Reliance Water Heaters N85390NE, N71120NE Installation Requirements, Gas pressure requirements

Installation Requirements

Gas pressure requirements

All models require a minimum gas supply pressure of 5.2” W.C. The minimum supply pressure is measured while gas is not flowing (static pressure) AND while gas is flowing (dynamic pressure). The supply pressure (static and dynamic) should never fall below 5.2” W.C. The supply pressure should be measured with all gas fired appliances connected to the common main firing at full capacity. If the supply pressure drops more than 1.5” W.C. as gas begins to flow to the water heater then the supply gas system including the gas line and/ or the gas regulator may be restricted or undersized. See Supply Gas Regulator section and Gas Piping section of this manual. The low gas pressure switch will shut down the water heater if the supply gas pressure drops below the minimum allowable value.

The gas valve on all models has a maximum gas supply pressure limit of 14" W.C. If a supply gas regulator is installed on the gas supply line, the maximum recommended pressure for the regulated gas supply is 11" W.C. The maximum supply pressure is measured while gas is not flowing (static pressure) AND while gas is flowing (dynamic pressure).

Supply Gas Regulator

The water heater covered by this manual may require the installation of a supply gas regulator. If the supply gas pressure exceeds 14 inches W.C. a supply gas regulator must be used. If the gas supply pressure exceeds 14" W.C. in a multiple water heater installation, each water heater must have its own supply gas regulator. If required, the supply gas regulator shall be rated at or above the Btu/hr input rating of the water heater it supplies. If a supply gas regulator is installed on the gas supply line, the maximum recommended pressure for the regulated gas supply is 11" W.C.

Supply gas regulators shall have inlet and outlet connections not less than the minimum supply gas line size for the water heater they serve as shown in Table 9. The Maxitrol 325-7L or equivalent is recommended.

Power Supply

The water heaters covered in this manual require a 120 VAC, 1Ø (single phase), 60Hz, 15 amp power supply and must also be electrically grounded in accordance with local codes or, in the absence of local codes, with the National Electrical Code, ANSI/NFPA 70 or the Canadian Electrical Code, CSA C22.1.

WATER TEMPERATURE CONTROL AND Mixing Valves

Water temperature over 125°F (52°C) can cause severe burns instantly resulting in severe injury or death.

Children, the elderly and the physically or mentally disabled are at highest risk for scald injury.

Feel water before bathing or showering.

Temperature limiting devices such as mixing valves must be installed when required by codes and to ensure safe temperatures at fixtures.

Water heated to a temperature which will satisfy clothes washing, dish washing, and other sanitizing needs can scald and cause permanent injury upon contact. Short repeated heating cycles caused by small hot water uses can cause temperatures at the point of use to exceed the water heater’s temperature setting by up to 20°F (11°C).

Some people are more likely to be permanently injured by hot water than others. These include the elderly, children, the infirm and the physically/mentally disabled. Table 6 shows the approximate time-to-burn relationship for normal adult skin. If anyone using hot water provided by the water heater being installed fits into one of these groups or if there is a local code or state law requiring a certain water temperature at the point of use, then special precautions must be taken.

In addition to using the lowest possible temperature setting that satisfies the demand of the application a Mixing Valve should be installed at the water heater (see Figure 10) or at the hot water taps to further reduce system water temperature.

Mixing valves are available at plumbing supply stores. Consult a Qualified Installer or Service Agency. Follow mixing valve manufacturer’s instructions for installation of the valves.

Table 6.

Water Temperature	Time to Produce 2nd & 3rd
	Degree Burns on Adult Skin

180°F (82°C)	Nearly instantaneous
170°F (77°C)	Nearly instantaneous
160°F (71°C)	About 1/2 second
150°F (66°C)	About 1-1/2 seconds
140°F (60°C)	Less than 5 seconds
130°F (54°C)	About 30 seconds
120°F (49°C)	More than 5 minutes

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