9.8.3. Radiator heating – unsatisfactory sizing of diameters<br>

### 9.8.3. Radiator heating – unsatisfactory sizing of diameters

Sizing of pipe diameters in central radiator heating and in manifold supply network of floor heating is performed according to criteria specified in “Diameter sizing options” tab. The values of these criteria depend on the location of the pipe-run, which is specified in the graphical editor. For practical reasons they are different, for instance, for radiator circuit pipes and risers or distribution network. A pipe-run with a defined flow rate will have a 20-mm diameter as a radiator circuit pipe, but in case of a segment of an apartment system, where lower friction R is set, the required diameter is 25 mm. If a smaller diameter is preferred (e.g. because of the availability or cost of couplings and fittings), and the user does not wish to increase Rmax for the entire apartment system, selected pipe-runs with their location indicated as ‘apartment’ may have it changed to ‘circuit pipe’, and the calculations with resizing of diameters may be repeated.

Sometimes complete inability to size diameter of a pipe-run is indicated. This may particularly happen in case of using a default type of pipes, when that type has a relatively narrow range of available diameters. If in the catalogue, from which the default type was selected (e.g. coiled pipes), is a similar type with a wider range of diameters (e.g. cut length pipes), then that type is usually designated as the ‘successor’ and then a pipe of such type can be selected. This requires that the “Skip to pipe successors” option is checked in the diameter sizing options tab.