Temperature-Pressure Relief Valve
Explosion Hazard
•Properly sized
•Can result in overheating and excessive tank pressure.
•Can cause serious injury or death.
This heater is provided with a properly certified combination temperature - pressure relief valve by the manufacturer.
The valve is certified by a nationally recognized testing laboratory that maintains periodic inspection of production of listed equipment of materials as meeting the requirements for Relief Valves for Hot Water Supply Systems, ANSI Z21.22 • CSA 4.4, and the code requirements of ASME.
If replaced, the valve must meet the requirements of local codes, but not less than a combination temperature and pressure relief valve certified as indicated in the above paragraph.
The valve must be marked with a maximum set pressure not to exceed the marked hydrostatic working pressure of the water heater (150 psi = 1,035 kPa) and a discharge capacity not less than the water heater input rate as shown on the model rating plate. (For electric heaters, watts x 3.412 equals Btu/hr input rate)
For safe operation of the water heater, the relief valve must not be removed from its designated opening nor plugged.
The
Excessive length, over 30 feet (9.14 m), or use of more than four elbows can cause restriction and reduce the discharge capacity of the valve.
Water Damage Hazard
•
No valve or other obstruction is to be placed between the relief valve and the tank. Do not connect tubing directly to discharge drain unless a 6 inch air gap is provided. To prevent bodily injury, hazard to life, or property damage, the relief valve must be allowed to discharge water in quantities should circumstances demand. Ifthe discharge pipe is not connected to a drain or other suitable means, the water flow may cause property damage.
The Discharge Pipe:
•Shall not be smaller in size than the outlet pipe size of the valve, or have any reducing couplings or other restrictions.
•Shall not be plugged or blocked.
•Shall be of material listed for hot water distribution.
•Shall be installed so as to allow complete drainage of both the
•Shall terminate a maximum of six inches above a floor drain or external to the building. In cold climates, it is recommended that the discharge pipe be terminated at an adequate drain inside the building.
Shall not have any valve between the relief valve and tank.
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 riskfor scald injury.
Feel water before bathing or showering.
Temperature limiting valves are available.
Read instruction manual for safe temperature setting
The temperatureipressure relief valve must be manually operated at least once a year. Caution should be taken to ensure that
(1)no one is in front of or around the outlet of the temperature- pressure relief valve discharge line, and (2) the water manually discharged wilt not cause any bodily injury or property damage because the water may be extremely hot.
If after manually operating the valve, it fails to completely reset and continues to release water, immediately close the cold water inlet to the water heater, follow the draining instructions, and replace the
%errat re,,:Ta,ve
Discharge | Pipe |
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(Do Not Ptug or Cap) |
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Drain | Pan 2 1/2" |
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2DtP_t_ | elVIsaXi_'_e_l_al _ d | _ |
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the water | heater. _,,_ | U_ |
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| Drain I_,ne _/_ | _ | 6_'Maximum | |
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| ID Minimum |
| Drain | Air Gap |
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FIGURE 11.
12
