Variomat (pump-controlled)In Variomat pressurisation units, the pressure is controlled by the use of a pumps in the hydraulic system.
- If the set pressure is exceeded, the overflow valve opens and causes water to flow from the system into the expansion tank. The water content in the tank rises and the pressure in the system falls.
- If the pressure is below the set pressure, the pump switches on and delivers water from the expansion vessel to the system, the water content in the vessel falls, the pressure in the system increases.
With the Variomat, degassing is part of the service scope: A time control system is used to direct a partial flow from the system into the depressurised expansion vessel, where it is depressurised. Consequently,at a slight positive pressure, the released gases escape via a special valve.
The nominal volume of the vessels is 200–5,000 litres, with special sizes up to 10,000 litres available on request. The control unit functions as a combination device for pressurisation with 1 or 2 pumps and overflow valves (as motorized ball valves with a patented circuit for automatic hydraulic compensation).
For particularly high performance and pressures. The nominal volume of the vessels is 1,000–5,000 litres, with special sizes up to 20.000 litres available on request. An additional solenoid valve provides the minimum pressure protection. The Variomat Giga can be set up as a special system, for safety temperatures > 110 °C and > PN 16 according to EN 12953 or TRD 604 Bl. 2.