The thermostat for a water heater is a fairly important part. It is he who is responsible for maintaining a certain temperature at a constant level. The thermostat for the water heater is capable of slowly adjusting the temperature, and it is also equipped with a device that protects it from cooling and overheating. When the need arises, he turns on and off the type, that is, the heating element.
This device allows the user to set a specific operating mode and also maintains the temperature level in automatic mode. If the water temperature decreases, it turns on the heating element, due to which the temperature rises to a certain specified level.
The thermostat for a water heater has a certain operating principle. It is worth saying that it is similar for all types of water heaters. On the screw with which each thermostat is equipped, a certain required water temperature is set. When the swelling valve is tightened, hot and cold water begins to flow into the mixer system, and then the adjustment process begins. The temperature of the water is measured in the chamber, after which the warm water is mixed with cold water required proportions. When supplying water for mixing, hot water has priority, so it will be supplied until its temperature is higher than the set value. After this, the process of mixing it with cold water will begin. Thanks to this fact, it can be explained that the thermostat for the water heater does not respond so quickly. However, the user usually does not experience any particular inconvenience.
If the thermostat for the water heater is installed in a system where there is no circulation warm water, then it is possible to hit cold water into the incoming stream initial stage. In systems where there is circulation of warm water, the thermostat adjusts the required temperature in an instant.
Storage and flow units are usually equipped with different heating elements. Typically, heating elements in flow-through models have higher power. That is why the choice should be made only after you have decided on its purpose.
An electric thermostat may have normally closed or normally open bakelite. Often owners of water heaters decide to do-it-yourself repair. The thermostat for the water heater "Ariston" and other companies is an electrical part, so it is worth remembering that different warranties are given for the tank itself and for it. If you need to replace any element of the water heater or have it repaired, you should contact service center or directly to the manufacturer, where you can find out whether it is subject to warranty repair. It is important that the appropriate thermostat model is available.
If you are wondering where you can purchase this device when yours is out of order, it is worth noting that most companies involved in the production of such equipment provide delivery throughout the country. For example, you can order a thermostat for a Thermex water heater at home. It is easy to replace it yourself using simple recommendations.
Problems in the field of housing and communal services in our country, unfortunately, are far from uncommon. But some of them, for example, the lack hot water, you can solve it on your own. To do this, you need to purchase and install a water heater. Enjoying a shower at a comfortable temperature, even when others do not have hot water, will allow you to tankless water heater with thermostat.
Let's look at what a water heater consists of.
Main elements of a water heater
- External body. It can be plastic, metal, or its design can combine elements of both types.
- Internal tank. Usually made of stainless steel.
- Thermostat (thermostat)
- Thermal electric heater (heating element)
Let's look at the next two elements of the water heater in more detail.
Thermostat
So, what kind of beast is this, a thermostat for a water heater, and what is it for? It's simple: the thermostat is designed to maintain a certain water temperature by turning it on and off heating element(tena). Also, if a malfunction occurs in the heating element, the thermostat (or thermostat) will turn it off in emergency procedure(thermal protection).
There are 3 types of thermostats.
Types of thermostats
- Rod thermostat for water heater. It is inserted into a special tube located on the body of the water heater, 25-45 cm long. Rod thermostats for Thermex water heaters are most often used.
- Capillary thermostat for water heater. It looks like a tube containing liquid. It changes its volume depending on the temperature in the heater tank. At a certain heating temperature, the liquid exerts pressure on the membrane associated with the electrical contacts.
- Electronic thermostat for water heater. The thermal resistance that is part of it reacts when the temperature of the liquid changes. Typically, two such devices are installed in a water heater. One of them performs the temperature control function, and the other performs the protection function (emergency shutdown).
Choose a thermostat for a certain model water heater can be based on geometric dimensions heating element, the magnitude of its power, as well as the volume of the water heater tank.
Thermostats for Ariston water heaters are electromechanical and electronic. The operating principle of the former is based on the properties of bimetals, the functioning of the latter is carried out using a high-precision sensor included in their composition.
Depending on the capabilities, they can be divided into simple, programmable and dual-zone. Based on the installation method, models are divided into overhead and mortise.
If the thermostat is faulty
As a rule, repairing a water heater thermostat involves replacing it with a new one. How to detect a malfunction of the thermostat? This can occur if the heating element does not turn on when voltage is applied, or if the control thermostat is triggered. To check the functionality of the thermostat, it must be removed from the water heater, then put to measure resistance (Ohm). Set the adjustment handle to the maximum position and measure the resistance at the thermostat contacts (input/output). If the tester does not show any reaction, this indicates a faulty element. It cannot be repaired, and to replace it you will need to buy a thermostat for a Thermex, Ariston or other brand of water heater, the same as the water heater.
If the control thermostat is triggered, we determine the malfunction as follows: you need to put the removed thermostat in the minimum position and install test leads device on the contacts. Then use a lighter to heat the thermostat rod or bulb. If it works properly, then you will observe the following picture: the thermal relay will work and open the circuit, the resistance at the contacts will tend to infinity, that is, as when the probes of the device are moved apart. If this does not happen, then the thermostat is faulty and the thermostat needs to be replaced. To do this, you need to choose the right element of the water heater.
How to choose the right thermostat
It is advisable to buy a replacement thermostat for the water heater of the same model that was originally installed. But if you don’t find exactly the same model on sale, then when choosing, you need to consider the following:
- type of thermostat, installation dimensions and mounting method;
- the amount of current for which the thermostat is designed;
- the functions it performs (temperature regulation, protective function or both at the same time).
Thermal electric heater (heating element)
A thermal electric heater (TEH) is a heating element; its power determines how quickly the water in the tank will heat up.
Tens come in two types.
Types of heating elements
Tubular heating element. This type of heating element is the most common; it also includes heating elements for water heaters with a thermostat. This ten looks like metal tube(it can have any shape), inside which there is a conductor with a high electrical resistance(due to it, the tube is heated, which in turn transfers heat to the water). Insulation is provided by dielectric sand, which fills the space between the wall of the metal tube and the conductor. The main problem when operating such heating elements is scale, which significantly reduces heat transfer.
The advantages of this design are less heat loss due to scale and greater electrical safety.
Dry heating element. It differs from the one described above in that it is placed in a special flask for protection. The space in the flask is filled with either quartz sand or special oil. Thus, it turns out that the design is a ceramic heating element.
How to choose a thermal electric heater (heating element)
A heater for a water heater with a thermostat is very convenient for use in everyday life, for example, at home or in the country, for heating water in various containers. The thermostat will allow you to control the temperature to which the water is heated.
When purchasing a heating element, you need to pay attention to the following points:
- What exactly is the water heater intended for?
- Supply voltage;
- Power consumption;
- What water temperature is required;
- Heat transfer conditions;
- Character of heating;
- Type of thermostat (regular or with thermal protection).
The thermostat for a water heater is often called a thermostat. Remember this so as not to get confused in concepts and not fall into a stupor when you discuss the issue of choosing a boiler and thermostat for a water heater.
- 1 Features and types
- 2 Operating principle
- 3 Fault detection
- 4 Selecting a thermostat
Features and types
In fact, the thermostat performs a fairly simple function from a theoretical point of view, but a complex one from a practical point of view. Namely, it supports optimal performance temperature, turning on and off the operation of another component of the water heater - the heating element.
In the event that problems arise with the heating element, the heating element fails, the thermostat performs another function - protective. It’s called thermal protection, that is, emergency shutdown of the boiler.
Now regarding the types of thermostats. There are three in total.
- Rod. It is inserted into a tube, which is located on the body and has a length of about 25-50 centimeters;
- Capillary. They are also made in the form of a tube, inside of which there is liquid. It changes its volume depending on the temperature at one time or another inside the tank. When the desired or specified temperature regime, the liquid acts on the membrane, which, in turn, is connected to the contacts;
- Electronic. The boilers include special thermal resistances that react when the temperature of the water inside the device changes. As a rule, it has two electronic regulators at once. The first is responsible for temperature, and the second is for protection. Of course, such devices are the most expensive, but also the most effective.
When choosing a water heater with one or another thermostat, take into account the fact that you may need to replace components if they fail. This process doesn't have to be very expensive. Whatever one may say, thermostats can be called consumables, exactly like heating elements, that is, heating elements.
Principle of operation
If we take into account the main aspects of the operation of thermostats, then we can briefly talk about it as follows.
- The required temperature is set on the boiler. For this purpose, there may be provided on the body various designs— switches, buttons, levers;
- When the mode is set, the thermostat measures what temperature the water is at the moment, and then turns on the heating element if necessary;
- As soon as the temperature reaches a given level, the circuit breaks, as a result of which the heating element stops working, that is, heating the water in the container;
- When the water cools, and this necessarily happens, the thermostat detects the drop in temperature, closes the circuit again, after which heating continues.
Fault detection
Let us note right away that such an element as a thermostat for a water heater cannot be repaired, that is, if it fails, it should be immediately replaced with a new component. But first you need to determine that the old device is faulty.
If you notice that the heating element does not work when the voltage is turned on, it is quite possible that the regulator is broken. To check its performance, you should remove it from the tank and measure the resistance, which is calculated in Ohms using a special device. Set the adjustment knob to maximum and check the resistance at the contacts. If the tester remains stationary, then the component has failed. Buying a new thermostat is not at all difficult, but there are some nuances.
Selecting a thermostat
The best option would be to purchase the same element that has failed. By contacting the store where you purchased the heater, there is a good chance you will find the required component. However, sometimes it is difficult to find an identical temperature controller, and therefore you will need to find an analogue. To do this, pay attention to:
- Type of regulator, its dimensions, as well as methods of fastening in the boiler;
- Functions performed, that is, adjustment, protection, or two functions at once;
- The current that your old thermostat was designed to handle.
It is obvious that thermostats play an important role in the proper functioning of the water heater. It’s not difficult to replace it even yourself, and it’s not difficult to find the necessary thermostat on the market. The main thing is to know the characteristics of the failed element in order to select a new one by analogy. But this is in case it was not possible to purchase the same thermostat, which does not happen very often.
2016-12-14 Evgeniy Fomenko
Method for repairing a thermostat
The first stage of repair is to disconnect the water heater from the electrical network, then drain the water, and remove the heating element from the water heater. Remove the thermostat from the heating element by carefully pulling it out. Drill out the copper rivets holding the body together, disconnect the body from the rod, this must be done carefully so as not to damage anything.
There are two methods for cleaning bimetallic plates: if the contamination (oxidation) is not very strong, try cleaning it with a cloth soaked in alcohol, inserting a piece between the plates and wiping; if such cleaning does not produce results, clean the plates with the finest grit sandpaper. It’s even better if it’s already used, so as not to break contacts.
The breaker contact (rocker) may have stuck to the housing. To fix this problem, disconnect the contacts and clean the area. The break contact should return to the upper position automatically.
If this does not happen, remove the “rocker” from the device, clean it with fine abrasive sandpaper, clean the place where it is installed (perhaps melted plastic has stuck there), and install it in its original place. If the “rocker” still does not return to its original place, glue a piece of insulating tape under it, selecting such a thickness so that the contact plate returns to the upper position.
Insert the rod back, tighten the housing using self-tapping screws, and insert it back into the heating element.
In addition to those described above, there are the following possible malfunctions thermostat, which can only be eliminated by replacing it:
- The copper tube has worn out.
- Electronics malfunction.
- Malfunction resulting from voltage drops.
If you find that your device has stopped working, there are ways to check the problem yourself. To check the operation of the thermostat for the water heater, you will need to remove the thermostat and set it in resistance change mode. We set the maximum possible temperature, measure the resistance in the input and output contacts of the device.
If the device shows infinite resistance, you can safely conclude that it is faulty. And if there is resistance, then turn the regulator to the highest small value and reconnect the contact tester. Next, using a lighter or candle, we heat the tube of the device; if the device is working properly, the relay will operate, which closes the circuit, and the resistance indicator will increase. If this does not happen, the device is faulty.
If you are unable to repair your thermostat, you should follow these recommendations to find a suitable device. The most the right decision will be purchasing the same device, from the same manufacturer.
However, if you haven’t found it, when choosing, pay attention to its dimensions, the method of attachment to the water heater, the number of functions performed (only temperature control, or also protective), and the voltage for which it is designed. When you go shopping for a new one, don't forget to take technical certificate to a boiler or a faulty appliance.
Video about the thermostat design:
