2.4.7. Specifying calculation options, diagnostics and running calculations<br>

### 2.4.7. Specifying calculation options, diagnostics and running calculations

Calculations are launched by pressing the F10 function key or by clicking on the calculator button. Firs a diagnostic run is done in which possible errors that make calculations impossible can be detected or after which a list of warnings and hints is displayed. If the messages displayed do not indicate the occurrence of any errors in data, calculations may be continued. Click on the calculator and “Next” button in the message list window. Now the calculation options should be specified.

If errors occur, or if you want to remove the causes of warnings, you have to go back to editing by clicking on the “Back” button. After reverting to the editor the list of errors and warnings is displayed in a separate window. After clicking on a component in the list the object to which the message applies is marked in the drawing, which facilitates finding and correcting the right data. Some error types, e.g. those that apply to the interpretation of connections, cannot be assigned to the component that caused the error (as such component cannot be indicated explicitly.) and can, for instance, be assigned to a source in the area where the error has occurred.

In case of messages that occur many times (for many similar components) the correcting of the data usually consists in entering (or changing) the same data for all these components. In such case it is best to click the right mouse button on any of the recurrent messages and selecting “Mark all components where this error occurred” from the pop-up menu. Then you will be able to enter into the data table the value, which will be entered or modified for all components with the given error.

If no messages are displayed after the diagnostic run, then after pressing the F10 key the tabs with the list of calculation options and results are displayed. On the left-hand side of the screen is a list of grouped calculation options. Their detailed description is given in further sections of this manual.

The first item (in the case of a system with no floor heating) in the list provides diameter sizing options. For every family of pipes (catalogue or a folder in that catalogue) used in the project the following data can be specified: minimum sized diameter, maximum friction R and – indirectly, using a multiplier for the value specified in the catalogue – maximum velocity of medium in pipe-runs, separately for radiator circuit pipes, apartment system (between circuit pipes and riser), risers and distribution network. If the project was calculated before and there is a need to size pipe diameters again, check the “Resize diameters” box. A table with diameters available for the given family of pipes and maximum velocities assigned to them can be viewed by clicking on the button beside the name of the family. Moreover, one or more diameters can be indicated as unavailable for sizing.

The next item in the options list contains options of flow calculations (system balancing), including the specification of minimum pressure drops across each terminal unit and its control fittings (providing required hydraulic stability of the system) and across control valves in the system. Here you can also specify or indicate for calculating (by entering “?”) available pressure in each source (this is equivalent to editing this value in the data table of the source in the graphical editor). If there are pumps entered as graphical components on pipe-runs, other than in mixing systems, then they also form a driving force for medium circulation in the system and it may occur that the calculated available pressure for the source is equal to zero. Pump head is specified in pump data tables in the graphical editor. To recalculate the pump head the “Resize pumps on pipe-runs” box must be checked and the “Retain specified head of pumps on pipe-runs” box must be unchecked.

The subsequent item contains heat calculation – radiator sizing options. Here you specify for each radiator type used in the project whether they are to be selected from stock or from the entire catalogue, whether dimension restrictions are to be taken into account, whether allowance for output is to be taken into account when a thermostatic valve is used. The percentage of heat utilisation from radiator circuit pipes and risers can be set collectively for all types. Here you can also launch resizing of radiators in a system calculated before and specify whether the specified radiator sizes are to be retained. Adjustment of radiator operating parameters may be done for both sized and specified radiators by increasing or reducing the flow rate across radiator, which induces lower or higher temperature drop of the medium in the radiator.

The last item in the list enables specifying the rules of editing results, first of all indicating whether a bill of materials and a list of components on pipe-runs and terminal units are to be created. Creating these lists is time- and computer power-consuming (the project is displayed noticeably slower after reverting to the editor), and therefore their creation is not recommended if there is no need for them. They are just a source of information that facilitates detailed checking and analysis of results.

Clicking on the “Results” tab launches the calculation process. Upon completing the calculations, their results are displayed in many tables the titles of which are displayed on the left-hand side of the screen in the form of a list. To display individual tables of results in the upper right-hand window click on the selected item in the list. Errors, warnings and hints may also be indicated during calculations. If errors occur, the results cannot be treated as complete, even though some values may appear in tables or in the drawing, e.g. pipe diameters, velocities of medium, etc.

Calculations cover all sheets of the project, except for those designated as not being subject to calculations.