSURES REQUIRE SUPPLEMENTAL REDUCING SERVICE REGULATION. EXPOSURE TO HIGHER GAS SUPPLY PRESSURE MAY CAUSE DAMAGE TO THE GAS CONTROLS 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 PROTECTED AGAINST BLOCKAGE. THESE ARE PARTS OF THE GAS SUPPLY SYSTEM, NOT THE HEATER. VENT BLOCKAGE MAY OCCUR DURING ICE STORMS. 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 TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS SUPPLY LINE, A DIRT LEG (SOMETIMES CALLED A SEDIMENT TRAP OR DRIP LEG) MUST BE INCORPORATED IN THE PIPING (SEE FIG. 14). 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 NATIONAL FUEL GAS CODE NFPA

54OR THE NATURAL GAS AND PROPANE INSTALLATION

CODE CAN/CSA-B149.1.

FIGURE 14.

CONNECTION OF GAS PIPE

1.When connecting gas pipe to unit, apply wrench to flange only. Note: Do not use wrench on gas valve or gas bracket.

2.PERFORM THE GAS LEAK TEST ANY TIME WORK IS DONE

ON A GAS SYSTEM TO AVOID THE POSSIBILITY OF FIRE OR

EXPLOSION WITH PROPERTY DAMAGE, PERSONAL INJURY

OR LOSS OF LIFE.

The Gas Leak Test is performed as follows: Paint pipe connections upstream of gas control with a rich soap and water solution to test for leaks before operating main burner. Bubbles indicate gas leak. To stop leak, tighten pipe connections. After piping connections are checked, turn on main burner. With main burner in operation, paint pipe joints (including flanges), pilot gas tubing connections and control inlet and outlet with rich soap and water solution. Bubbles indicate gas leak. To stop leak, tighten flange screws, joints and pipe connections. Replace part if leak can’t be stopped.

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A.O. Smith 300A, 500A warranty GAS Piping, HOT Surface Igniter, Connection of GAS Pipe