We have some problems with central heating in our multi-flat house and I would like to understand something. Some flats have old-style radiators, and almost every flat has different way to connect to central pipe.

Please, can you tell me which of these variants of radiator connection is correct one, for multi-story-flat house, so everyone would get heat and noone would be able to "disconnect" every other radiator on line.

enter image description here

There is drawing, editable in Google Drive.

First floor is bottom, fourth floor is top one in this diagram. Red rectangles are radiators, blue frames are individual flats.

In reality, best solution looks like the one in 3rd floor, but I'm not sure, if any water will get inside radiator, because of equal pressure points in input/output pipes for radiator.

Maybe there are other variants too? Could you give such and tell me why that is better.

EDIT: I have come up with best solution, from my point of view:

enter image description here

I'm not sure, if such 3-way valves exist, but that would be best solution, it doesn't block neighbours from getting heat and it balances incoming pressure, by giving away excess to neighbours. But I'm really not a plumber, I'm programmer :D

  • Post your solution as an answer rather than an edit to the question.
    – ChrisF
    Nov 1, 2012 at 12:29
  • @ChrisF My edition is just my solution, it is not answer to my question.
    – Deele
    Nov 5, 2012 at 8:07

2 Answers 2


The pipes should look like this:

enter image description here

There should be an unrestricted flow around the system.

Each radiator should be connected to both the flow (red) pipe and return (blue) pipe. The turnable value (or better still thermostatic valve) should be on the input to each radiator. There should be a simple on/off valve on the outlet which is normally set to fully open.

  • I think, this is impossible in our configuration, icoming pipe is in other corner of room, and it goes stright up, to the top floor. It is just about how we connect to the pipe, that is coming from top floor.
    – Deele
    Nov 1, 2012 at 12:26

They all look very wrong, as you are meant to have a flow and return pipe for the water that each radiator connects between.

However I can see how the way the radators are connect in one flat effects any other flat on a central heating system, as each flat will have its own boiler, unless you have some district heating system rather than central heating.

The pressure (of gas) to each flat should be regulated by the pressure regulator on the gas meter unless there is something very wrong with the way it has been installed.

  • They are water radiators, not gas. I know that they are wrong, and local plumbers says that they want to add another pipe in, from our pocket and I want to know, if what they are doing is correct.
    – Deele
    Nov 1, 2012 at 12:24

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