How to Repair an Electric Water Heater

2024 Author: Samantha Chapman | [email protected]. Last modified: 2023-12-17 09:13

No more hot water comes out? You can easily repair (and if necessary replace) the control and heating elements of the most common 120, 208 and 240 volt domestic water heaters, i.e. traditional water heaters with line voltage control, and not the microprocessor based ones that are starting to spread in stores. You can click on each photo to enlarge it and see the details.

Steps

Part 1 of 3: Repairing the Water Heater

Step 1. Check the electrical panel to make sure that the switch is on (and not turned off or simply tripped), that the fuses (if used) are properly installed and not blown

Turn the switch back on and replace any skipped ones. At this point, wait 30-60 minutes to give the water time to heat up. If the water remains cold, then continue with the next steps.

Step 2. Disconnect the power supply

Many water heaters are powered by voltages that can cause electric shocks, burns or even death if they come into contact with conductive elements. Disconnect the power supply from the electrical panel by removing the fuses or turning off the switch on the water heater. Completely remove and keep the fuses or close the panel tightly and attach a label to the outer cover, so that it is clearly visible to anyone that there is work in progress on the water heater. This will prevent anyone from turning it on while you are working on it.

Step 3. Remove the top panel (and, if present, the bottom panel as well)

These metal panels are generally held in place by screws. Remove the screws and save them for when you need to reassemble everything. Use a voltmeter or test bulb to check between the connection terminals and the tank (which should be grounded), and make sure there is no power. If there is still power, stop until you are sure you have found the switch or fuses. Close the switch or remove the fuses to prevent someone from turning on the water heater while you are working on it.

Step 4. Remove any insulation that obstructs access or view of the controls (thermostat and high temperature switch) and of the heating element

Once the thermal insulation has been removed, protective plastic elements will be visible. Carefully move the cables away from these protective elements, lift the tab at the top of the clip, and remove the protective plastic elements so that you can access the terminals.

• View after removing the protective plastic elements:

  

Step 5. Look for obvious signs of damage

Water heaters can leak, if the tank is damaged, or even if the cold or hot water pipes are badly fitted or welded, or if the heating element and tank opening are not properly installed. sealed.

• Rusty cables or controls - both internally and externally

  

• Rust is conductive, even that formed on the insulation of electrical cables. This could cause fatal electric shocks, heat and melt the insulation or even cause burns. Carbon black deposits are indicative of a short circuit. There may be a bare copper wire that is difficult to spot due to these short-circuiting carbon deposits.
• As a result of damage, the circumference of the electric cables in some places may be reduced. In this case, it is likely that they do not have the thickness necessary to conduct the required electricity. These points of damage also become a source of heat. It is extremely important to repair or replace all parts that are damaged due to water infiltration or short circuits. These parts include electrical cables, their insulations, jumpers, and the controls themselves. As mentioned before, rust is a conductor and can allow electrical current to travel through unwanted paths. These paths can be dangerous, making the fault difficult to detect.

• In this figure, the yellow cable between the control and the element appears to be short-circuited to the tank (or to another metal) due to the presence of a sooty black deposit on the cable and at the top. Look at the bottom left terminal of the thermostat - excessive heat has begun to melt the plastic around the terminal.

  

Step 6. Identify the following items:

• The high temperature switch:

  It is equipped with a reset button and has 4 terminals, including screws and cables, connected. Generally, the first two terminals are connected to two electrical cables, which in turn are connected to the wiring compartment that supplies power to the rest of the water heater controls and the heating elements. The "Upper Controls" consist of the High Temperature Switch and the Upper Thermostat. The "Lower Controls" are represented by the Lower Thermostat only (in most electric water heaters there is no high temperature switch for the lower section). Three of the four terminals are numbered and are visible in the photo (# 1, # 3,  terminal # 2 is not identified as it is connected to the bottom thermostat via a jumper installed directly by the manufacturer).

  

• The Thermostat:

  it is equipped with a graduated and adjustable knob. The knob can show the letters "A", "B", "C", qualitative indications such as "warm, hot and very hot", or, as in the example in the photo, it can show the temperature expressed in Celsius degrees. The thermostat is located just below the high temperature switch.

  

• The heating element:

  has two terminals, each of which is connected to an electrical cable. One of these two cables is generally connected to the associated thermostat (in these photos the thermostat is just above the terminals of the heating element). It is generally positioned under the controls and holds the controls by means of a clip of some kind (in the photo, the heating element has two terminals and a gray metal clip attached to the control support).

  

Step 7. Test to make sure there is no power

Set the voltmeter (or multimeter) for measuring alternating voltage (AC) and insert the black probe in the black or common terminal, while the red probe in the red terminal or with the indication of the Volts.

Step 8. Measure the voltage

Set the highest voltage range. Place the black probe on the terminal of the high temperature switch, as shown in the image on the right. If you want, you can lower the range of values, provided that the selected range is greater than the voltage measured in the higher range. If you can't make sure that the power is off, then do a further check on the circuit board. Do not proceed until you are certain that there is no power; otherwise you could burn the voltmeter and, moreover, in the following steps, there is a risk of electric shock or burns.

In the photo above, the voltmeter reads 0.078 volts. This value, less than a tenth of a volt, is to be interpreted as a power failure

Step 9. Set the Meter to read Ohms or Resistance

Watch the multimeter reading. If it is analog, the needle or pointer will be at rest for the highest resistance values (the leftmost position), and this is an indication of an open circuit. In the case of a digital multimeter, you can have readings of the type "OL" or "1" ("1" without leading and trailing zeros), which represent the highest value the multimeter can detect (in the same way as a calculator) in conditions of overload or value tending to infinity. An infinite resistance value is referred to as an “Open Loop” (OL). Take note of this open circuit indication detected with this instrument (when you select a range of currents or voltages and get a reading "OL" or "1", you should repeat the measurement by increasing the range). If you are not sure of the indication that your instrument should provide in an "OL" type condition, then leave the terminals disconnected and do not touch anything; then turn on your multimeter or volt-meter and, at this point, you should have the reading of the air resistance between its terminals, which, under normal conditions, should be infinite.

Step 10. Remove one of the heating element wires (it doesn't matter which one)

Step 11. Connect the black probe to the common terminal

Step 12. Connect the red probe to the terminal with the indication "Ohm" or "Resistance", in case there are more terminals to choose from

Step 13. Set (if present) the interval R x 1

If the voltmeter or multimeter you are using does not have range adjustment, then it probably has self-adjustment. This simply means that your instrument will automatically adjust to the appropriate intervals. This feature is usually more common in digital instruments than analog ones. Many analog instruments without range adjustment often only support one range; these instruments offer greater accuracy for reading low values (0 to 500K, or 1M Ohm) rather than high values (greater than 1M Ohm), but will be fine for this procedure. Pay particular attention, during the readings, to the display of an instrument equipped with self-adjusting range: there is a huge difference between 20, 20K or 20M Ohm. "K" indicates a multiplier for one thousand, while "M" for one million. In the example above you could read 20 ohms, 20,000 ohms (20K or 20 kilo ohms) and 20,000,000 ohms (20 M or 20 mega ohms); each of these values is a thousand times larger than the previous one.

Step 14. Connect the metal probe tips together

The analog multimeter should move towards the lower resistance values (or all the way to the right). A digital multimeter should read “0” or a very low number close to zero. Find the zero adjustment knob and turn it so that you have a reading of zero (or as close as possible); many tools may not have this functionality. Once reset, this position of the indicator will represent a "Short Circuit" or "Zero Ohm" for the selected range of values. The instrument needs to be reset every time the resistance range changes. Resistance values detected will not be accurate if the meter is not zeroed correctly.

In the example image, the instrument indicates a resistance value of 0.2 ohm (or zero). The instrument may not be able to read lower values and, since the reset function is not present, this value is to be considered as “0 ohm”

Step 15. If necessary, replace the batteries

If you are unable to obtain the indication of zero ohm, it is possible that the batteries of your instrument are flat and must therefore be replaced. Repeat the previous step using fresh batteries. Normally, digital instruments also show the state of charge of the batteries or an indication in case they are exhausted. Manually check the meter to determine the state of charge of the batteries.

Step 16. Place the probe tips on the terminals of the heating element (one probe on each screw)

Read the measure. Check if a multiplier symbol (“K” or “M”) appears on the display, so you can be sure that the measured value is expressed in Ohms, and not in Kilo Ohm (K) or Mega Ohm (M).

In the figure below the display indicates a resistance of 12.5 Ohm, which is to be considered good, since it falls within the limits of the calculated value of 12.2. Ohm

Step 17. Please note that if the heating element is good, the detected value will be very low (between 10 and 20 ohms depending on the power of the element, and possibly detected as zero ohms, depending on your measuring instrument)

To determine the resistance value of a working element, use this online calculator. Enter the voltage value (probably 240) and the power value (probably in the 1000-5000 range) found on the water heater plate, and then press the "Calculate" button.

The image shows an example of a plate with the technical data of the water heater; two power indications are given (4500/4500 and 3500/3500). The indication "4500/4500" represents the power, respectively, of the upper and lower elements, when connected to a power supply of 240 volts. Alternatively, the indication "3500/3500" represents the power, respectively, of the upper and lower elements when connected to a 208 volt power supply. Most domestic water heaters use a 240 volt power supply, but you can also find 208 or 120 volt appliances

Step 18. Check for a grounded item

Prepare the multimeter by setting it to the highest resistance values.

Step 19. Hold the probes together, tip side

The analog multimeter or voltmeter should move towards the lower resistance values (far right). A digital multimeter should read “0” or a very low number close to zero. Find the zero adjustment knob and turn it so that you have a reading of zero (or as close as possible); many tools may not have this functionality. This position indicates, for the selected resistance range, a "Short Circuit" or "Zero Ohm". Always reset the instrument when you change the resistance range.

Step 20. Place the red probe on each of the heating element terminal screws

Keep the black probe well pressed on the metal tank or on the bolts that secure the heating element (not on the terminal screws). Scrape the metal to ensure good contact. The instrument should now indicate an infinite value, as described earlier in preparing the instrument. If the instrument shows a reading other than a very high value (in the order of millions of ohms), or preferably infinite, the element must be replaced, as described below.

Step 21. Reconnect the cables that were disconnected from the heating element to carry out the resistance check described in the previous step

Step 22. Repeat the steps necessary to gain access to the lower thermostat and the heating element

• Remove the bottom panel, in order to have access to the protective plastic element:

  

• Remove the cover as you did for the top panel so that you have access to the terminals. Note that there is no reset button (upper limit) like in the top panel:

  

Step 23. Set the thermostat below the minimum value

Step 24. Set the thermostat above the maximum value

Step 25. In the steps below, it is assumed that there is hot water in the tank

If there is cold or very hot water in the tank, it may be difficult to obtain the expected changes when selecting different thermostat temperature values.

Step 26. Turn the water heater power back on

The following steps require the water heater to be powered to perform the tests. Be very careful, as the risk of electric shock is much higher in this case. Make sure that all cables are reconnected to their respective terminals and that there are no "accidental conductors" anywhere that could cause a shock or short circuit.

Step 27. Remove the red probe from the “Ohm” or “Resistance” terminal of the multimeter and insert it into the “Volt” terminal

Step 28. Set the range of your measuring instrument to the lowest voltage value that is greater than 240 Volt "AC" or "VAC"

As mentioned earlier, the typical voltages of domestic (and mobile / RV) water heaters are 120, 208 and 240 Volts and, of these, 240 Volts is the most used. When we talk about “Line Voltage” in the next steps, you will need to consider the voltage of your particular water heater.

Step 29. Check the presence of line voltage on the upper terminals of the heating element by connecting the probe tip to each terminal as done previously for the resistance test

In the United States, the line voltage is 120, 208, or 240 volts. In Italy it is generally 230 Volts.

The line voltage, in our example, is 208 volts (since 203 is very close to 208); this example indicates a full power available for the element and, if it has also passed the previous resistance test, then it means that it is able to heat the water in the tank

Step 30. If there is no power, try resetting the high temperature switch

It is a red or black button, positioned above the thermostat. Very often it shows the word "RESET"; press it GENTLY but firmly, with a screwdriver or pencil. If it clicks, you should hear a mechanical click. A tripped high temperature switch indicates it will not open. More details are given in the next steps.

Step 31. After the reset attempt, check again for the presence of power on the heating element

Step 32. If there is still no power, check the presence of line voltage on the upper left and right terminals of the high temperature switch, using the probe tips

Step 33. If there is no power, the problem is an open circuit

Check the wiring compartment of the water heater (usually located at the top), along the entire length of the cable that powers the heater and up to the inside of the electrical panel. Remember that, unless the power supply on the panel is off, this circuit is powered at some point between the fuse or switch and the water heater. Tighten all the connecting screws of the electrical cables and the connections inside the wiring compartment, such as all the junction boxes between this point and the terminals of the switch or fuse in the electrical panel. Replace blown fuses or any breakers that have tripped. Check if there is power on the fuse or on the circuit breaker. A circuit switch that trips immediately after a reset indicates a short circuit or, alternatively (although less likely), a defect in the switch itself. 34 Once the voltage on the upper terminals of the high temperature switch has been restored, check the line voltage on the upper terminals of the heating element.

Read the rest of this step slowly and carefully (more than once if necessary) until you understand exactly, as it explains how and why thermostats work together. The key point is to understand how the two thermostats interact and their different functions. The upper thermostat has two positions (it can switch the voltage in one position or the other): (position 1) towards the upper element or (position 2) towards the lower thermostat. The lower thermostat also has two positions, but they are "On and Off", and not one or the other like the upper thermostat: (position 1) towards the lower element, or (position 2) to prevent the voltage from reach the lower element or any other point in that direction. To ensure that the upper element receives voltage to heat the water, the water temperature in the upper part of the tank must be lower than the temperature set on the upper thermostat. Once the water in the upper part of the tank has reached the temperature value set on the upper thermostat, the upper thermostat (which considers its condition satisfied) switches the power supply from the upper element to the lower thermostat. If the water temperature in the lower part of the tank is higher than the temperature set on the lower thermostat, the lower thermostat remains off, preventing the voltage from reaching the lower part of the heating element. If, however, the water temperature in the lower part of the tank is lower than the temperature set on the lower thermostat, the thermostat switches to the "On" position and sends voltage to the lower part of the heating element (a thermostat that switches the voltage towards the heating element or towards the cooling compressor, it is said to be “Caller”) by heating the water. The voltage will remain on the lower element until: (a) the condition on the lower thermostat is satisfied, (b) the upper thermostat detects that the water temperature in the upper part of the tank has dropped below the value set on the upper thermostat. When this occurs, the upper thermostat switches the power supply from the lower thermostat to the upper part of the heating element. This process continues until the water temperature, in both halves of the tank, coincides with the settings of the relative thermostats. Setting the upper thermostat to a higher temperature will not produce the ignition of the upper element if the water temperature, in the upper part of the tank, is higher than the highest possible setting on the thermostat. In this case, you will not hear any "Click" when setting high or low temperature values. It will be necessary to lower the temperature of the water in the tank. The easiest and fastest way to do this is to allow the hot water to come out by opening the hot water tap. The cold water will enter from the lower part of the tank, mixing with the hot water and lowering the general temperature. 35 If there is no line voltage on the element and the upper part of the tank is cold, replace the upper controls.

36 Set the thermostat above the minimum value.

37 Set the thermostat lower than the maximum value.

38 Check for the presence of line voltage in the lower part of the heating element.

39 If there is no power supply, find the electric wire that connects the terminal screws of the heating element with the terminal screws of the lower thermostat.

These will be the common terminals. The other screws of the thermostat and the heating element will instead be the power supply terminals. Connect the red probe to the screw of the heating element power terminal and the black probe to the screw of the thermostat power terminal. You should detect the line voltage. 40 If no line voltage is detected, replace the upper controls.

41 If you still do not detect line voltage, check the presence of line voltage on the screws of the heating element terminals, connecting each probe to its terminals.

42 If there is no line voltage and the tank is cold, replace the bottom thermostat.

43 If you do not detect line voltage, wait for the water to heat up or test the resistance (or Ohm) on the elements once again, with the power off.

If you detect voltage on the heating element, the water should heat up, unless the heating element is faulty. 44 Reset all thermostats to the same temperature value of your choice, but not higher than 140 degrees to avoid the risk of burns.

While at 212 degrees the water boils, a temperature of 150 degrees can cause a burn in a few seconds. When the water is 120 degrees (only 30 degrees lower), however, it takes 10 minutes. Children's skin is much more sensitive than adult skin, and it is easier to cause burns. Given these premises, a temperature close to 120 degrees is the best solution. Furthermore, lower temperature values result in lower energy consumption. 45 Replace the insulation and access panels.

Part 2 of 3: Replace the Elements

Step 1. Make sure that the power supply of the water heater is off and that there is no power on the fuse, on the switch, or on the "service switch"

Step 2. The heating element extends into the tank and is immersed directly in the water

For this reason, the water level in the tank must be lowered to the point of contact with the element to be removed (otherwise, removing the element, you would have water leaks). If you are not sure how much water you need to eliminate to remove the element, empty the tank completely in order to avoid the risk of leaks.

Step 3. To quickly empty and fill the tank, close the tap that supplies cold water to the water heater

Open the nearest hot water tap to decrease the pressure and allow air to enter the tank. Connect a garden pump to the drain valve at the bottom of the tank and extend the pump to the floor or somewhere else so that it is at a lower level than the drain valve; in fact the tank will continue to empty up to the highest point of the pump tube. Open the drain valve at the bottom of the tank and start emptying it.

Step 4. Close the drain valve when the tank is empty (or emptied to the desired point)

Step 5. Disconnect the cables from the terminals of the heating element

Step 6. The heating element is fixed with one or more methods

The first method involves the use of bolts through the holes in the flange around the element. Just use an adjustable wrench or pliers to remove the 4 bolts and, therefore, the element. The second method consists in screwing a threaded part of the element that is located under the hexagonal-shaped flange. Generally a 1-1 / 2 wrench will do fine. If you don't have a wrench of this size, you can safely use the heating element wrench or the adjustable pliers. Unscrew the element counterclockwise, until it is loosened. so much so that you can continue to unscrew it by hand.

Step 7. Clean the surface of the tank around the opening of the element

It is important that all gasket material, filings and rust are completely removed to leave the surface as smooth as possible. A wire brush or sandpaper should make this job easier.

Step 8. Write down the technical data on the water heater label in order to purchase the correct replacement parts

It is advisable to bring the original items with you for comparison. The upper and lower elements are the same.

Step 9. Install the gasket on the element

Step 10. It is not necessary to add Teflon adhesive tape or hemp on the threads of the new element, unless specified in its instructions for use (especially if the new element is equipped with a gasket)

Step 11. Fix the element on the opening of the tank using the bolts or the thread of the element

Make sure that the element is fixed tightly, otherwise you will have leaks when the tank is full and under pressure. It would be better to tighten these bolts so that the nuts on the rubber are tight. First a bolt, then the opposite one; if necessary repeat the process. Don't over tighten.

Step 12. Make sure that the nearest hot water tap is still open before filling the water heater by opening the cold water valve

At first, you will feel only air coming out of the hot water tap. When the tank begins to fill up, the air will come out of the hot water tap in fits and starts followed by dirty water. Continue to fill the tank until the water discharged from the hot water tap becomes clean and comes out without hiccups (steam or water).

Step 13. Close the hot water tap

Step 14. Look for signs of water leaking from the new element

Tighten until no leaks and then dry. Repeat this step if necessary. If you are unable to stop a leak, you will need to disassemble and clean the tank opening and the element to make sure it is 100% sealed when reinstalled.

Step 15. Connect the electrical cables to the heating element

Before turning on the power, the heating element must be completely submerged in water. If this condition is not verified, the heating element could burn and therefore it will be necessary to replace it again.

Step 16. Turn on the power of the water heater

Step 17. To avoid water hammer and breakage, open the hot water tap at home to allow the pipes to fill up slowly

Start by opening the tap slightly and then increase to the maximum level. Optionally, you can remove the shower phone and sink sprinklers to prevent them from clogging up due to sediment.

Part 3 of 3: Replace the Controls

Step 1. Make sure that the power supply of the water heater is turned off

Step 2. Don't the tank needs to be empty to replace the controls.

Step 3. Identify the cables and their terminals

Label the cables and terminals by 1) writing numbers on adhesive tape and applying them to the cables 2) applying different colored tape to the terminals and cables or 3) identifying them differently before disconnecting them.

Step 4. The controls are fixed to the tank by means of steel spring clips

No screws are used. To remove the controls, after removing the electrical wires, lift the clip tabs on both sides of the control slightly and then slide the control out. Excessive force on the tabs can damage them and prevent proper housing of the control. If the control is not properly seated, it may not sense the tank temperature, as operation is based on physical contact and direct heat transfer with the tank. By removing the control from the tank and testing it, you will ensure that the tank temperatures have not caused the water heater to shut down normally.

Step 5. Write down the technical data on the water heater label to purchase the correct replacement parts

It may be helpful to bring the old controls with you so that you can compare them directly with the new ones.

Step 6. Clean the surface of the tank in contact with the controls

Remove traces of rust, dirt and debris.

Step 7. Slide the controls under the steel clip and make sure we are snug against the surface of the tank

Step 8. Connect the controls based on the labels applied before removing the old controls

Advice

• Owners of 120, 208 and 240 volt water heaters will have to consider these values whenever the term "line voltage" is used in the article. The same goes for water heaters with other voltage values.
• If you run into any further problems, click on the "Discussion" button at the top of the page for more information or help.
• This is a good opportunity to clean the water heater. Read also How to Empty a Heater.
• The procedure described in this article can be applied to any electric water heater that was previously functional (which indicates that something broke after installation). A new water heater may fail due to poor factory check prior to release or incorrect wiring. Just because it's new doesn't mean it's functional. Another problem is the connections. Loose or broken connections are a source of malfunctions. With the power off, check that all terminals are well tightened. In addition, touch or move a little each electric wire inserted in the terminals and on the fixing screws to make sure that it is not broken and that it enters under the relative screw or the terminal cap.
• If you are unable to carry out these checks or if you prefer to do others, then contact a professional. You should contact an electrician if the tank is electric but does not have any leaks. Instead, you should contact a plumber in the case of a gas water heater, if it is integrated into the heating system or if the tank (both electric and other) is broken (leaking water) and needs to be replaced. Most plumbers do not have the necessary equipment to detect a problem with the hot water of an electric water heater. Plumbers often disconnect the old one and connect the new water heater power supply, although this operation, in many cases, is to be considered as a violation of the electrical engineering code.
• Use the wiring diagram supplied with the water heater (or attached above) for clarification (when possible). If you are unable to find the diagram, contact the water heater manufacturer or check these wiring diagrams, which are representative of the most common household electric water heaters.
• Get familiar with the use of the multimeter before starting. Different instruments have different ways of measuring voltage and resistance. Some have specific terminals to connect the probes according to the type of measurement to be made, while others have only two terminals to be used for any type of measurement. Regardless of the instrument, be sure to correctly select the type of measurement, the ranges of values, and to connect the appropriate terminals before contacting the probes with a powered circuit. An instrument set to read the resistance, but connected to a powered circuit, can cause damage to the instrument itself and injury to the operator.

• 

  An Amprobe clamp on ammeter indicates a 15.9 amp heating element load. This is within 10% of the 16.9 amp value calculated in a previous step. This lets the user know that this half of the water heater is working properly, and that troubleshooting should continue with the other control and element. Most professional electricians have ammeters with clamps that allow you to speed up the process of identifying the problem. This type of instrument, in general, is much more expensive than a multimeter and, therefore, is not owned by ordinary people. Many of these instruments are able to perform both voltage and resistance measurements (but have a lower accuracy and variety of ranges available than a multimeter), as well as current. Some work only with direct current (DC) or alternating current (AC); therefore, if you are thinking of buying it, make sure it is able to perform the test you need. Current (measured in amperes) is the result of the circuit voltage and resistance. If there is no voltage or resistance, no current will travel. A current measurement combines voltage and resistance measurements, without the need to remove wires, zero and change ranges, and move the multimeter's probes. It can be done as follows: increase the temperature of the upper thermostat and decrease that of the lower thermostat; at this point, connect the instrument to one of the electrical cables connected to the upper part of the heating element. Do not disconnect any cables, because power is required. Read the amount of current shown on the display, then, lower the temperature of the upper thermostat and raise that of the lower thermostat; check the current, as done before, on the lower part of the element. The two measurements should be almost the same (with a 10% difference). The difference may be caused by the heat of the element, which changes the resistance (as discussed above). A change in the resistance of the element will also change the expected current. If one reading is, on the other hand, significantly lower than the other or very close to zero, then half of your water heater is faulty (a problem on the controls or on the heating element). If you read zero in both cases, probably the high temperature switch is faulty in the presence of power in the water heater. Use the multimeter's resistance and voltage reading functions to narrow down the range of possible faults.

Warnings

• The voltage present when the power is on is lethal. Be very careful when working on powered circuits.
• If you do a resistance test with a multimeter or voltmeter without setting it correctly, you can damage the meter, burn yourself, or get shocked. Learn how to use the multimeter's value ranges and make connections to its terminals by reading the user manual.
• Tests with the power on should only be carried out if strictly necessary.
• When taking measurements on the multimeter, pay attention to the multiplier symbols (“K” or “M” on the display). Make sure that the value you read is not to be multiplied by 1,000 (multiplier "K" or kilo) or 1,000,000 (multiplier "M" or mega). Get in the habit of checking for a multiplier when reading measurements.
• The replacement of parts must be carried out in the absence of power supply. The replacement of the heating elements must take place with a level of water in the tank below the heating element, otherwise you will have water leaks as soon as you start unscrewing the element.
• A high temperature switch that clicks more than twice indicates that the thermostat is unable to open, providing, more than necessary, the power supply to the heating element to increase the water temperature. If you follow the steps in this article, you will locate the defective part and be able to replace it. A faulty thermostat, stuck in the "Off" position, will significantly raise the water temperature, increasing the likelihood of burns and scalds.