GAS CONNECTIONS

WARNING

THE INLET GAS PRESSURE MUST NOT EXCEED THE VALUE SPECIFIED BY THE MANUFACTURER ON THE RATING PLATE (10.5" W.C. - NATURAL GAS, 13.0" W.C. - PROPANE GAS).

EXPOSURE TO HIGHER GAS 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 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 SEDIMENT TRAP OR DRIP LEG), MUST BE INCORPORATED IN THE PIPING. SEE PIPING DIAGRAMS. THE DIRT LEG MUST BE READILY ACCESSIBLE AND NOT SUBJECT TO FREEZING CONDITIONS. INSTALL IN ACCORDANCE WITH RECOMMENDATIONS OF SERVING GAS SUPPLIERS. IN THE UNITED STATES REFER TO ANSI Z223.1-1999 OR MOST RECENT EDITION OF THE NATIONAL FUEL GAS CODE. IN CANADA, THE CANADIAN INSTALLATION CODE CAN/CGA B 149 (LATEST EDITION).

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

Fittings and unions in the gas line must be metal to metal type.

Apply joint compounds (pipe dope) sparingly and only to the male threads of pipe joints. Do not apply compound 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 gas 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 PRESSURE TESTING OF THAT SYSTEM AT TEST PRESSURES IN EXCESS OF 1/2 PSIG. THE GAS SUPPLY LINE MUST BE CAPPED WHEN NOT CONNECTED TO HEATER.

THE HEATER MUST BE ISOLATED FROM THE GAS SUPPLY PIPING SYSTEM BY CLOSING ITS MANUAL GAS SHUTOFF VALVE DURING ANY PRESSURE TESTING OF THE GAS SUPPLY PIPING SYSTEM AT TEST PRESSURES EQUAL TO OR LESS THAN 1/2 PSIG (3.44kPa).

CORRECT GAS

MAKE SURE the gas on which the heater will operate is the same as that specified on the heater model and rating plate. Do not install the heater if equipped for a different type gas - contact the heater supplier.

SIZING GAS SUPPLY LINE

The iron pipe or equivalent pipe sizes in Table 6 are derived from Table C-3 in the NATIONAL FUEL GAS CODE. The pipe sizes are based on a supply line gas pressure drop of 0.3 inches of water column from the gas meter to the point of installation of the heater(s). For natural gas, a heating value of 1050 Btu/ft3 and a specific gravity of 0.60 has been assumed. A heating value of 2500 Btu/ft3 and a specific gravity of 1.53 has been assumed for L.P. (propane) gas.

Where it is necessary to use an excess number of pipe fittings, i.e., elbows, tees and valves, in the gas supply line, use pipe at least one size larger than that recommended in Table 2 to compensate for the increased pressure drop.

If the service pressure is 4.5 inches W.C. (1.12kPa) (11 inches (1.74kPa) for L.P. gas) of water column or less, use pipe size larger than specified in Table 6 to minimize pressure drop in the line.

GAS METER SIZE - City Gases Only

Be sure that the gas meter has sufficient capacity to supply the full rated gas input of the 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.

TABLE 6

GAS SUPPLY PIPE SIZES (IN INCHES)

Distance To Heater

 

NATURAL GAS (1050 Btu/ft3)

 

 

PROPANE GAS (2500 Btu/ft3)

 

 

 

 

 

 

 

 

 

From Meter (FT./M)

HW-120M

HW-160M

HW-200M

HW-225M

 

HW-120M

HW-160M

HW-200M

10 (3M)

1/2

3/4

3/4

3/4

 

1/2

1/2

1/2

30

(9.1M)

3/4

3/4

1

1

 

1/2

3/4

3/4

50 (15.2M)

3/4

 

1

1

1

 

3/4

3/4

1

80 (24.4M)

1

 

1

1 1/4

1 1/4

 

3/4

1

1

100

(30.5M)

1

1

1/4

1 1/4

1 1/4

 

3/4

1

1

150

(45.7M)

1

1

1/4

1 1/4

1 1/4

 

1

1

1 1/4

200 (61M)

1 1/4

1

1/4

1 1/4

1 1/2

 

1

1 1/4

1 1/4

 

 

 

 

 

 

 

 

 

 

 

14

Page 13 Page 15
Page 14
Image 14
A.O. Smith HW-120M, 225M, 200M, 160M GAS Connections, Correct GAS, Sizing GAS Supply Line, GAS Supply Pipe Sizes in Inches
Page 13 Page 15

HW-120M, 225M, 200M, 160M specifications

A.O. Smith is renowned for its range of advanced water heaters, and the 160M, 200M, 225M, and HW-120M models stand out as some of the most reliable and innovative options available. These water heaters are designed to deliver exceptional performance, energy efficiency, and user-friendly features, making them ideal for various residential and commercial applications.

The A.O. Smith 160M model boasts a robust design that ensures longevity and efficiency. It has a 160-gallon capacity, providing ample hot water for households with high demand. This model incorporates insulation technology that minimizes heat loss, contributing to energy savings and reduced utility bills. Additionally, it features a durable exterior that is resistant to rust and corrosion.

The 200M model takes performance a step further with a higher capacity of 200 gallons, making it suitable for larger homes or businesses. This model is equipped with advanced components, including a high-efficiency burner and a powerful thermocouple that ensures reliable heating. The 200M also includes user-friendly controls that allow for precise temperature settings and easy operation.

Next in line is the A.O. Smith 225M, which offers an impressive 225-gallon capacity. This model is designed for heavy-duty usage and features a reinforced tank to withstand high pressure. The 225M is also equipped with state-of-the-art flame retention technology that optimizes fuel use, enhancing the overall efficiency of the unit. This ensures that customers not only get hot water when needed but also experience considerable savings on energy costs.

Finally, the HW-120M model is a compact solution that does not compromise on performance. With a capacity of 120 gallons, it is ideal for smaller households or spaces where water heating needs are moderate. The HW-120M includes features such as an LED display for easy temperature monitoring and an integrated safety system that prevents overheating.

All these models utilize advanced technologies such as electronic ignition and enhanced insulation materials, contributing to a reduction in energy consumption and maintenance needs. The combination of these features makes A.O. Smith appliances a smart choice for consumers looking for efficiency, reliability, and performance. With a strong commitment to craftsmanship and innovation, A.O. Smith continues to set the standard in water heater technology, ensuring customers enjoy reliable hot water access while promoting energy efficiency.
Top Page Image Contents