The temperature controller for the water heater works on the principle of a thermometer - measures the temperature. Why this is necessary and what threatens the breakdown of an element, read in our publication.
The device and principle of operation of the thermostat
How does the device function? On the control panel, you set the heating indicators. As soon as the water reaches the set parameters, the temperature sensor is triggered, sending a signal to the control module. The latter gives a command to turn off the heater.
In storage boilers, the water is constantly warm thanks to the temperature controller. As soon as the indicators decrease, the heater starts up again and continues heating. Therefore, you can get hot water at any time, without a long wait.
In modern models, the thermal relay is equipped with a shutdown button - thermal protection. When the heater overheats or heats the contents above the specified norm, the protection is triggered - and the work stops. Otherwise, the heater burns out.
Device Diagram:
There are several types of thermostat:
- Rod - obsolete type, no longer applicable. It is based on a tube that expands when the water is heated. From the extension, the TEN disconnect key is triggered.
This design was abandoned due to its inaccuracy. The part was located close to the intake of a cold stream, so it did not have time to react in time to an increase in temperature.
- Capillary. The design is the same, but in this case, the tube contains a fluid that expands and activates the heater relay. The error is 3-4 degrees.
- Electronic. The most accurate of all sensors. Equipped with protection against switching on without water.
The following regulators have been developed for the electric heater:
- Mechanical and electronic (overhead and built-in respectively). Mechanical triggered by the expansion of bimetallic plates, electronic when the sensor signal.
- Programmable and mechanical. The former require the installation of the necessary indicators, the latter are triggered by boiling or when the maximum manually set temperature is reached.
Has the boiler stopped heating or, on the contrary, is overheating water? The thermostat is checked first.
How to do it yourself
If possible, the item can be repaired or a new one installed.
How to remove the thermostat:
- Disconnect the equipment from the network.
- Shut off the water supply.
- Drain the contents of the tank. A special valve can be used for this. Why do you need a safety valve, read a separate article.
- Remove the heater. To do this, unscrew the nuts and bolts of the flange, remove it from the housing.
- The thermostat is usually located at or near the base of the heater.
- Disconnect the wiring and remove the sensor from the base.
In the case of a mechanical model, you can clean bimetal plates from oxidation. To do this, moisten a piece of cloth in alcohol, wipe the plate. If oxidation is very widespread, then clean with fine sandpaper.
This must be done carefully so as not to touch the sensor contacts.
Due to power surges, the opening contact may become stuck. To adjust, carefully detach it from the case, clean the problem area. Normally, the contact should become in the socket automatically.
How to repair a contact if it does not work:
- Remove the part from the housing completely.
- Strip its surface, as well as the seat.
- If after cleaning the contact does not turn on, put on the bottom of the insulation tape.
- Replace the stem.
- Assemble the housing.
When the regulator needs a replacement
It makes no sense to carry out repairs if:
- The copper pipe has fallen into disrepair.
- Electronics out of order.
- The element burned out during a power surge.
But how to make sure in practice that the thermal relay is malfunctioning? This can be checked with a multimeter.
- Set the multimeter to the resistance measurement mode, as shown in the picture:
- Attach the probes to the contacts of the part.
- Look at the scoreboard. With infinite resistance, the thermostat cannot be restored; a replacement is needed.
- Shows resistance? Do this: set the multimeter to the minimum value. Lighter warm the thermostat tube. If it is working, the resistance will increase and the protective relay will trip.
If you are convinced of a malfunction, it is important to choose the right product for replacement. How to do it? It is best to take the old regulator and go with him to the store to purchase an analog. Or write down the serial number that is on each product.
What to look for:
- Mounting method.
- The size.
- Voltage.
- Additional functions.
The parameters must match those indicated in the passport for the boiler.
If you are not good at repairs, then you can call the wizard to replace.
Remember the safety precautions and watch the video on the topic: