Reasons why the radiator does not heat even after de-airing

With the beginning of the heating season, it may turn out that some radiators do not warm up at all, even if they are not aired. The reason is that the coolant circulates along a path of less resistance. If there are miscalculations when laying pipes to the battery, it simply flows before the radiator sections.

Bypass location problems

If the bypass is placed close to the riser or the battery has recently been moved further, then most likely it will not heat. In such situations, the coolant simply circulates through the bypass.


The problem is solved by moving the bypass closer to the radiator, or replacing its tee with a two-way or three-way valve. The first option is preferable. When installing the tap on the bypass, there is a possibility of forgetting to switch it when the flow to the batteries is blocked, as a result of which the entire riser will be blocked.

Problems with lack of heating in distant sections of the battery

In a system with a side connection, it is often just the first sections of the radiator that are heated, through which the entire flow volume passes, and the coolant is in the outer fins, so they remain cold.This problem is especially relevant for long batteries.

This can be solved by connecting pipes diagonally. This method is the best solution, but not always possible for technical reasons.

A flow extender also helps in this situation. It is a tube laid inside the battery. The coolant flows through it to the last section and goes through the entire battery to the exit. The method is less effective due to the narrowing of the flow, but does not require moving the pipes.

Watch the video