Water heater does not turn on after being turned off

Faults of the water heater, causes and solutions with their own hands

Regardless of the brand of water heater and its cost, sooner or later breakdowns occur. Most of them are in no way related to the peculiarities of operation, but it would be foolish to rule out the possibility of malfunction through the fault of the user himself.

Each water heater by virtue of its design features has some kind of breakdowns, but most of them can be prevented or corrected independently. The main thing is to follow clear instructions and observe maximum safety.

The water heater does not work: why, what to do

The situation is quite common: you have turned on the electric heater, after the usual time you open the hot tap, and the water is cold. This may (or may not) be accompanied by additional symptoms:

  • Power indicator (heating, switching on the second circuit) does not light up;
  • The boiler is electrocuted through the water (if it is not grounded. this is not necessarily a sign of malfunction);
  • From the water heater drips (pours) water;
  • Unusual sounds can be heard inside the enclosure;
  • you can smell burnt wiring around the electric water heater;


what to do if the appliance, which worked yesterday, does not give signs of life?

First of all, it is necessary to check the input electric circuits.

  • it sounds banal. but look whether the electricity is off in the house (after turning on the boiler);
  • check the circuit breaker on the line to which the water heater is connected;
  • in 90% of cases (especially if you have a flow-through water heater), connection is made through a RCD: check and this circuit breaker;
  • We look at the temperature set on the thermoregulator (sometimes in a hurry the user forgets to set the desired mode);
  • Inspect the plug and socket of the storage water heater (at a high load it is possible “burning” of contacts).

If the external causes are absent or eliminated (you turned on the machine, etc.), and the water heater still does not work, deal with the electrical device. Of course, you can call a specialist or take the equipment to the workshop. However, this will incur additional costs.

Despite the apparent complexity of the design, water heater repair with their own hands is possible, even in the absence of special equipment. You will need a set of wrenches, a good screwdriver, pliers and a multimeter, you may need a soldering iron.

water, heater, does, turn, turned

If you have it and you know how to use it, chances to fix the boiler by yourself are much more.

Repair of such appliances, although it obeys the general logic, still it will be better to find the original wiring diagrams.

We repair the heater by ourselves

First, determine the reason why the appliance does not work. If there is no leak, you should not hurry to drain the water heater tank. Some elements can be repaired without draining the water. All the more that 80 or 100 liters is not a trifle.

Checking the dryness of the case at the bottom of the boiler. This can be done with gray toilet paper: it literally “shows” the slightest leakage. In some models (such as an Ariston water heater), the bottom cover can trap condensation.

Then you will find leaking points only after removing the bottom of the case.

If the water heater doesn’t leak, check the electrical

  • After removing the panel, first of all “test” the power cable with a multimeter.
  • How to test the control module? Begin with a visual inspection.

Top 10 Water Heater Problems

All connecting tracks on the circuit board must be continuous, there are no signs of charring and thermal darkening on the parts.

For example, diagnosing the boiler “Termex” with their own hands, it is not necessary to remove the heating element. However it is necessary to disconnect all wires from the contacts.The electrical resistance of the tube heater in most cases is about 500 kohms (0.5 mOhm).

How to check the resistance, if there is no possibility to set the exact range in kOhm (mOhm)? Set the multimeter mode switch to the measurement range closest to the actual value. Connect the probes to the contacts of the heater without touching them with your fingers. Otherwise you will introduce an error in the measurement.

In the control unit no malfunction is detected, the wiring and the heating element are intact, and the water heater still does not heat water

The rest of the faults can only be repaired after the water has drained out. There are several ways to do this:

  • You can use the pressure relief valve, or a pre-installed additional faucet. If there is such a shutoff valve on your boiler.
  • On some models there is a third connector for water drainage. It is much easier to repair the boiler with your own hands.

What else can break

If the power lamp is lit, but the water still does not warm up, the cause may be in the pressure sensor (not to be confused with the mechanical safety valve, which is built into the intake pipe). It prevents the tank from deformation in case of overheating of water, if the thermostats are malfunctioning. There is a diaphragm inside the device.

It is the moving part of the sensor that reacts to excess pressure. If the receiving port for the measurement is clogged with scale, the diaphragm does not return to its original position and gives a heating lockout signal. If the hole cannot be cleaned, it must be replaced.

A faulty thermostat can either over or under reading. If in the first case, one of the protection sensors is triggered, in the second case. simply will not heat to a predetermined temperature. Checking this module is difficult.

How to change the thermostat? It is located at the bottom, on the area where the heating element is located.

A separate procedure is to replace the heating element

This is necessary when you are sure the heater is faulty, or if the flange that holds the heater is leaking. In any case, to carry out a revision of the internal space of the boiler does not interfere. At the same time you can clean the heating element from scale.

Of course, this situation is possible only with very calcareous water. But even normal water hardness, and ignoring maintenance, will turn your heater into a useless piece of iron.

As you can see from our material, the water heater repair is possible even at home. But it will be better to prevent the occurrence of failures. It is enough to perform timely maintenance procedures (cleaning, diagnostics), and monitor the quality of water: up to the installation of a filter in front of the heater.

water, heater, does, turn, turned

And remember about the connection of security systems: RCD, grounding, equipotential bonding.

The pledge of long and serviceable service of water heaters Ariston and other firms. timely maintenance, which is recommended to produce at least once a year. When servicing a specialist will conduct a range of work, including replacement of magnesium anode, cleaning the tank and heating elements, as well as diagnostics of electrical systems water heater.

Why do water heater failures occur

Devices with electronic devices are very sensitive to external influences. Malfunctions that can cause the water heater not to turn on can result from:

  • Voltage fluctuations in the power supply. To protect the boiler from breakdowns in such a situation, you can use a special relay that can limit the voltage.
  • Improper operation of the water heater by the owners.
  • Improper installation of the water heater. If the installation of the unit is done incorrectly, even a high-quality device will quickly fail.
  • The formation of a layer of scale and salt on the thermal elements of the heater. This happens when the water temperature in the appliance is high. The optimal heating temperature is 60 degrees Celsius.
  • Untimely replacement of small parts that have become unusable, leads to more problems.

Tip! If the water in the system is hard, you need to install a filter at the inlet to clean it. This limits the penetration of small particles of impurities inside the boiler.

Causes of breakdown of the boiler

When buying a boiler, you should take into account the fact that the high cost of the device is not always a guarantee of long-term operation and absence of breakdowns. However, if they occur, for example, the boiler does not turn on, do not worry. In most cases, you can repair it yourself. It is important only to correctly determine the cause of the breakage.


Before installing the appliance, it is important to study the operating instructions and the technical data sheet. These documents contain a detailed description of the main elements and all the necessary information for its correct use. Manufacturers, as a rule, recommend regular maintenance of the device, but malfunctions of the boiler can still occur.

The main causes of malfunction of the water heater:

  • Lack of voltage in the electrical network or damage to the cable;
  • Improper installation of the boiler;
  • Scale formation on parts and bulb corrosion.
  • Pressure sensor breakage.

Important! Disconnect the boiler from the mains and drain it before proceeding with disassembly.

No voltage in the electric network

The first thing to do is to check the socket by plugging in any other appliance. If it also does not work, it means that the reason is the general lack of electricity. Low voltage in the mains significantly impairs the operation of electrical appliances. Particular attention should be paid to the cable integrity.

Improper water heater installation

It is very important to install the heater correctly. This task must be approached with maximum responsibility. Ideally, it should be done by a professional. An improperly installed boiler may not function properly and can be life threatening to users.

  • The dimensions of the wall on which the boiler will be mounted. It must be able to support the weight of a device filled with water. The water heater is recommended to install on the load-bearing walls.
  • The need for thermal insulation of pipes. High insulation helps maintain a high water temperature, which will reduce the time of water heating and reduce energy costs.
  • The presence of the expansion tank. Water can leak suddenly. The presence of a storage tank will help to avoid flooding of the room with water.
  • Availability of a water heater safety valve. During normal operation, the device heats the water to the desired temperature. However, in the case of failure, the water heater heats to boiling point, and the internal pressure rises significantly. In the absence of a valve, the pressure is not held back. Result: tank rupture with all the ensuing consequences.
  • Installation of grounding in accordance with electrical safety rules.
  • Availability of free space near the water heater for easy maintenance.

Scale formation on parts and corrosion of the bulb

All internal parts of the tank are subject to scaling. Hard water in the water supply consists of many salts that are deposited on the walls of the boiler, the heating element and coil surfaces. Over time, the heating element stops heating water at full power and consumes more electricity to heat water. As a result the energy costs are high and the water temperature is low.

Failure of the water heater and corrosion of the bulb. In this case the corroded tank should be thrown away. Theoretically, you can seal a hole inside the bulb, but this method only temporarily solves the problem.

How to prevent limescale buildup? It is for this purpose in modern devices there is a magnesium anode, which prolongs the life of the boiler. It does not play a role in heating water, but without it the device will not last more than a year on average. The anode actively prevents the formation of limescale deposits. As magnesium ions oxidize in the water, they react and form magnesium salts. Due to their brittleness, they immediately precipitate out, so that no lime scale appears on the heating element. The boiler must be cleaned annually and the used anode replaced with a new one if necessary.

Pressure sensor breakage

The pressure reducer or pressure sensor is a device used to reduce the inlet water pressure and protect devices from water hammer due to momentary changes in water pressure in the system. The consequence of high pressure is a hose burst. Such a shock will cause the rusty pipes to break and the plugs to burst. The average water heater is designed for a water pressure of up to 4 atmospheres. Water pressure of more than 8 atmospheres at the inlet causes the pressure relief valve to malfunction, through which the water starts to drip. An overstretched diaphragm no longer performs its protective function and must be completely replaced.

Socket failure

It happens that the outlet, which powers the boiler, ceases to provide enough voltage, or is simply not compatible with the device. this is a trivial reason that your boiler does not turn on. In the first case, check the functionality of the socket, connecting to it another device. Replace the worn out socket with a new one, or move the boiler to another location.

Remember not to plug appliances into electrical outlets that are not designed for high voltage, as this can cause a short circuit or damage the unit. Among other things, consider the state of the home wiring, because such a powerful electric device will have a serious load on it.

The water heater does not turn on: causes

Of course, troubleshooting in such a complex apparatus, like a water heater, should be made by a master. It should be a qualified person, a professional of his craft, which can not only understand exactly why the boiler does not turn on and does not warm water, but also qualitatively repair the device. But still some manipulations can be done yourself so that you do not spend too much money to call a master. Why can’t the water heater be turned on?? And why it does not heat the water?

So, before carrying out an inspection, the water heater must necessarily be disconnected from the power grid.

The scheme of the electric water heater.

This manipulation is extremely important from a safety point of view. Also it is necessary to drain all the water that is there. Everyone knows the fact that electricity and water. it is definitely a killer “mixture”, and therefore it is not worth the risk, and simply drain the water and de-energize the device.

The first thing to remove is the lid of the unit, under which the board, thermostats and wires are located. This is the structure of a standard water heater. In rare cases, these or other designs may be equipped with something else besides what has been listed. But it does not occur very often.

So, the first cause of water heater malfunction may lie in the electricity. Ideally, current flows through the terminals of the heating elements, thanks to which the water is actually heated. You can find it out with the help of a special tester. It is sold in specialized stores. Sometimes it is included with the boiler itself. With the help of a special tester you can identify the lack of continuity in the supply wires, faults in the contact between the wire and the terminal of the heating element.

It is equally important to check the integrity of the heating elements. Besides, you should identify the presence of holes in the device case. This can also be done with another special tester. The water heater will never work if the coil is damaged. The same applies to the hole in the body.

The main faults of water heaters

To repair the water heater with your own hands is not so easy, as it initially seems: each manufacturer of heating equipment uses different technology, and each of them tries to make something new and unique in their products.

As a result of all this, the diagnosis of malfunction of the water heater of one manufacturer will differ significantly from the diagnosis of the device, issued by another company.

Some of the existing failures can be easily eliminated by yourself, for some of the equipment will have to be taken to a service center.

The main causes of malfunctioning are

Malfunctions rarely occur by themselves, and for each of them there is a different reason:

  • Instability of voltage in the network;
  • Lack of service and preventive maintenance of the equipment;
  • improper installation of the heater;
  • Scale and corrosion formation on the heater elements;
  • The presence of manufacturing defects in the equipment;
  • Lack of timely replacement of damaged parts.

The main malfunctions of water heaters

Leaks in the water heater are often caused by corrosion or a hole in the heater tank itself. Such a tank should be replaced.

Unfortunately, many boiler owners weld leaks in the tanks themselves, dooming themselves to the risk of exploding tank and cause irreparable harm to their health.

You must not weld the tank yourself! Often water starts dripping from water supply joints, rubber hoses or plastic pipes. for this reason these types of connections are categorically not recommended for installation.

If water drips from the safety valve when water is heating it cannot be considered as a malfunction: the liquid expands during heating, an excessive pressure is created in the boiler. But if it leaks too much water (more than one and a half liters per day) or the valve is completely dry. it is broken and must be replaced.

If the boiler has stopped heating water. most likely the heating element is broken because of excess scale on it or a thermostat that has deteriorated because of a critical increase in humidity. The cause of failure can also be hidden in electronic modules, fuses, circuit breakers or an emergency shutoff.

The latter often occurs if the boiler is turned on to operate at maximum temperatures. Another breakdown is a long heating of the water, due to which the water comes not hot, but warm. In this case, could fail the TEN, as well as the thermostat, switch or fuse.

In the reverse situation with excessive overheating of water “guilty” can only be thermostat or electronics.

If hot water is coming into the faucet with a weak head, you need to assess the head of the cold water in the tank, as well as the functionality of the faucet. If both devices work normally, the fuse valve can be defective. clogged with dirt or scaled salts. In that case the valve should be cleaned.

water, heater, does, turn, turned

If the water heater is gas and parapet, in the wintertime its chimney can suffer from the formation of ice. the steam, settling on the grate, turns into ice, which blocks all the ways to remove the smoke. As a result, it will not turn on for more than a few minutes. Removing ice masses will help correct the problem.

When the water heater can heat the surrounding equipment: its plug, socket, walls, and so on.

But if heating the walls is not such a fire hazard, then the socket and plug need attention.

For example, it could be caused by poor contact in the plug itself or in the socket, consuming an amount of electricity that the socket is not designed for. Occasionally it can indicate a broken heating element.

No less rare cause of failure. incorrect operation of the RCD. Low quality heaters, often made in China, use simple, cheap tripping devices that break too often.

If the device trips too often, completely turning off the water heater, the neutral and ground wires may be confused. Often, because of the lack of opportunities to ground the wires, the owners of heaters prefer to “ground” them, applying a kind of quasi-grounding.

In this type of “grounding” conductor “zero” and ground are connected, but RCD does not accept it and shuts down the boiler.

If the heater heats an insufficient amount of water, the cause can be sought in the incorrect installation of the device: the inlet and outlet connections could be mixed up or incorrectly connected.

Malfunctions of heaters ThermexIt is important to distinguish Spanish-made water heaters, which name is written in Latin letters, and the allegedly Russian, but in fact the Chinese Termex heating devices. Spanish boilers are also called Fagor. Thermex water heaters have four main signs of malfunctioning. So, the boiler is broken if:

  • The water takes an excessively long time to heat up, or does not heat up at all;
  • The heater turns on and off too often;
  • While working, the device makes unusual noises;
  • Water from the water heater comes out with an unusual odor or color.

Often these signs, appeared at the heater of Spanish production with a world-famous name, indicate breakage of tubular heater or that on the walls of the tank accumulated a rather large amount of limescale. To return the heater to normal operation, the broken heating element should be replaced, and the tank should be cleaned of solid salts on its walls.

Malfunctions of water heaters AgistonThe water heater produced by this company most often suffers from the following malfunctions:

  • The sensor, the heating element and the switch (each device separately or all at once) are out of order. the reason lies in the breakdown of electronics;
  • If the machine regularly “knocks out”. the water heater does not have enough voltage in the network for normal operation, and to give him the opportunity to heat water, all other devices will have to be turned off;
  • If the device does not work ignition, the reason may be hidden in the power supply. poor-quality extension cords and so on.

Peculiarities of repair and replacement of RCDs

If the automatic device knocks out when you turn on the boiler, there is a high probability of breakage. Faulty RCDs can be repaired with experience, tools, and parts. Optimal solution for owners is to replace the device. To determine its probability, you need a monthly check. To do this, use the button to create an artificial leakage.

Repair work considerations

The difficulty of repair is that there is no circuit. Therefore, when troubleshooting independently should be guided by this algorithm:

  • Removing the sealant and self-tapping screws from the case.
  • Removing the fasteners with a slotted screwdriver and disassembling the device.
  • Making a diagram by drawing from a printed circuit board.
  • Testing the device. The leakage current is simulated by applying voltage from the resistor to the amplifier. The leakage is indicated by activation of the triac and closing of the circuit.
  • Troubleshooting and reassembling the device.

Connect the water heater to protect against leaks, overloads, short circuits should be through a RCD or an automatic circuit breaker.

Knocking out a boiler safety disconnect device occurs for several reasons. The breakage can be found by yourself. Since the RCD is not equipped with a circuit and is a complicated device, it is easier to replace than to repair.

| Denial of responsibility | Contacts |RSS