About the Post

Jerry Hardy

Author Information

I was a Building Contractor along with owning rental properties where I did most of the repairs myself. Its my pleasure to pass on to you some of the methods I had used in the past. Hopefully, this will save you the expense of hiring a professional to do the work.

Electric Water Heater Not Heating



When an electric water heater fails to heat to its usual temperature, the causes are, in most cases, one of three conditions. Either the heating element, temperature thermostat, or dip tube is not functioning properly.  Each of these components will be discussed in this article providing all the procedures necessary for electric water heater troubleshooting.

 

TESTING HEATER ELEMENT

1. Turn off the power to the water heater at the main electrical panel.

2. Remove the two metal panels on the upper and lower side of the tank.

3. Carefully remove the insulation over the heating elements and the plastic safety guards.

4. Remove the safety guards.

5. Test both the upper and lower heating elements for continuity with an Ohmmeter or multimeter by connecting a test lead from the meter to each of the element terminals. If the ohmmeter needle doesn’t move or no reading is given, that indicates that the element is defective and must be replaced. A good element will have an ohm reading between 10 and 16.

 HOW TO REPLACE WATER HEATER ELEMENT

water heater element

Turn off water

1. Turn off the water at the valve on the supply line to the tank.

Turn off power at the breaker box

Drain tank

1. Attach a garden hose to the drain valve located at the bottom of the water heater tank

2 Open the pressure overflow valve at the top of the tank.

3. Open the drain valve at the hose and begin draining the tank. If the upper element needs replacing it is only necessary to drain the tank just below the element. After allowing the tank to drain approximately 10 minutes, using an 1 ½ inch socket tool, loosed the element only slightly. If water begins to leak out, re-tighten the element and allow the tank to drain for another few minutes and try again. If no water is leaking from the slightly loosened element, slowly loosen it further to be assured the water level is below the element. If the lower element needs replacing, it will be necessary to remove most all the water from the tank. Since this is the case, I would suggest draining all the water.

Remove the element

Remove the two wires fastened to the water heater element. Using the 1 ½ inch socket, completely remove the element.

Install new element

1. Prior to installing the new element, make sure it has a rubber seal below the hex portion of the element. Insert element and tighten with the 1 ½ inch socket. 2. Reattach the two wires. It doesn’t matter which wire goes to which screw.

Remove garden hose

1. Remove the drain hose after tightening the drain valve securely.

Refill the water tankwater heater

1. Close the pressure relief valve

2. Open a hot water tap nearest the water heater

3. Open the inlet water valve and allow the tank to fill completely. When water begins to run out of the opened  tap, the tank is full.

4. Turn off the tap.

Check for leaks

Inspect the replaced element for leaks

Replace the panels

1. Replace the plastic protective cover over the thermostat and element

2. Replace the insulation.

3. Install the panels

Turn on the power

 

 TESTING HEATER THERMOSTATS

 

Turn off power

Remove both upper and lower access covers, insulation and plastic safety covers

Check reset button

Check to make sure the reset button was not tripped by pushing in the red button on the upper thermostat.

TESTING UPPER THERMOSTAT

thermostat

upper thermostat

 

Set temperatures

Use a screwdriver to set the upper (top) thermostat temperature to the highest setting. Set the lower thermostat temperature to the lowest setting.

Turn the water heater power on.

 Check voltage at thermostat

The voltage should be checked by placing test probes on the two wires above the reset button to make certain that voltage is coming into the heater. The voltage should be 240 volts. Now test the heater thermostat by placing the test probes on the upper element screws. The heater thermostat is defective if there is no power to the element. If there is power at the element, it is time to check the lower thermostat.

 

thermostat

lower thermostat

 

TESTING LOWER THERMOSTAT

 

Re-set temperatures

Set the thermostat temperatures by setting the upper thermostat to its lowest setting and the lower thermostat to its highest setting. The upper thermostat will make a click to off as you set the temperature. If you don’t hear a click, give the water time to heat up.

Check for voltage

Now check for voltage at the lower element If there is voltage at the element, give the water time to heat up. Listen for a click on the thermostat as you lower the temperature setting. The thermostat is working properly if you hear the click. Continue further if you don’t have voltage at the element leads.

Next, place one test probe on the top screw of the lower thermostat and the other probe on the water tank.  You should have 120 volts at this position. If the upper thermostat is not sending current to the lower thermostat, you will not get a reading on the meter, meaning the upper thermostat needs replacing.

If you have power, follow the next step.

Hold one test probe on the water tank and the other probe on the lower screw of the thermostat. If the reading is not 120 volts, replace the thermostat.

 

HOW TO REPLACE  HEATER THERMOSTAT

The first thing you should do is make a sketch of the location of the wires attached to the thermostat and then remove all wires. Now pull back on the two metal clips which are holding the thermostat and slide out the unit. Insert the new thermostat between the two metal clips making certain that it is held tight against the tank so it will be able read the temperature of the tank. Set the temperature between 120 and 140 degrees. Reconnect the wires, tightening the holding screws firmly against the wire. If the upper thermostat is replaced, make sure the red reset button is pushed in. Attach the plastic protective cover over the thermostat followed by inserting the removed insulation. Replace the metal cover plate. Before turning on the power, make sure the tank has been filled.

 

REPLACING THE DIP TUBE

If the water from the heater is not as warm as it usually is, it could be that the dip tube is defective. Since the dip tube is commonly made in plastic, it will deteriorate over time.  The dip tube is designed to bring cold water into the bottom of the tank since hot water naturally rises to the top of the tank. A broken heater dip tube will bring cold water to the upper tank where it leaves on its way to the sink or shower before being heated.

Turn off power

Turn off the power to the heater at the breaker. It is a good practice to stick a note on the breaker box to warn others that you are working on the heater.

Turn off waterdip tube

Close the valve on the water supply line to the heater.

Open a hot water tap

This is done to release water pressure in the tank preventing overflow when removing the dip tube.

Disconnect the water supply line

After disconnecting, push the supply line off to one side to give working room.

Remove  the nipple

Remove the short threaded pipe or nipple that was attached to the supply line at the top of tank.

Remove the dip tube

Using a screwdriver or pliers, pry up on the dip tube until it is high enough to grip by hand. Pull tube up and out of the tank.

Insert new tube

Prior to inserting tube, wrap the upper end with approx. 5 wraps of plumbers tape.

Replace nipple

Attach the nipple above the dip tube to the top of the tank.

Re-attach water supply line

Close hot water tap

Turn on water

Turn on power


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Electric Water Heater Not Heating

One Response to “Electric Water Heater Not Heating”

  1.  

    hi It's a good post.

    December 23, 2012 at 7:50 pm

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