Three months ago, we installed a new 50-gallon Whirlpool electric water heater. We have found that it runs out of hot water after one ten-minute shower. This happens even when we don't use the washing machine or dishwasher on the same day. My husband says that when he shaves, the water coming out of the faucet isn't hot enough to make him move his hand out from under the water flow. Does this mean there's something wrong with the water heater?

Yes and no. Even though this is a new appliance, it's possible that a lower heating element is defective or the upper thermostat is not working properly to allow the bottom element to work. It's also possible that the dip tube, which allows cold water to enter near the bottom of the tank, is missing. If that's the case, then cold water could mix at the top of the tank and discharge through the hot water outlet without being heated. Because the tank was just installed, it is under warranty from the manufacturer so go back to the company that installed it.

However, my instincts tell me that the thermostats are at their factory settings of 120 degrees. In general, this temperature setting saves energy and is considered hot enough for most home uses. It also helps protect users from scalding, particularly children, the disabled, and the elderly. At 120 degrees at the fixture, it takes a little more than 5 minutes to produce serious burns; at 130 degrees, it takes about 30 seconds; and at 140 degrees, it takes less than 5 seconds.

I think 120 degrees seems low for a family of four, so I recommend setting the temperature between 130 and 140 degrees. This will make the water hot enough so you are forced to mix it with cold water to achieve a comfortable temperature. Mixing it with cold water will also help make the hot water last longer.

In new homes and in homes where tub/shower plumbing is being changed, an anti-scald pressure-balanced shower valve (faucet) will be required. Designed to compensate for changes in water pressure, this valve makes sure the water temperature doesn't change during a shower. For additional scald protection, most pressure-balanced valves have a stop that prevents the handle from rotating beyond a set position, limiting the amount of hot water the valve can deliver. This valve can be adjusted.

In older homes a tempering or thermostatic-controlled valve can be installed on the hot water outlet just after it leaves the water heater. This mechanism allows you to increase the water heater temperature, but it controls the hot water temperature at the fixture by mixing cold water with the hot water to regulate the temperature. Again, this valve is adjustable.

To check your water temperature, run the hot water at the kitchen faucet until it is fully hot and hold a candy or meat thermometer in the running water.

To check the thermostat settings, first turn off the power to the tank and remove the screws that hold the upper and lower thermostat covers. Once the covers are removed, use a flat-head screwdriver to reset the thermostat to the desired temperature, reinstall the cover, and turn on the power. You can recheck the water temperature using the thermometer once the water has heated up in about three hours.

On a friendly note, if your jurisdiction follows the national plumbing code or mechanical code, a plumbing permit will be required to replace an electric water heater and a mechanical permit to install a gas-fired water heater.

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C.R.S., Inc. · Spokane, Washington · USA