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How to check the water heater heating element without removing it

Ways to check the heating element on water heaters

Of all the components inside the boiler, the electric tube heater is the most subject to malfunction and breakdown. Before you check the functioning of this component, you need to calculate the resistance. It is calculated as the square of the line voltage and the power output of the appliance, indicated on the case. After that you can measure the resistance of the water heater’s heating elements with a measuring instrument.

The device includes one or more strands of the heating element, mounted in a tube of metal filled with insulating material that conducts heat well. The trouble-free operation of the heating elements is due to the fact that they are under the heaviest load. In addition, a lot of scale is deposited on the element, which negatively affects the quality of operation.

The last phenomenon is less common than the first two, but is the most dangerous: if the heater is not equipped with a safety disconnect device, the user can get an electric shock. If a safety system is installed, the appliance will simply shut off.

To keep the heater in service longer, it should be regularly cleaned of limescale and dirt, and tested with a tester when problems occur.

Multimeter models

To find out the resistance of the heating element is common by means of multimeters. There are digital and analog devices. They are used for similar purposes, but the functional principle is different. Regardless of the option chosen to test the heater, before using it, make sure that the continuity (including damage to the insulation coating) of the wires leading from the probes to the unit to be tested is not compromised.


When purchasing a new meter, it is preferable to choose models of this group. The design includes a controller, an integrated circuit, and a screen that displays the measurement result. These products outperform analog products in terms of accuracy. It is not defined by a zero adjustment or low battery level. the user simply receives a numerical reading. Some products are equipped with additional functionality. with their help you can find out where the wiring is hidden in the thickness of the wall, to test radio components. If heating elements testing is a part of professional activity, it is recommended to buy a device equipped with an alarm. The integrity of the electrical circuit is detected by an audio signal.


These devices are directly connected to the test object. Radio cells convert the signal into an electric current that moves a pointer pointer placed in a magnetic field. Operation of the device requires the polarity to be precisely correct. When an error occurs, the pointer moves in the opposite direction until it meets the limiter and the multimeter can fail if the signal value is significant in modulo. If such a mistake is made when handling a digital device, it will notify the user with a “minus” sign on the display before the numerical value of the measured parameter.

What does a device for water heating consist of?

Looking closely at the water heater from the inside and getting acquainted with its principle of operation, you can find great similarities with an ordinary electric kettle. both have a heating element heater.

Exploring the modern market, there are many boilers with different design, technical characteristics and initial cost.

Important! In order not to get into a misunderstanding, you should buy a boiler only from a reputable manufacturer. on the advice of friends or professionals.

  • The body. the insulated casing of the boiler keeps the temperature of the water several times longer.
  • The heating element. there are two types of heating elements: dry and wet. The first one works by coming in direct contact with water. The second is insulated with a ceramic shell.
  • Accumulation tank. the volume can vary from 15 to 200 liters.
  • Thermostat. when the water temperature drops, the device gives a signal and starts the heating element.
  • Anode. a structural element that provides protection against corrosion.

Magnesium anode or sacrificial electrode is the part of the device that needs to be periodically replaced. Thanks to this, the service life of the water heater, increases by several years.

How the water heater works

The design of the device for heating water is presented in the form of two tanks, insulated from each other. Stainless steel is used for the main tank to reduce the risk of corrosion. Between the tanks, the void is filled with a heat insulator that can retain the heat coming from the heated liquid.

This feature allows you to reduce heat loss to a minimum. The benefit of this is very noticeable when suddenly the gas or electricity is cut and the owner, after returning home from work, wants to take a shower. If the water is deprived of the possibility of heating, its temperature, can retain suitable indicators for use, within two to three days.

Under normal conditions, a decrease in water temperature below the manufacturer’s set points causes the heating element to turn on.

The design of the device is arranged in such a way as to eliminate the possibility of mixing of cold and hot water during its use. Since cold water is heavier than hot water, it is constantly at the bottom. Therefore, the engineers placed the supply pipe in this part of the heater, and the outlet hole for the output of the hot liquid, at the top of the device.

In the same way the displacement of hot water with cold water takes place. After turning on the faucet, the pump starts, feeding the cold water into the inlet spigot. Water entering the tank, under the influence of the natural laws of physics, pushes out the hot.

After installing the appliance, it is recommended to adjust the thermostat to a temperature of 60oC. Such prudence will reduce the risk of scale formation on the inner walls of the tank and heating Tengx.

Important! In order to kill the bacteria inside the tank, it is recommended that you run the device at full power once a month.

What you need to know before measuring?

If you have a multimeter, you can test the heater of a broken appliance yourself.

But first you will need to find the technical data sheet of the defective product and find out the rated value of its heater.

This is important, because to test the electric heater we will need to know the nominal value of its resistance, which is calculated from the formula of the basic law of Ohm:

where R is the required electrical resistance (Ohm);

The operating voltage of the home electrical system is mostly 220 V. The power of the heater can be found out from the passport data of the household appliance (W). Resistance value is given in ohms. Now it is possible to test the electric heater.

Checking the heater with a multimeter

To begin the testing process, you must first secure your work by disconnecting the household appliance from the mains. You just need to pull the power cord out of the socket, and for an electric stove with a separate line, perhaps disconnect the breaker in the apartment electrical switchboard. In any case it is necessary to de-energize the equipment.

Further it will be correct to act according to the following algorithm.

  • Provide access to the terminals of the electric heater. In some cases it may be necessary to remove the heating element completely from the unit for ease of testing.
  • Prepare a tester (multimeter) by switching it to electrical resistance measurement mode. Measurement range should be chosen depending on the result obtained, which we calculated according to the formula of nominal resistance for the heater of your equipment.
  • Firstly it is necessary to test heater pins, for what we touch them with the device probes and look at the result. The coil is functional if the tester readings are within the calculated resistance. If the meter shows infinity (∞) or one (1), it means that the heater element has a breakdown and must be replaced. In case of internal short circuit the tester will show 0 (Also need to replace the heating element). In models of heaters with several spirals, it is necessary to test each pair of outputs separately.
  • Then check the absence of breakdown of the insulation layer of the coil on the body. Mode of the tester is switched to “Buzzer”. One of the device probes should be short-circuited to the body of the water heater, and the other probe should touch the coil leads in turn. In case of breakdown there will be a signal, but if the heater is in good order no sound should be heard. If there is a breakdown the heater should be replaced with a new one.
  • If there is no damage to the tube heater you should look for other reasons. For example, to check the cord or line for trimmer of the electric power supply of household appliances, if it does not have any signs of “life” at all; the thermostat in cases of underheating of water or early switching off of the electric heating element. The thermostat can be tested with the same multimeter by removing it from the mounting location and disconnecting all wires. Then set the tester to the “probe” mode and touch the two terminals with the probe. If there is contact, then check the operation by dipping the regulator’s stem into the water at the maximum temperature (the multimeter should be connected to the terminals). When reaching the heating limit, the thermostat should open the circuit contacts, which will be indicated by a characteristic click. When the water cools down, the thermostat will restore the electrical circuit. another “click” will sound when the relay contacts close. All this will indicate the correct operation of the thermostat.

With a multimeter you can check the condition of electric heaters of almost all types of domestic water heating appliances. And the algorithm of actions does not differ from the above-mentioned one.

There are only some nuances of its extraction. But we must remember that it is not necessary to remove the heating element for checking, if the contacts are freely accessible. The washing machines have difficulties in determining the location of both the tube heater and its thermostat. But in cases, when in the accompanying documentation there is no information about the location of these elements, by the brand of the machine you can find its detailed device on the Internet.

Checking the heating element on the high power water heater (boiler) is also not different from the check that we have already described, but here, along with the heating element, you must check the thermostat with a sensor.

Diagnostics of the heating element condition using multimeter

You can check the heater element of the boiler for breakage using a multimeter. Disconnect the water heater from the power supply, disconnect the cords from the electric tube heater connectors. Clean the fuel element from scale deposits beforehand (this can be done with a solution of citric acid).

Next, perform measurements. It is necessary to follow a certain order of action:

  • adjust the multimeter by setting the resistance value in the range of 200 Ohm;
  • touch the terminals of the heating element with the tentacle of the device;
  • if the heating unit is working, the resistance value will be close to the calculated value;
  • zero on the scale means that there is a short circuit inside the device, and it must be replaced;
  • the unit indicates that the heating thread is broken.

Then it is required to check whether there is a breakdown of the heating element, going to the body of the water heater. To do this, follow the algorithm:

  • switch the tester to operate in sound mode;
  • touch the boiler body with one lead of the tester (you can touch the terminal that connects TEN and ground wires), and with the other lead touch the heating element;
  • if there is a sound signal it means that there is a breakdown in the heater, i.e. the device must be replaced.

Other ways to test the heating element

You can check the efficiency of the electric tube heater without using a tester or multimeter. To do this, you need to apply the control light bulb:

  • connect one contact of the heating element to the power supply;
  • Connect the second contact to the electrician’s bulb;
  • If the bulb lights up, it means that there is no breakage of the heating element.

Another affordable way to check the heating element on the water heater for proper operation is to use an indicator screwdriver. It is not necessary to remove the heating element from the boiler:

  • disconnect foreign wires;
  • touch one contact of the element with your finger, touch the other contact with a screwdriver;
  • with the finger of the other hand simultaneously touch the metal point on the handle of the screwdriver;
  • if the indicator light is on, you can be sure that there is no breakage.

Over the period of operation of the water heater, the insulating material inside the heating element deteriorates. This causes the current to flow to some extent to the body (you can feel the electric shock when you touch the body of the boiler). The resistance of the insulating material of the heating element in this situation can be measured with a megohmmeter: set the range to 500 V on the device; touch the contact of the heating element with one probe, with another. the body of the water heater.

It is possible, when in the same circuit with the heating element installed trip protection device (RCD). If the condition of the insulation inside the electric tube heater is poor, the level of current leakage may be such that the RCD will trip. Multimeter when checking such faults will not show, since there is no short circuit on the body.

How to use a multimeter

The process of diagnostics can not be started if the boiler is connected to the network. Remove the plug from the socket, turn off the automatic device, and only then begin to work.

Disconnection of wires

  • Reset the power and ground terminals.
  • Disconnect wires of different colors: blue, brown, yellow.
  • Probe each wire to see if there is a breakdown or short in them. If the resistance value is normal, check for a shorted coil to ground. When the resistance values are not the same as specified in the specifications of the device, it means that there is a short circuit in the tube.

Cleaning joints

The tester will not show the correct value if the terminals are not clean. Therefore, before testing, you should clean the terminals of plaque, rust, especially in places where the multimeter probes will be attached. If heavily contaminated, sandpaper may be needed. Clean surfaces need to be polished to a shine.

Peculiarities of checking the safety valve

High pressure in the boiler leads to the failure of many parts of the device, to save the water heater from them helps to install a safety valve. The valve opens during operation, the excess water flows out, allowing the pressure to return to normal. This is accomplished by a spring mechanism built into the valve.

Diagnostics of the given unit consists in defining features of excessive liquid leakage. The normal state of the device is indicated by the liquid dripping when the device is heated. If water does not flow at all or flows in a trickle, it means that the electric tube heater is broken.

To get rid of the fault will help a tap-connector, thanks to which it is possible to drain the resource from the vessel.

How to test for breakdowns?

The breakdown test is an insulation resistance test. Ideally, the insulation should not be less than a few meg ohms. Testing for breakdown in any of the places is carried out by striking the current from the body of the CMA and / or by triggering RCD. Put one probe of the multimeter to any of the contacts, the second probe. to the body of the boiling water heater. Resistance value below 20 ohm, tending to zero, indicates the case short circuit. A heating element “punctured” in the case cannot be used.

Breakdown occurs when a dielectric layer is burned out from the heated coil, which can be quartz, mica, heat-resistant and heat-resistant clay such as that used to make fire bricks, etc.

This insulator fills the entire inner free part of the boilers, preventing the coil from making contact with the outer steel casing.

Professionals use mega- and gigaohmmeters, which operate at a supply voltage of 500-2500 volts. These high-voltage testers are not always available to the average consumer. Wearing dielectric gloves is recommended.

The breakdown test both with the tester and megohmmeter is carried out on the washing machine with the obligatory disconnection of the terminals and de-energizing of the whole machine; in this case the protection against electric shock is not required.

The fact is that ordinary testers only produce voltages up to a few volts. it is not dangerous for unprotected hands, if they do not have wounds. It is recommended to switch the tester to the highest measuring range, up to 2 megohms.

How to determine resistance readings?

To check the heater you will need to calculate the resistance according to the following algorithm, based on the school physics course.

  • The voltage in the network. about 220 V.
  • The power of the heater is indicated in the manual for this washing machine.
  • To calculate the resistance is possible by dividing the square of the voltage value by the declared power. So, for a power of 1800 W, the coil resistance is 26,8 Ohm. If this value (or the one closest to it) is displayed on the device, the operability of the heating element is evident.

This is the working resistance of the boilers. This is what determines the current load of the electric line for the trimmer, suitable for the washing machine. without taking into account the power consumption from other units and assemblies of the unit.

All of the above methods of checking the heating element will work with any heating appliance where it is used. from irons to clothes dryers.

The heating element is very easy to check. Even without a device you can detect with a high degree of probability that it is broken. Replacing a damaged heater is an even easier step than diagnosing it.

How to test the heating element in a water heater or boiler?

The first step is to check the continuity of the heater filament with an ohmmeter. Often electric elements have a resistance of several tens of ohms. To do this, you need to get to the heater and measure the resistance on its leads. We have at hand the heating element from an old boiler, using it as an example and we will conduct the test.

To check the integrity it is not always necessary to remove the heating element completely, it is enough to connect the device to the contacts.

If the coil is intact, the next step is to check for breakdowns. If the heater has a ground fault, it is no longer safe to use.

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If you don’t have a multimeter or a dial, you can check the heater with a light bulb connected in series to the heater.

How to check the heating element with a tester?

If you do not have a digital multimeter handy, you can use a dial tester. The test principle is the same. It is quite easy to determine the good condition of the coil by the deflection of the needle. For illustration, use a tester to check the dryer heater. Alas, the heater in this dryer is not working, as you can see.

Checking the safety valve of the water heater

Before checking the serviceability of the safety valve, the appliance must be switched off. Do not open the hot water tap until it reaches the maximum temperature. If the valve is working properly, extra water will drip from it. If it does not, it must be replaced. But before that, check the condition of the faucet. If it is leaking, the reason of water dripping is hidden in it, the valve does not work as well.

Safety valve does not work and at a wrong thermostat, that is, it is set to incomplete heating or water is taken from the water heater tank, which leads to a decrease in pressure. It is forbidden to replace the safety valve with the reverse valve.

Checking the water heater heater heater

Tubular electric heating element can be checked in different ways.

Checking the water heater heater heater without a tester

Visually inspect. Remove the plug, check for limescale or damage of any kind. When diagnosing the electric heater the places, where the multimeter probes are fixed, should be cleaned from lime scale, rust, dirt. It is possible to remove accumulated scale by soaking the heater for 5-6 hours in a solution of citric acid. If the element is heavily contaminated or the contacts of threaded terminals are not fixed enough, they will burn. Grind the metal at the connection points of the probes. It is necessary to know how to properly remove the faulty heater and install a new one.

Using a multimeter

Before you check the water heater heater heater with a multimeter for serviceability, it is necessary to look at the nominal value of its power in the technical passport. Pull out the plug before starting the test. It is necessary that the leads of the electric heater can be approached. Sometimes it is more convenient to work with the heater completely removed. Disconnect wires from it. Look for any damages, bumps and cracks. Switch the tester to the resistance measurement mode. The regulator on it is set to 200 Ohm. Connect the styli of the multimeter to the leads of the electric heater.

Coil malfunction can be judged when the device screen displays the value. 0, 1 or infinity.

After the water heater is checked with a multimeter, check the case for breakdown, switching the tester to the buzzer mode. One probe should be connected to the case or grounding terminal, the other one to the electric heater. If the device beeps. Do not touch the heater when it is switched on.

If the device is absolutely faultless the resistance value will appear on the screen, which is calculated in advance according to the formula R=U/P.

U. constant value equal to 220 volt. P. boiler power, indicated in the operation manual. It can be found on a sticker glued on the back or on the bottom of the appliance.

If the electric tube heater does not have any damage, it is worth checking the line for the electric power trimmer and the wire.

How to check water heater heating elements plus servicing.

If the thermostat is broken, the heating element shuts off early and the water does not heat up to the correct temperature. To test the trimmer, remove it and disconnect all wires. Put the multimeter on the probing mode, touch each of the terminals with the probe. If there is contact, its functionality can be checked with a tester with terminals connected by lowering the regulator’s rod into the hottest water. As soon as the maximum temperature is reached, you should hear a “click” sound, which indicates that the regulator’s temperature sensor has opened the circuit contacts. The water will cool down, and he will restore the circuitry. Relay contacts close. which can be judged by the clicking sound heard again. If this happens, it means that the thermostat is in good condition.

Ringing with a megohmmeter

If there is current leakage on the equipment body, you can only use an megohmmeter. a device that measures insulation resistance. It can be used to make sure that the insulating material is still intact and also to measure accurately. Over time, the insulation will age and the leakage current will increase. This can have serious consequences. Set the megohmmeter to 500 V. Connect one lead to the contact of the heating element and the other lead to the housing. If the gauge reads above 0.5 MOhm, the heater is working.

With an avmeter

An ammeter is a combination meter designed to measure DC current, voltage, and resistance. To check the efficiency of the heater with an avometer, the heater is disconnected from the mains. Remove the protective cover. Disconnect the wires that go to the heating element. Connect the heater terminals to the device. Write down the readings and check them against those in the data sheet.

Check with a tester

If you don’t have a tester you can use an indicator light. To one contact connect the zero from the mains, to the other. the phase, passed through the bulb wire. If it lights up, there is no breakage, the circuit is normal.

You can use an indicator light for checking

Why the heating elements in the water heater burn

“Wet” heating elements burn from overheating caused by limescale. Sign when the thickness of foreign layer is critical. hissing, whistling when heated.

Immersion heaters burn out more often. Limescale serves as an additional thermal insulator: 1 mm gives an additional 75% of thermal insulation, overheating is dangerous because it is permanent. Filament and other elements of the heater are designed for a certain operating temperature, at a different value their service life is reduced.

Burnout of “dry” heaters is not due to scale, the cause may be a breakdown of electrical elements from the age, short circuits, voltage spikes, loss of contacts.

How to check if the heating element is working properly

Analyze electrical parameters. Checking the water heater’s heating element with a multimeter:

Example: Heating element is 1,3 kW (1300 W, Watt), line voltage is 220 V (Volt):

  • the value is close to the calculated one. serviceability;
  • zero. there is a short circuit inside, malfunction;
  • 1 (tester with an arrow will show ∞). breakage of electrical contacts, spiral.

Next, you must test with a multimeter to see if there is a breakdown on the housing (to probe the heating element):

  • the switch is set on the diode, “buzzer”;
  • one probe to the output, the second probe to the body (it is possible to connect to the “ground”);
  • There is an audible signal (beeping). there is a breakdown.

To check the efficiency of the heating element when the insulation is damaged, use a megohmmeter. Failure can occur both from mechanical damage and from aging materials. There is a leakage current on the housing.

If the circuit with the heater has a RCD (protective shutdown, the recommended value for boilers is not max 30 mA, and max 10 mA), then if the insulation is damaged, the water heater turns off all the time. Protection is activated with half the current for tripping: from 5 mA for RCDs at 10 mA setting, from 15 mA for 30 mA.

Set the range of 500 V on the megohmmeter. Touch the probes to the terminals and the housing, the normal value is greater than 0.5 Ohm.

The defect may not be in the heating element itself, it is also important to check the thermostat (if present), usually it can be disconnected without complicated manipulation.

The thermostat is either in the base of the heater as part of its construction, or in the tank itself under the control box cover. In the latter case, you do not have to drain the water. just remove the panel and this unit. Replacement procedure is simple. insert a new one, connect all wires correctly. The test process is standard. using a multimeter.


After performing the test and determining the nature of the fault of the heating element, in which it is necessary to replace the part, you should proceed to the task at hand. The algorithm of its implementation consists of several consecutive steps.

  • The first step is to disconnect the appliance from the electricity supply.
  • Next you need to drain all the water that is in the tank.
  • Then you should remove the water heater from its mountings to ensure the most comfortable conditions for repair work.
  • To gain access to the heating element, which is located inside the boiler, you need to unscrew the fastening of the lower bar of the device. Before dismantling anything, it is better to take a picture of the original location of the wiring. This will make it easier to reassemble after replacing the failed part.
  • The next step is to disconnect all wires that lead to the heating element.
  • The part can then be removed from the vessel.
  • In some cases, after cleaning the tubular part from plaque (if the body is intact), you can try to install the cleaned element back. Often such manipulations help to restore the device operation.
  • If the described method does not bring results, it is necessary to install a new heating element.
  • After that you need to reassemble the body of the tank in the reverse order.


Since most apartments and houses, where water heating tanks are used, receives hard water from the central water supply system, on the wet-type heating elements over time, plaque and scaling will form. Such neoplasms partially block the conduction of heat or exclude it altogether. Elements burn but do not heat the liquid in the tank.

The first obvious sign that the part has accumulated plaque is an increase in the amount of electricity consumed by the device.

If you do not react to such alarms in time, the small crust can reach a large size. In addition, it will gradually grow over the entire surface of the heating part.

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Water Heater Not Heating? Heating Element Testing

The main threat posed by plaque is that it can completely seal the heating element. In the course of working with such a crust it will heat up even more. As a result, either the device will burn out, or the protective relay will be triggered, and the water heater will shut down.

Periodic cleaning will save money and prolong the life of the part. To solve such a problem, you can use one of the cleaning options:

In the first case, work should be carried out with a damp part, as this will facilitate the process of descaling. During the mechanical cleaning a hard iron brush or a knife is used. When cleaning the scale, all safety precautions must be observed and care must be taken not to damage the base of the element. After performing this cleaning, the surface of the heating element is sanded down with a sandpaper.

For chemical cleaning, a large number of household chemicals are available for sale, the main purpose of which is to remove scale and scaling.

The most suitable composition will be a cleaner for electric kettles. The heating element is cleaned in a tank with water and detergent, where it is completely immersed.

There is a more gentle version of the composition for cleaning, it is acetic acid. It should be handled in the same way. To increase the effect, you can put the container with the part on a small fire.

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When cleaning the part, you should avoid contact of chemical compositions with the rubber seal, which is located on the element.

From the impact of aggressive compounds, the material may lose its properties (primarily. elasticity). As a result the heating tank will leak.

On how to replace or clean the heater element with your own hands, watch the following video.



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