Hydraulic Separators Selection

Hydraulic Separators Selection Comments:

  1. Determine the maximum medium flow rate for the hydraulic separator. The analysis shows, that the highest medium values are observed in the boiler system, and thus all calculations must be carried out for the boiler system.
  2. Hydraulic separators selection type depending on the nominal flow rate. Select the hydraulic separator type with nominal diameter corresponding to the nearest higher value of calculated flow rate from the SP, SPP or SPD data sheet, Specifications/nominal flow rate table.
  3. Specify the device type (version, DN nominal diameter and shell diameter), see Hydraulic separator designation. Please specify if the special version (up to 150°C or supporting structure) is required when placing an order.


  1. Heat output for hydraulic separator:


  1. Nominal flow rate for hydraulic separator:


CAUTION: Total pump output in the heating circuit must be lower than the total pump output in the boiler system. The difference must be at least 10%.

Quantities and units:


PK     kW          – heat output


QK     m3/h        – nominal flow rate table


ΔTK   K              – differential temperature for medium supplied and discharged from the hydraulic separator on the boiler system side


ρ       kg/m3      – water density at max. medium temperature


cp      kJ/kg K   – water specific heat at max. medium temperature, hydraulic separator outlet

Volume and specific heat for different water temperatures

tabela wartości liczbowych ciepła

Example of Hydraulic Separators Selection


To connect the boiler circuit and the heating circuit, select the hydraulic separator based on the following data:



PK = 130 kW           boiler system heat output

T1 = 90 ºC               supply water temperature, boiler system

T2 = 70 ºC               return water temperature, boiler system




  1. Calculate nominal flow rate for hydraulic separator:


  1. Select nominal diameter and type:


SP, SPP or SPD data sheet or


Specifications / Nominal flow rate table

– nominal hydraulic separator diameter: DN65

Specifications / Type table

– hydraulic separator type: SP 65/150, SPP 65/200 or SPD 65/200


  1. Hydraulic separator designation:

SP 65/150         – hydraulic separator

SPP 65/200      – hydraulic separator with reduced port centres

SPD 65/200      – hydraulic separator with adjustable port centres


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