User Guide PFM 1000
14 | VU.E2.G1.02 © Danfoss | 2019.02
Heating Engineering
Calculations
Heating engineering calculations allow and make easier solutions of partial tasks and calculations in
balancing hydraulic systems.
There are the following four calculations in the PFM 1000 application:
1. Preset calculation - calculates the valve preset for the flow requested in the current branch.
2. Pressure loss calculation - calculates the pressure loss on the valve for the requested flow and
preset.
3. Available pressure calculation - The “available pressure” is understood to be the minimum pressure
in the branch after the requested flow is attained for the given preset.
4. Valve authority calculation - The valve authority is the ratio between the pressure drop on the
fully opened control valve and the pressure in the whole branch in percent. This quantity helps in
dimensioning the valve and evaluating whether the given valve is suitable for the branch. For the
optimal use of the system regulation, this should be in the range of 50 up to 100%. When this value is
less than 50%, the valve is not dimensioned properly.
Press the Calculations in the application’s main menu. Select the requested valve and its preset in the
respective selection fields of the Calculations introductory screen.
Preset Calculation
It calculates the valve preset in the current branch for the requested flow.
Enter the requested flow in the first Preset calculation screen and confirm the entry with the OK
button. Confirm with the actual flow with Save current measured flow button in the next screen.
Close fully the control valve in the next screen. Confirm the measured pressure value with the Save
current disposal pressure button. Based on the measured values and the requested flow, the PFM
1000 application calculates the needed valve preset and displays the result in the Calculations
window in the Results section of the screen.
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