Hydronic heating system uses ONE line for supply and return?

Question

Have just bought a house in which we've inherited a hydronic system - so just beginning diagnosis and diagramming, etc.

It seems that radiators use only one line for both supply and return; presumably valves in each radiator regulate flow to that radiator? Apart for a need for balancing the whole system - some rooms are too hot, others cold - it basically works.

Longer-term vision for system is to break it up into 'n' zones; individual valves, and I imagine, dedicated return line. At this point, house has only two zones, so much work to be done in warm weather!

Does this sound like a crazy setup? An ad-hoc kind of installation?

Answer 1

You have a One Pipe System and it looks and works like this

one pipe

Suggest to Read the article, it nicely explains the details.

The main drawback is there is a temperature drop at each radiator feeding back in the single line thus reducing overall heat supply. Thankfully each radiator has a thermostatic valve for individual control.