How to Test hot Water Heater Element With a Multimeter

How to Test hot Water Heater Element With a Multimeter? Electric water heaters use one or two heating elements to heat the water in the tank. When the water heater stops producing hot water, it may be due to the top element of the two-element water heater.

If your water heater is producing hot water, but it’s not hot enough, suspect the bottom element. If the water heater continues to trip the circuit breaker, the element is grounded and may cause an electrical short circuit. Use a multimeter to determine if an item is damaged and how it is damaged.

How to test hot water heater (step by step)

Turn off the circuit breaker on the main switchboard that powers the water heater. Most electric water heaters use a 30 amp bipolar circuit breaker.

Find the panel that is attached to the side of the water heater with screws. There are one or two panels, depending on the size of the water heater. Remove the screws from the panel and loosen them.

When removing the side panels, remove the exposed insulation. Depending on the age of the water heater, the insulation is composed of fiberglass or closed-cell extruded polystyrene foam. Wear protective goggles and gloves when removing fiberglass insulation.

Remove the plastic safety cover from the surface of the element. This cover is attached to the element and thermostat.

Place the non-contact voltage detector near the cables connected to the front of the element and each cable connected to the thermostat. If the water heater is still powered, the voltage detector will sound an audible alarm and its light will flash.

Loosen the two-part screw. Remove the wire from under the screw. Pay attention to the performance of the element printed on the side of the element side.

Turn the multimeter’s rotary knob to Rx1k (resistor multiplied by 1,000 ohms). With one of the multimeter probes, touch one of the screws on the front of the element. Place the remaining probe on the remaining screw. A 3,500-watt element should register 16 ohms, a 4,500-watt element should register 12-13 ohms, and a 5,500-watt element should register 10-11 ohms. If it is not registered with the multimeter, replace the element.

One of the probes touches one of the screws on the front of the element. Touch the metal part of the water heater with another probe. If the multimeter needle moves, the heating element is grounded and needs to be replaced. Be sure to test both screws on the front of the element.

Touch each screw with one of the multimeter probes. Place the remaining probe on the metal base attached to the element that enters the water heater. If the element is defective and the needle moves in front of the multimeter, it will need to be replaced.

Reconnect the wire to the front of the water heater element. Replace the plastic cover with the thermostat and element. Reinstall the insulation and join the panel to the side of the water tank. Switch on the water heater.

Things You Will Need

  • driver
  • Safety goggles
  • gloves
  • Non-contact voltage detector

Most household water heaters use natural gas (or sometimes propane) or electricity to heat the water. Some of the typical problems that occur are common to both types, while others are specific to electric water heaters.

Learn more about,  demand-type water heater, Test electric water heater Thermostat, common reasons for water problems

How the electric water heater works

Electric water heaters use 120 or 240 volts (240 volts is most common) to activate a metal heating element that protrudes from the sidewall into the water heater tank. Most water heaters have two heating elements. One is near the top of the tank and the other is near the bottom.

Electricity heats the metal ring of the element, which heats the surrounding water. Depending on the size of the water heater and the recovery time, the performance of these heating elements will vary from water heater to water heater.

What could go wrong?

Brand new water heaters work well for years, but common problems can occur over time.


Over time, layers of sediment from water can form in the lower half of the tank and eventually cover the lower heating element. This can significantly reduce the efficiency of the water heater as the deposits effectively cover the lower heating element and prevent that heat from being transferred to the water.

At this stage, it’s probably time to replace the water heater. Regular tank flushing can prevent sediment buildup, but it is too late to cover the lower heating element. At this point, there are several options other than replacing the water heater.

Heating elements can also burn

The most obvious symptom of this problem is when you suddenly notice that the hot water, usually coming out of the faucet, has just become hot. In this case, the upper heating element may be defective. The failed lower element shows slightly different symptoms.

The water coming out of the faucet gets hot enough at first, but soon it gets cold. Replacing the heating element is very easy for most home improvement enthusiasts. 


A thermostat is a device located in front of the heater that can regulate the temperature of the water supplied to the faucet. Electric water heaters can usually be placed under the access door on the side of the heater or mounted on the front. Curing the hot water problem is as easy as raising the temperature.

Also, check the thermostat reset button and the red button at the top of the thermostat. Simply resetting this floor may cause the heater to work again. Thermostat problems are very rare, but the heating elements are much more likely to burn and cause problems.

 DIY tips

As with any electrical project you plan to do yourself, be sure to turn off the circuit and follow all other electrical safety regulations before you start working on your water heater.

When replacing the heating element, make sure that the nominal voltage and power specified on the nameplate of the heating element match. For example, do not replace a 120-volt element with a 240-volt element. If you are not sure about the performance, take the old heating element to your nearest plumber and ask for a proper replacement.

If you need to replace the thermostat or heating element, draw a diagram showing how the wires are connected when removing the old one, or label each wire when cutting. Before removing the heating element, be sure to turn off the power and drain the water from the tank. For this purpose, there are usually drains at the bottom of the tank, below the bottom elements. 

Tip: Many experts simply replace both instead of determining which heating element is defective. This will prevent you from getting another alternative job shortly.

After replacing the heating element, refill the tank and open the tap to contract the air in the tank. When the tank is full again and the water drains out of the faucet at full power, close the faucet and turn on the water heater.

We hope you enjoyed this article How to Test hot Water Heater Element With a Multimeter. 



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