DIY water heater repair

Recommendation points

• Typical causes of malfunctions
• Dismantling the water heater
• Electrical and thermostat repair
• Tank cleaning
• Completion of repair and assembly

Most water heaters have a standard device and must be repaired at home with your own hands, using a tool that is always available from a home craftsman. We have prepared a detailed guide for you to help you learn how to maintain and repair water heaters.

Typical causes of malfunctions

The moment at which the water heater fails is always the most inappropriate. However, even at home, most faults are easily remedied. This is true both for the simplest tanks and for heaters with double tanks and electronic control.

Most often, the heating element fails. The tank does not show signs of life, the indicator light does not turn on and, although the thermostat characteristically clicks, giving the command to turn on, the water remains cold. In this situation, the most difficult thing for you will be to find a heating element and a repair kit suitable for the boiler. Symptoms are not always unambiguous: sometimes the indicator light itself can fail when the heating element is fully working, so watch the temperature.

Leakage of the tank is also a common defect. As a rule, this is due to the unsuitability of the sealing collar, which covers the technical neck of the boiler. The malfunction is accompanied by a very small seepage of water, which often goes unnoticed by the owner, and a crust of lime and oxides gradually builds up inside the technical compartment. If it did not come to the destruction of the tank walls, the problem is solved by ordinary cleaning and repacking the neck with the replacement of the magnesium anode.

The most dangerous is the failure of the thermostat, because of which the water heater simply refuses to turn on or, worse, does not turn off when the set temperature is reached. In the absence of a pressure relief valve, the latter can lead to very, very disastrous consequences..

Dismantling the water heater

It is recommended to follow one simple rule: if the boiler has the slightest signs of malfunction, it is better to carry out a complete disassembly and comprehensive revision. To do this, you need to drain the water through the cold water supply pipe by opening the “hot” tap for air suction. With the correct hydraulic piping of the boiler, this possibility is always provided. Unpack the connection fittings and loosen the anchoring nuts to lift the tank up and off the wall.

Classically shaped water heaters are served from the bottom. First you need to remove the protective cover of the control unit by unscrewing a few screws and unfastening the latches. The task is quite subtle: not only can some fastening screws be hidden under stickers, a regulator knob or a nameplate, but also fragile clips are located far from obvious places.

There is an electrical wiring inside the unit: the red and blue wire, terminated with terminals, are removed from the heating element contacts, the yellow-green is disconnected by twisting the grounding nut onto the case. Following them, we disconnect the wires of the thermostat and the temperature controller, remove the heat conductor, which is sometimes made in the form of an ordinary single-wire copper wire.

Having divided the tank and the electrical part, we twist the technical flange fastening nuts. After removing them, you need to pull up and tear off the flange from the neck, it can stick to it thoroughly. In this case, the tank must be in an inverted position so that the remaining water does not flow out onto the floor..

When the flange together with the devices attached to it is removed, you can clearly assess the quality of tap water. Scrape off the main part of the dirt from the functional elements directly into the tank and set aside for the time being, we will return to the heating element and the anode a little later.

In stylish and modern tanks, the lower part of the body acts as a protective casing. Display and control panels, built-in thermometer are auxiliary equipment that is not directly related to operation; in case of failure, they change modularly.

Electrical and thermostat repair

Most electrical faults can be diagnosed as soon as the protective cover is unfastened. With a multimeter in the voltage measurement mode, we check the presence of potential at the terminals of the heating element, making sure that the connection diagram is working correctly. There is no water in the tank, so we apply voltage to the heating element for no more than 3-5 seconds. So, if there is voltage, but there is no heating, the heating element burned out, if there is no voltage when the thermostat is on, the electrical part is faulty. Following from the heating element to the power wire, look for the cherished 230 V at key switching points and identify the faulty part of the circuit.

Let’s start with the heating element: in the resistance measurement mode, we touch the contact plates with the probes. Resistance, depending on the power, should be in the range of 15-60 ohms. Please also note that there are combined heating elements with several coils and, accordingly, with several pairs of leads..

If the item is found suitable, the problem is most likely in the control thermostat. This device has a forced ON button. If, when you press it, voltage is applied to the heating element or the button stubbornly refuses to be pressed, the malfunction lies here. The thermostat can be removed, snapped off the case and try to restore the jammed mechanism, the principle of which is quite obvious. But these devices are cheap and it’s easier to include a new part in a repair kit..

All places with a detachable electrical contact must be cleaned of traces of corrosion, tighten the connection terminals with pliers and restore the melted insulation in places.

Tank cleaning

Boiler repairs involve a good portion of the dirty work. Filling and draining water through the neck several times, you need to remove all large debris. Then assess how bad the tank is, whether there are traces of deep corrosion.

The tank must not be cleaned mechanically, especially if it is covered with glass enamel. For these purposes, a wide range of gentle chemistry is intended, which can have an acid-etching and alkaline principle of removing deposits. For coated tanks, the difference is not fundamental, but for unprotected stainless steel, means with a high Ph will be preferable.

To speed up the process, you can use a plastic bristle brush. After cleaning the tank, visually assess the condition of the welds, just to have an idea of ​​how long the boiler can still last. Do not forget to also remove all deposits and rust from the neck, otherwise the flange will leak after packing..

Completion of repair and assembly

Actually, this is where the repair ends: having identified the faulty parts, you need to purchase a replacement and, in most cases, install a new sealing lip. Unscrew the rest of the magnesium anode and screw in a new one. The heating element, if still working, must be scaled off and returned to its place, or replaced.

Heating elements are usually fastened under a wide pressure washer or through a wire through a sealing collet.

The cuff is pulled over the neck, followed by the installation of the flange with all the reinstalled elements. We tighten the nuts through one or crosswise, achieving the most tight and even pressure on all sides.

You just have to reconnect the electrical contacts and check the boiler’s performance before returning it to its place. It is better to do this by measuring the current with a short-term turn-on, or by assembling the circuit by weight before packing the flange, immersing the heating element in a bucket of water.