The boiler is working, but the radiators are not heating: why is the return line in the heating system cold?

The heating system is complex design, consisting of several elements combined into one contour and is launched into operation through a chain reaction.

But it happens that the system is failing and the water in the radiators becomes cold. This may be due to problems with the return line.

What is a return line in a heating system?

The return line is coolant, located inside the heating system. During operation it passes through all heating devices and gives them heat. Then, already cooled, the coolant returns to the cauldron again, where it is heated and a new cycle begins.

Photo 1. Heating diagram with a circulation pump and expansion tank. The arrows show the movement of the coolant.

The coolant acts as a regular water, and antifreeze. It is launched into operation either naturally (under the influence of gravity), or forcedly (using a pump).

Causes of problems with return flow in batteries of a private or apartment building

There are several reasons why the return line is not warm enough or is completely cold. Common problems include:

• insufficient pressure water in the system;
• small cross-section of pipe, through which the coolant passes;
• incorrect installation;
• airiness or pollution systems.

If a problem with a cold return line has arisen in an apartment, the first thing to pay attention to is the pressure. This is especially true for rooms on the upper floors. The fact is that the principle of operation of the return line is to quickly and continuous flow of liquid according to the system. And if her speed is dropping, then the coolant will not have time to push out the cold water and the batteries will not heat up.

Another reason for the malfunction of the return line is contamination of the heating circuit. As a rule, major cleaning systems in multi-storey buildings is not carried out oftenThe sediment that accumulates on the walls of the pipes over time prevents the passage of liquid.

The main reason for interruptions in the operation of the heating system in a private house is incorrect installation. Most often this happens when the installation is carried out without the participation of specialists. If you are not competent in this matter, it is quite easy to confuse the supply and return pipes or choose pipes of the wrong size.

In both an apartment and a private house, the problem of a malfunctioning heating system may be related to insufficient speed water supply or airinessIn a similar way, the operation of the return line is affected by contamination of the pipes.

Troubleshooting Methods. Why Cleaning Is Necessary?

To understand how exactly to solve the problem, you first need to establish its source. If the batteries have become cold due to insufficiently fast water circulation, then installing a special one will help pumpIt will regularly push water into the circuit under a certain pressure, thereby preventing the system from stopping or slowing down.

Photo 2. The marking of the Grundfos circulation pump allows you to choose the most suitable one and install it correctly.

If the reason is clogged pipes, then they simply need to be clean up. This can be done in several ways:

• using water-pulsating mixture;
• with the help of biopreparations;
• by means of pneumatic hydraulic shock.

In case of malfunction caused by improper installation of the equipment, contact a specialist. A qualified specialist will certainly understand the problem and eliminate all the problems. In addition, he will give practical advice and recommendations for the maintenance and operation of the system.

Useful video

Check out the video, which talks about one of the possible problems with the return line - battery contamination.

What problems arise in an apartment due to a cold return

A malfunction in the return line entails certain problems and troubles.

Firstly, batteries in this case do not heat up properly, or they don't work at all. Accordingly, the room itself becomes cold, which is certainly not good.

Secondly, when the functionality of the return line is disrupted, a strong temperature dissonance supply and discharge of liquid.

This leads to the accumulation of condensate on the walls of the boiler, which begins to react with the carbon dioxide released from the combustion of the fuel. The consequence of this process is the formation of acid, which corrodes the walls of the boiler, thereby destroying it.