Pressure drop in a piping system is a result of resistance to flow. Total pressure drop is a critical issue for selecting pump size. The pressure drop of a radiator depends on water flow rate and radiator size. It is significant for bigger size radiators.

The pressure drop calculation of panel radiators, as a part of total pressure drop of the system, is given below with an example.
Pressure loss of a radiator can be found using the pressure drop graphs of radiators with and without valve insert (please note that for radiators with valve insert we refer in our documentation to the supplier of the valve insert Heimeier).

Pressure drop of a radiator without valve insert

Example: What is the pressure drop on a radiator of size 600/22/1000?

Qn=1672 watt = 1441 kcal/h for a 600/22/1000 radiator @ 75/65/20 nominal temperatures
Water flow rate = Qn/(water inlet temperature-water outlet temperature)
Water flow rate = 1441 / (75-65)
Water flow rate = 144.1 kg/h
Having known water flow rate 144.1, the pressure drop is read on the y-axis of graph as 0.002 bars (using the Type 22 line).

Pressure drop chart of a radiator with insert valve