Why thermos does not hold the temperature and how to fix it?

Why thermos does not hold the temperature and how to fix it?

If the thermos stopped holding heat, then this indicates certain problems in his work. When this breakdown touches a new thermos, it rather indicates a factory marriage. But if the device does not save heat after a certain time of use, the breakage occurred already during operation. Depending on the nature of the malfunction, you can try to correct the situation with various methods.

Main reasons

There are three main reasons for the thermos to stop keeping the temperature inside. The first problem concerns dishes having a glass flask. The fact is that silver coating is necessarily present in such devices. It is located on the surface of the inner cylinder. This reason refers to new thermos, since such a malfunction is characteristic of the factory marriage.

And the problem may be in failures with a plug and in the absence of a vacuum. These faults can be both factory and acquired already during operation. That is why they should be understood in more detail.

Internal and external flask

It is no secret that thermos – This is a very fragile design, Therefore, it should be as neat as much as possible. So, even with minor mechanical damages on the surface of both an internal and external cylinder, deformations and cracks may form. They will become in the future the reason for the fact that the thermos does not hold the temperature.

In each thermos there are two bottoms: external and internal. A thin copper tube is located on the inner, through which air is pumped out at the factory. If for some reason in this process fails, then, regardless of the material of the dishes (glass, steel, stainless steel), it will stop saving heat.

Check such a breakdown is very simple. Enough in glass or iron thermos pour hot water. If the surface of the device itself begins to heat up, and boiling water is slowly cooling, then the problem lies in the absence of a vacuum.


The reason that the thermos poorly retains the temperature, it may become a fault of both corks and an outer cover (often used instead of a glass). The breakdown of the latter may occur in mechanical damage, for example, when falling. Cracks and deformations may form on its surface.

If the inner cork is too twisted too much, then after a while it is also possible that it is deformed, or cracks are formed on it. This applies not only to glass thermoses, but also metal.

What to do?

If the thermos stopped saving the temperature, you should not despair and hurry to throw it out. Some breakdowns can easily repair. So, if it turned out that the reason for the defect is in the traffic jam, you can choose a suitable. Buy old thermos with hands. Often people give them in purely symbolic cost.

And you can also try to make a plug more sealed. To do this, you will need to use a special sealing tape or isolate. Resorting to such a way it is important to remember that the repair will not be long-term.

If the thermos stops working in the right mode Due to the lack of vacuum, then this breakdown It is unlikely that you can repair yourself. But with such a problem, you can contact the masters engaged in the repair of refrigerators. There, a specialist using special equipment will be able to roll out excess air through the copper tube, and its end reliably sends.

Important moment! To return the thermos for the previous performance, should not be resorted to the use of superclaud and other similar compositions (for cracking cracks). They are potentially dangerous chemicals.

Even if the thermos failed to repair, still one should not despair. You can use it for products that do not require heat conservation, for example, for cold tea or compote.

Prevention measures

As already mentioned, the problem of the conservation of heat can be encountered both under the new, and with the thermos already in operation. In order not to purchase a thermos with a breakdown, you need to carefully check it in the purchase process. Check consists of several stages.

  1. The thermos must be carefully examined on all sides. Special attention should be paid to the density of adjustment of the plug and the lid to the main case. When twisting and spinning, it should not publish any extraneous sounds.

  2. Oddly enough, thermos need to smell. Poor-quality dishes will make an unpleasant smell.

  3. The material from which the dishes are made visually and to the touch should be durable. From buying down-quality goods it is best to refuse.

  4. It is noteworthy that thermoses with a flack of tempered glass rightfully considered the highest quality and durable. But in the process of choosing such an appliance it is very important to pay attention to the silver coating, which in this case is necessarily present. If it is low-quality, then such a thermos will initially not keep the temperature properly.

  5. If there is such an opportunity, You can pour a little hot water to the thermos and see how the device can cope with the main task (saving the temperature).

Choose a good and high-quality thermos not enough. Since the design of such a type of dishes is rather fragile, then during operation it is necessary to treat it as gently.

Before filling the container with hot liquid, it must be prepared. Pre-training process is simple:

  • In the container you need to pour a small amount of hot water and leave for 5-10 minutes+

  • Then the water must be gently shake and pour+

  • Now you can fill the main fluid.

This procedure is necessary to warm the seams that are available in each thermos. As well as pre-warming the surface will save from a sharp temperature drop, which also addicted to the device.

During operation, it is necessary to minimize any mechanical damage not only for glass, but also metallic dishes. Of course, iron thermos will not break, but cracks may form in the seams. Even minor deformation can cause a violation of vacuum. With such damage, the operation of the thermos will be finally broken.

Important moment! It is extremely recommended to acquire a thermos from hand or in dubious places (subway, small kiosks). In such outlets, the chance to purchase goods of poor quality increases several times.

Nobody insured from the factory marriage. But if you follow the instructions for the choice, you can buy a completely high-quality thermos, which properly serves more than one year. In the process of purchase, it is important to navigate both the appearance and the manufacturer. Better to abandon cheap options for dubious production. So that the thermos served for a long time, should not save on it.

Even if lucky to acquire good quality goods, it is important to treat it in the process of operation. You can not drop and apply any mechanical damage to dishes. Cork need to be swirling in moderation strongly. Excessive twisting may result in subsequent deformation. If you follow all the rules and recommendations, then the thermos do not have to repair.

Repair features are also presented in the following video.

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