How to test water heater element?

Is your water heater supplying lukewarm or cold water?

While there may be various reasons for this sudden drop in temperature, a faulty heating element is most likely behind it. Sure, you can avail professional help, but sometimes you don’t have the time to wait that long.

The good news is there’s a DIY way for testing a water heater element, and we have curated this guide to help you with that.

So, let’s start!

What Causes A Water Heater Element To Malfunction?

Before taking you through the basics of testing a water heater element, it only makes sense to talk a bit about the causes of its failure in the first place.

Mineral Accumulation

If you have used a water heater, you’d know that the heating element has a limited service life. On top of that, high mineral content in the water can weaken it sooner rather than later. As the heating continues, the mineral deposition solidifies to reduce the heating capacity of the element.

Likewise, the lower elements can be wrapped with the mineral sediments, which eventually leads to a heating failure. A good preventative measure is to turn off the heater and flush it from time to time to clean the deposits.

Trapped Air Pockets

All water heaters elements should be operated while immersed in water. Otherwise, the heat generated by the element can burn through its copper.

However, trapped air pockets can prevent the upper element from coming in contact with the water, thereby causing a potential heater failure. Bleeding a line on the water heater once or twice a year can help extract any air pockets or sediment accumulation from the tank.

Malfunctioning Thermostat

The primary function of the thermostat is to control the heating elements by telling them when to heat the water at a certain temperature. When the temperature exceeds the maximum level, the high limit switch on the thermostat is triggered to shut down the power supply to the heater.

A malfunctioning thermostat won’t control the temperature of the heating element and may even cause it to burn.

Power Surge

A sudden increase in voltage resulting from a power surge or lightning can damage or burn the heating element. Each element has a specific voltage rating, exceeding which will invariably burn it.

Poor Wire Connection

Since the heating elements receive electricity from heavy gauge wires, they may stop working if a wire slips off the terminal due to poor connection. You may also face the problem of arcing. Hence, it’s best to keep an eye on the connections and fix them as and when required.

Tools Required

Here are a few essential tools that you must keep handy before testing a water heater element:

  • Screwdriver
  • Electrically insulated gloves
  • Safety goggles
  • Digital multimeter

How To Check Water Heater Element?

Step 1

The first critical step in testing a water heater element is to disconnect the appliance from the power source. For this, you need to locate the circuit breaker, which is usually placed in the central electrical panel (metal box attached to the wall).

During installation, most electricians mark the breaker with the name of the appliance that it powers to help you find it easily. But if you aren’t sure which breaker to disengage, just switch off the entire board.

Step 2

Next, locate the heating panel on the water heater. Depending on their size and capacity, most water heater models use one or two panels (attached to the side) protected by a metal cover. Upon removing this cover, unscrew the panels using the right-sized screwdriver. Make sure you don’t lose the screws.

Step 3

Based on the age of the water heater, it will have a layer of cellulose or fiberglass insulation below the metal cover. Remove it safely to get to the thermostat. Remember to put on the pair of gloves before doing so.

If the thermostat has a protective plastic cover, then pull out the tab to remove it. If not, then move on to the next step.

Step 4

For optimum safety, it’s best to double-check that the power has been switched off. Use a non-contact voltage detector and bring it close to the wire connecting the thermostat and the heating element. If it emits a beeping sound or light flash, then the electric supply is still on. In that case, recheck the main power switch.

Step 5

Depending on the size and model, your water heater will have one or two heating elements. While you may not be able to see them, you can identify the endpoints attached to a plastic plate with screws.

Step 6

At this point, set the digital multimeter dial to the lowest setting and note the reading of the heating element. Connect a probe on a screw attached to the element, but ensure that it doesn’t connect to any other part of the heater. Since the heating element has no terminals, you don’t have to worry about which one to test first.

Check the readings on the multimeter and match them to the resistance readings specified for that particular model. For instance, a 3,500 watt should read 16 ohms, a 4500 watt should read between 12 and 13 ohms, and a 5,500 watt should have between 10 and 11 ohms.

If the multimeter records a low or zero reading, it’s likely because of a faulty element that needs replacement. Do this for both the elements, if applicable.

Step 7

Put everything back together and switch on the power supply. If the element has been replaced, it may take a few minutes for the water to heat up.

Final Words

Testing a water heater element isn’t a herculean task per se, especially if you have all the necessary tools and take care of safety. But if you’re a first-timer or aren’t familiar with electrical appliances, then we would strongly recommend getting professional help. After all, it’s better to be safe than sorry!

Call Now