Q&A for How to Repair an Electric Water Heater

You might have a faulty thermostat. This could cause the water to heat past the desired temperature. This can be extremely dangerous, especially if other safety features are disabled or damaged.

It could be drawing too much power from the circuit or there could be a fault in the wiring or water heater. To diagnose the problem, talk to an electrician.

You may have a dishwasher that heats water for itself; it could have a point-of-use water heater connected to it, or it could be connected to its own water heater. If your main water heater is broken, but one of the above conditions exist, the dishwasher will have hot water despite the broken main water heater.

It could be many things. You could have an undersized heating element(s), failed element, a 240V heater wired to 120V service, etc.

Reverse the tank orientation so that water pipes do not travel over or near the electrical wiring.

TPR valves are tricky--they are often faulty out of the box. Replace the TPR valve again. If the problem doesn't stop, call a plumber.

If the controls and elements are good, I suspect a power or wiring issue. Double check the voltage on the circuit in the home's electrical panel and at the point it connects to the heater - most are 240 volts.

Your safety valve has given in. To be safe, replace the thermostat, element, and safety valve. For extra peace of mind, replace vacuum breakers as well. Clean the vessel also.

You have a faulty thermostat. Once the thermostat has satisfied - reached the temperature you have set - it should open to interrupt the power from reaching the heating element. The heating element continues to heat the water until the "high temperature limit switch" senses this super-hot water and opens. The power remains off until it is manually reset - by a person. If this happens twice, you need to find/replace the faulty thermostat.

This sounds like a bad thermostat. If you have a gas type heater, you may have a bad thermocouple. The valve may also be stuck in "pilot" or fail to open fully to a "high fire" level.

There is a leak somewhere. Check and correct any leaks in the cold water inlet pipes or the hot water outlet pipes threaded and soldered connections. Shut off the power to the heater and open the access panels. Look for evidence of water leaking (rust) from the openings in the tank for the elements to enter. Tighten element or element bolts (depending on style element your tank has). You may need to drain the tank to replace elements and gaskets. If everything looks dry around the elements and there is no leak from pipes supply cold water to the tank or hot water from the tank, your tank has most likely developed a leak and will require replacement. Check to see if your tank is under warranty before buying a new one.

I suspect a faulty heating element or leaking voltage to ground. Steps 1 through 25 under Part 1 go into great detail and step-by-step instructions on how to test elements. Be sure to do this with power off!

It may be the bottom thermostat. If followed properly, the procedure in this wiki should have allowed you to identify the problem component.

The circuit breaker opens the electrical circuit to prevent excess current flow. The reset button on the water heater tank opens the electrical circuit to prevent the water from being heated above temperatures (approaching boiling) that could cause the tank to burst. In other words, they both interrupt current flow, but because of the presence of two very different problems.

Water leaks that are at soldered pipe joints can usually be repaired fairly quickly and inexpensively. if you lack the skills or tools to do this work, a qualified or licensed plumber will be required. Leaks due to corrosion at threaded connections on and into the tank may be resolved by tightening or removing and applying a wrap or two of PTFE (aka "Teflon") tape on the male threads. Leaks between heating element and the tank my be fixed by removing and replacing the gasket (after cleaning the tank opening in the heater). Leaks on the tank that are not at gasketed, threaded or soldered will be very difficult--if not impossible--to repair.

The dip or fill tube is probably broken. It is the tube that brings in the cold water and distributes it to the bottom of tank.

The water heater's sacrificial anode is usually accessible from the top of the water heater (make sure you shut off power and the cold water supply, then open a hot water faucet to relieve the pressure in the tank first). Look for a hex head (bolt) fitting on the top of the tank; this is the top of the anode itself. Twisting it with an open-end or socket wrench will allow you to remove it and insert a replacement.

Allow the apartment maintenance crew to handle this, as you do not want to be accused or damaging the tank part(s) or private property. However, if it is causing an emergency problem, call a plumber or the fire brigade to help prevent a harmful situation from developing.

You can replace the upper element after draining the tank below the level of the element. Measure the distance from the top of the heater to the element and the overall all length of the heater. The element distance is 25% of the overall length of the heater, drain at least 25% of the water from the tank. 25% of 40 gallons = 10 gallons. After replacing the element and snugging securely to the tank, refill the tank with water. Do not power the tank until you have water flowing out of a hot water faucet (no air sputtering). A heating element that is not fully immersed in water will burn out *instantly* when power is applied!

The thermostat is either faulty - or is making poor contact with the tank (rust build up on the tank or insufficient spring pressure to keep it pressed to the tank). To fix this, try: 1) cleaning the rust off the tank; 2) adjusting for better spring tension; or 3) replacing the thermostat.

The water heater has a sacrificial anode tube or rod that can be replaced to help with the longevity of the tank.