The Presscon ELC system was developed to link two stand-alone heating systems. With the Presscon ELC system, it is possible to move heat between different storage tanks that are coupled together. ELC stands for Equal Level Control and is a control function integrated into the Presscon Expansion system.
A fixed supply is created using a computer-controlled supply pump running at a fixed frequency, with valves and pressure control mounted on it. The return pump, connected to the Presscon ELC System, is started using a frequency controller and will run at a frequency determined by the ELC System. The return pump is frequency controlled and can therefore run slower or faster than the supply pump. This way, the mass of water in each tank is controlled. Using valves, the ELC System can also control the direction of the water.
If the pressure of the water column in the control tank is 15 mbar lower than in reference tank, the analog output sends out 4 mA. The return pump then runs slowly.
If the pressure of the water column in the control tank is 20 mbar higher than in the reference tank, the analog output sends out 20 mA. The return pump then runs at a maximum of 50Hz.
The system regulates purely on pressure difference and not on water level. It is therefore possible that the water level in tank X is higher than in tank Y. The greater the temperature difference between tank X and Y, the greater the level difference.