Read this brochure thoroughly before attempting to test your water heater, and be sure to follow these safety precautions.
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Ask for a low-cost inspection!
State law does not require the Department of Labor & Industries (L&I) to inspect residential water heaters. However, L&I will do a safety inspection of your water heater for $10. This low-cost service is available only to residential homeowners.
Keep Your Water Heater Safe
How to do a simple annual test
Locate the water shut-off valve for the coldwater inlet on the water heater. Know where the fuel (electric or gas) shut-off is located. Have the phone number for a plumber handy. Older temperature/pressure (T/P) relief valves that have not been tested for many years can become stuck in the open or closed position. If this happens, shut off the valve for the inlet to the water heater and call a plumber to repair. Try to test your tank during normal business hours. It's much easier to get help if you need it!
For more information:
Call the L&I Boiler/Pressure Vessel Section at 360-902-5271 or 360-902-4983
Look for signs of a worn or defective temperature/pressure (T/P) relief valve
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Before you hire a contractor or remodeler:
Verify the contractor's registration online at: www.Contractors.Lni.wa.gov by phone at 1-800-647-0982 or by contacting your local L&I office
A valve that doesn't open when the test lever is pulled without excessive force. Corrosion on the stem of the valve. Water leaking from the valve stem. Water leaking from the drain valve. A valve that does not close normally after being tested.
Protect yourself from hot water!
The discharge from a T/P relief valve can be very hot. It is very important that all T/P relief valves be installed properly with a discharge line piped down to minimize possible human contact, and above an adequate drain to avoid property damage. Please read and follow the instructions on the warning tag attached to your T/P relief valve. Other formats for persons with disabilities are available on request. Call 1-800-547-8367. TDD users, call 360-902-5797. L&I is an equal opportunity employer. PUBLICATION F620-048-000 [06-2009]
The potential for a serious accident exists when your water heater isn't routinely inspected.
Household hot water heaters are so common and trouble-free that we often take their safe operation for granted. Yet the potential for a serious accident does exist when water heaters are not routinely inspected.
Test the temperature/pressure (T/P) relief valve at least once a year.
Lifting the lever/test handle allows water to discharge and indicates that waterways are clear. To avoid scalding, a drain line should be attached to the T/P relief valve. Check to make sure that the capacity of the T/P relief valve is adequate and that the pressure setting is below the working pressure of the water heater tank. You can determine this by comparing the information on the T/P relief valve and water heater tank nameplates.
What do I do if there is a leak in my tank?
If your water tank appears to be leaking, stop using the tank and shut off heat input until the source of the leak is found. If the water heater tank itself is leaking, it probably is corroded through. REPLACE THE WATER HEATER. The owner's information pamphlet provided by the manufacturer is a valuable source of information about safe operation and installation.
What causes a hot water tank to explode?
Excessive temperature when combined with tank corrosion can cause a "pressureheat rupture" or explosion. If the water temperature is below 212 degrees Fahrenheit, the primary danger is scalding. However, if the water temperature is above 212 degrees, the water will turn into steam. Steam expands to 1,700 times the space it occupies as water. It can cause a violent explosion.
Is there any warning?
If steam without water comes from a hot water faucet, the situation is dangerous. Shut off electric power to an electric water heater or shut off the gas valve on a natural gas water heater, then call a qualified technician to replace the thermostatic control.
Testing the temperature/pressure (T/P) relief valve
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Read the WARNING information in this brochure. Clear the area around the overflow pipe and floor drain. Lift the test handle for approximately 5 seconds or until the water runs clear. Release the handle. If the T/P relief valve continues to run, lift the test handle up and down quickly to reseat the pressure relief valve. If the T/P relief valve continues to leak, you should have it replaced.
How can I minimize potential danger?
Make sure your water heater has a temperature/pressure (T/P) relief valve. The function of the T/P relief valve is to prevent dangerous temperature rise and overpressure of the water heater tank.
Testing a temperature/pressuef valve