Hydratec Inc.

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Standalone HydraCALC (Location)

Button: Calculation Summary Function: Calculation Results Error Type: None

Description:

The calculation results shows a pressure requirement which does not show up in the Final Calculation printout

In the example below, 104.344 psi is nowhere in the Calculation Sheets of the printout.


Solutions:

Cause:

This is not an error. 

Due to having a pump, the calc results window shows the pressure and flow requirement at the source.
Solution:

In this calculation the source point SRCE has available pressure of 115.768 psi.  

The safety margin is 11.42 psi

The system demand at the pump outlet PO is 104.344 psi

115.768 - 11.42 = 104.344

The value 104.344 is nowhere in the Final Calculation printout.



FYI, the Water Supply Graph sheet will show the pressure demand at D2.  This is the pressure at the reference point PO




In the calculation sheets, the Safety Margin is figured by comparing the System Demand Pressure (120.035 psi) to the Continuation Pressure (131.459 psi).  The difference is your safety margin (11.424 psi).

131.459 - 11.424 = 120.035


System Demand Pressure is what your sprinkler system requires

Continuation Pressure is what the source is providing.


You can find more information on the calculation printout by going to this folder;

"C:\HES\HydraCALC\VER50\Docs\"

And reviewing this document; 

"Understanding the HydraCALC Printout.pdf"
Updated: Oct. 16, 2026, 4:51 p.m. Created: Oct. 16, 2026, 4:28 p.m.