A.O. Smith FMV-50, FMV-40, FMV-30 Water Piping Pressure Test, Temperature-Pressure Relief Valve

The water within the water heater tank expands as it is heated and increases the pressure of the water system. If the relieving point of the water heater’s temperature-pressure relief valve is reached, the valve will relieve the excess pressure. The temperature-pressure relief valve is not intended for the constant relief of thermal expansion. This is an unacceptable condition and must be corrected.

It is recommended that any devices installed which could create a closed system have a by-pass and/or the system have an expansion tank to relieve the pressure built by thermal expansion in the water system. Expansion tanks are available for ordering through a local plumbing contractor. Contact the local water supplier and/or a service agency for assistance in controlling these situations.

NOTE: To protect against untimely corrosion of hot and cold water fittings, it is strongly recommended that di-electric unions or couplings be installed on this water heater when connected to copper pipe.

FIGURE 5.

Figure 5 shows the typical attachment of the water piping to the water heater. The water heater is equipped with 3/4 inch NPT water connections.

Note: If using copper tubing, solder tubing to an adapter before attaching the adapter to the cold water inlet connection. Do not solder the cold water supply line directly to the cold water inlet. It will harm the dip tube and damage the tank.

WATER PIPING PRESSURE TEST

This section is only for the manufacturer installing the water heater when the installation is to comply with H.U.D. Standards.

When testing the water ways, H.U.D. Standards state:

“Water distribution system. All water piping in the water distribution system shall be subjected to a pressure test. The test shall be made by subjecting the system to air or water at 100 psi for 15 minutes without loss of pressure. When air pressure is used, the water heater shall not be connected during the test”.

NOTE: If water piping system is to be air pressure tested, the water heater must be disconnected from the water piping system. Failure to disconnect the water heater during air pressure testing of water piping system could result IN DEATH, SERIOUS BODILY INJURY,

OR PROPERTY DAMAGE.

FIGURE 6.

Temperature-Pressure Relief Valve

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