Electronic And Circuit Diagram

Unlike gas water heaters that have gas burners to heat water, electric water heaters are based on a pair of metal heaters, one above and one below. These heating resistors are made of metal and are heated due to electrical resistance, similar to electric cookers. In a water heater the incoming cold water does not enter through the upper part of the tank, but rather near the bottom through an immersive conductor tube as seen in the diagram. Troubleshooting an Electric Water Heater. Changing the elements of an electric water heater

As a result of the supply of cold water near the bottom of the tank, the lower heating resistance is the fundamental part of the electric water heater. The upper heater resistor actually only acts when there is a high demand for hot water and only serves to heat water in the upper part of the tank. A constant supply of warm water during a shower is indicative of a poor upper heating resistance. A short supply of hot water during a shower is indicative of a defective lower heating element. Replacement heating resistors must be of the same style and rated voltage/wattage as those found in the water heater.

Troubleshooting an Electric Water Heater

Heating heaters of electric water heaters

Testing a heater resistance for an electric water heater

To test a heater resistance for an electric water heater, proceed as follows:

•     Use an electronic multimeter to test the heater resistors in an electric water heater.
•     Turn off the electric water heater from the main power panel. Do this by turning off the circuit breaker or fuse that powers the heater.
•     Wait for the heater to cool, this is important because the heating resistors work with a thermostat and the hot water in the tank will affect the electrical flow to the heating resistors.
•     Try cooling the "hot" water by turning on the hot water tap and letting it run until it cools.
•     Remove the panel that forms the access cover and the insulation that covers the terminal strip of the heating resistors. Bend the insulation outwards and in the opposite direction to the heating element.
•     Loosen the screws holding the wires of the two retaining screws and remove the cables.
•     Test the correct operation of the heating element by checking if there is any open or closed circuit (continuity) by using an electronic multimeter. Set the multimeter to "Ohms" and connect the red terminal to one of the terminals and the black terminal to the other terminal of the heater resistor.
•     If the reading in ohms is 0 on the digital multimeter or if the needle marks infinity (does not move) when using an analog marker, there is no flow of electricity through the resistor and it needs to be replaced.

If you get a resistance value in ohms when using the multimeter, then the problem is not the heating resistance itself. The problem may be in the other heating resistor or in the thermostat of the upper or lower heating units.

Removing the heating element

Screw and heating elements of flange type way:

•     Turn off the water heater from the main power panel. Do this by turning off the circuit breaker or fuse that powers the heater.
•     Next, empty the electric water heater with water.
•     Remove the panel that forms the access cover and the insulation that covers the terminal strip of the heating resistors. Bend the insulation outwards and in the opposite direction to the heating element.
•     Remove the thermostat cover if necessary. Be sure to disconnect the connection point of the thermostat.
•     Loosen the screws holding the wires of the two retaining screws and remove the cables.
•     Remove the screw type resistor by turning the resistor counterclockwise with a socket wrench to remove 1-1 / 2 inch resistors. Remove the existing gasket.
•     Remove the flange-type resistor by removing the four screws that hold the resistor in place. Remove the existing gasket.

 Change of heating elements

To replace the heating element, proceed as follows:

•     Clean the area around the gasket that holds the tank. It is a good practice to remove any sediment that is at the bottom of the tank if the heater resistance of the bottom is replaced.
•     Make sure that the spare resistor has the correct voltage and wattage rating. You can find this information on the flange or terminal block of the resistor or on the information plate of the water heater.
•     Fit the new heating resistor seal correctly and insert the assembly into the water heater tank. Adjust the screw type resistor by turning it clockwise with a resistor tube wrench until it is firm.
•     Close the drain valve of the water heater.
•     Open the nearest hot water faucet so that the tank fills completely with water.
•     Keep the hot water tap open for 3 minutes to obtain a constant flow of water. This will clean the pipes of all excess air and sediment.
•     Check for losses around resistance.
•     Connect the electrical wires to the electric heater resistor and make sure they are tight.
•     Replace the thermostat cover.
•     Replace the panel that forms the access cover.
•     Completely fill the water tank. This is of fundamental importance because if electricity is passed through heating resistors that are not immersed in water they will cause their destruction.
•     Turn on the water heater again from the main power panel. Do this by turning on the circuit breaker or fuse that powers the heater.