No Hot Water From an Electric Water Heater

Before you open anything

• Is it every tap? If one shower or sink runs cold and the others are hot, the heater is fine. See no hot water in one faucet or shower.
• Did someone just use a lot? Electric tanks recover slowly. A.O. Smith puts recovery at 60 to 90 minutes for electric tanks, compared with 30 to 40 for gas. Give it an hour.
• Is there a leak? Water around an electric heater changes the job. Go to water heater leaking first.

Likely causes, in the order to check

1. 1

   Cause 1: Tripped breaker

   Find the water heater breaker in your panel. It's a double-pole breaker, two handles tied together. If it's off or stuck in the middle, push it fully off, then on. A.O. Smith's fix is to reset the breaker and check for shorts, loose wires and grounded elements.

   If it trips again right away or when the heater starts heating, stop resetting it. Our page on a water heater breaker that keeps tripping covers the causes.

2. 2

   Cause 2: Tripped reset button (ECO)

   The ECO (energy cut off) is a high-limit switch that cuts power to the elements when the tank overheats. It sits behind the upper access panel that covers the upper thermostat. With the breaker off, remove the panel, fold back the insulation, and press the red button firmly until it clicks. Close it up and restore power.

   A trip means the water got too hot, and the A.O. Smith handbook says a tripped ECO points to a problem with one of the elements. A.O. Smith also warns that repeated tripping indicates serious problems like shorted elements or faulty thermostats. If the button trips again within days, the reset is not the repair. See the reset button guide.

3. 3

   Cause 3: A burned-out element

   Most residential electric tanks have two elements, upper and lower, each controlled by its own thermostat. A.O. Smith lists faulty heating elements as a cause of no heat. The pattern helps:

   • No hot water at all: often the upper element or upper thermostat, because the upper thermostat decides when power goes to the lower element.
   • Some hot water that runs out fast: usually the lower element.

   Test elements with a multimeter, power off and wires disconnected. No reading across the two screws means the element is open (burned out). Any reading between a screw and the tank means it's grounded. The steps are in how to test a water heater element.

4. 4

   Cause 4: A failed thermostat

   If both elements test good and the breaker holds, the thermostat may not be sending power. A.O. Smith says faulty thermostats can trip the high-limit switch, and a thermostat that won't close leaves the water cold. Checking for voltage at the thermostat terminals is live-circuit work. If you aren't trained for it, let a pro do it.

5. 5

   Cause 5: Thermostat set too low

   Someone bumps the dial, or a vacation setting never got reset. A.O. Smith's factory setting is about 120°F, and the guide recommends keeping it there. Both thermostats should be set the same.

Electric water heater not getting hot enough

Warm but not hot usually points to a failed lower element, a thermostat set low, or heavy demand the tank can't keep up with. Sediment in the bottom of the tank can bury the lower element and slow heating too. A.O. Smith recommends draining a few gallons from the tank once a year to clear sediment. A broken dip tube, which mixes incoming cold water into the top of the tank, gives the same symptom. If you suspect the tank is just too small, see water heater runs out of hot water and water heater not hot enough.

New electric water heater, no hot water

On a brand-new install, check the basics first: the breaker is on, the wiring is connected at the junction box, and the reset button hasn't tripped in shipping. The bigger worry is a dry fire. If power reaches the elements before the tank is full, they can burn out. The A.O. Smith handbook describes the dry-fire condition as power on with the tank not full. If the new heater was switched on before every hot tap ran without air, test the elements.

When to call a pro, and what it costs

Call a plumber or electrician if the breaker or reset trips again, if you see scorched wires, or if you'd rather not open the covers. HomeGuide's figures:

Expect a service call fee of $50 to $200 in many areas. On an old, rusty tank, compare the quote with water heater installation cost before you approve it.