Good day, dear guests!
Rarely, but one has to see situations when the heating system is installed in such a way that there is a possibility of the circulation pump to the so-called - "closed valve", i.e. a situation is possible when all circuits for the circulation of the coolant will be closed.
As an example, this happens if all circuits of the heating system are simultaneously closed by automatic thermostats on each radiator, and a pump operating at full capacity, it is impossible to ensure circulation coolant.
If the pump is a frequency pump ("with brains"), which in automatic mode allows you to adjust the speed of rotation of the impeller and, as a result, the intensity of circulation, then this is for he is not afraid, since when the resistance of the heating system increases, he himself reduces his performance and can be in the waiting mode for opening any of thermal head.
If the pump is asynchronous (old model), this mode is unacceptable for it. Such a pump is indiscernible to the resistance of the system, and when a certain critical threshold is reached, the load increases in the pump on the mechanical part, the current increases, the pressure rises sharply, followed by overheating of the unit, and as a result - failure.
How to fix the situation
1. The easiest option - choose a room to which you do not impose high temperature requirements (such a room will always be warm) and remove from the radiator of this room - thermostatso that the pump always has at least one free circuit and does not work "into the wall".
2. The second option is to install a bypass valve. Such a valve serves to ensure a constant flow, where there is a possibility of completely blocking the same flow in the heating system. The design of the valve is simple and the device works as follows: upon reaching a certain pressure in the system - the spring is pressed, ensuring the opening of the valve, respectively, the stroke coolant.
Such a valve is regulated manually, and by adjusting it to a certain pressure in the system, you will be able to automatically unload the system when the pump is operating on the "closed valve".
The bypass valve is always installed after the circulation pump, but before the first radiator, thus it works as an automatic bypass - bypassing the supply and return lines.
I would be glad if the article helped you. Thanks for attention!
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