A.O. Smith Water Heater Temperature and Pressure Relief Valve Explosion Harzard

Temperature and Pressure Relief Valve

Explosion Harzard

Temperature-pressure relief valve must comply with ANSI Z21.22-CSA 4.4 and ASME code.

•Properly sized temperature- pressure relief valve must be installed in opening provided.

•Can result in overheating

and excessive tank pressure.

•Can cause serious injury or death.

(T&P)

RELIEF VALVE (OPTIONAL TOP T&P RELIEF VALVE NOT SHOWN)

DISCHARGE PIPE

(DO NOT CAP OR PLUG)

DRAIN LINE 3/4" ID

\\MINIMUM

1" MINIMUM	.-=,,-	-,._--_	V
METAL	I	_.LI _,l_	_- --	6" MAXIMUM
DRAIN PAN-_,,_			_'_	AIRGAP

DRAIN ._

FIGURE 15A.

For protection against excessive pressures and temperatures, a temperature and pressure relief valve must be installed in the opening marked "T & P RELIEF VALVE" (see Figure 15A). This valve must be design certified by

a nationally recognized testing laboratory that maintains periodic inspection of the production of listed equipment or materials as meeting the requirements for Relief Valves for Hot Water Supply Systems, ANSI Z21.22. The function of the temperature and pressure relief valve is to discharge water in large quantities in the event of excessive temperature or pressure developing in the water heater. The valve's relief pressure must not exceed the working pressure of the water heater as stated on the rating plate.

IMPORTANT: Only a new temperature and pressure relief valve should be used with your water heater. Do not use an old or existing valve as it may be damaged or not adequate for the working pressure of the new water heater. Do not place any valve between the relief valve and the tank.

The Temperature & Pressure Relief Valve:

•Must not be in contact with any electrical part.

•Must be connected to an adequate discharge line.

•Must not be rated higher than the working pressure shown on the rating plate of the water heater.

The Discharge Line:

•Must not be smaller than the pipe size of the relief

valve or have any reducing coupling installed in the discharge line.

•Must not be capped, blocked, plugged or contain any valve between the relief valve and the end of the dis-

charge line.

•Must terminate a maximum of six inches above a floor drain or external to the building.

•Must be capable of withstanding 250°F (121°C) without distortion.

•Must be installed to allow complete drainage of both the valve and discharge line.

T&P Relief Valve and Pipe Insulation (Some Models)

1.Locate the T&P Relief Valve on the water heater.

2.Locate the slit running the length of the insulation.

3Spread this slit open and slip it up under the T&P Relief Valve. See Figure 15B. Apply gentle pressure to the insulation to ensure it is fully seated on the T&P Relief Valve. Once sealed secure the insulation with a section of tape.

IMPORTANT: The insulation or tape should not block or cover the T&P Relief Valve drain opening. Also the

insulation or tape should not block or hinder access to the T&P Relief Valve manual relief lever.

4.Next locate the hot water (outlet) & cold water (inlet) pipes to the water heater.

5.Select one of the sections of pipe insulation and locate the slit that runs the length of the insulation.

6.Spread the slit open at the base of the insulation and slip it over the cold water (inlet) pipe. Apply gentle pressure along the length of the insulation to ensure it is fully seated around the cold water pipe. Also ensure that the base of insulation is flush with the water heater. Once seated, secure the insulation with a section of tape.

7.Repeat steps 5 through 6 for the hot water (outlet) pipe.

T&P RELIEF VALVE INSULATION

F LEVER

RELIEF VALVE

© DRAIN LINE

FIGURE 15B.

Combination Space Heating/Potable

Water System

Some water heater models are equipped with inlet/outlet connections for use with space heating applications. If this water heater is to be used to supply both space heating and domestic potable (drinking) water, the instructions listed below must be followed.

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