Thermostatic pump group Regulus Thermovar LK 810

Burning causes releasing of water, among others, from the fuel in the form of steam. If the flue gas is hot enough, the steam leaves through the chimney together with flue gas. However, if the flue gas gets cooler at some spot, condensation of water vapor occurs there. The condensate contains products of burning that can be very aggressive esp. when burning wood or solid fuel and thus cause deposit formation on heat transfer surfaces and in steel boilers also fast corrosion. Blocked heat transfer surfaces increase the risk of lime formation and cause the efficiency of combustion getting worse.

Termovar LK 810 thermostatic group mixes cold water returning from a heating system (or from an accumulation tank) with hot water from a boiler. This keeps return water at the given minimum temperature (55 °C, 65 °C, 70 °C according to model) and the boiler works with better efficiency. This process also limits clogging of heat transfer surfaces and formation of aggressive condensate. The lifetime of the boiler is then substantially longer. The higher the return line temperature, the lower the risk of condensate formation. The pump group also involves a floating check valve enabling boiler cooling by gravity circulation in the event of power supply failure, and at the same time recooling of the accumulation tank via an extinguished boiler is prevented.

The pump group contains:

  • Circulation pump Grundfos UPSO 65 Low Energy
  • Thermostatic mixing valve
  • Automatic balancing valve for bypass
  • Floating check valve
  • 3 thermometers
  • 3 5/4“ ball valves with cap nuts
  • Neat insulation to minimize heat loss
Technical Data
Voltage 230[V] 50 [Hz]
Max. working temperature 110° [C]
Min. working pressure 10 [bar]
Circulation pump Grundfos UPSO 65
Low Energy
Max. flow rate at a diff. pump
3……2800 [l/h]
2……2200 [l/h]
1……1400 [l/h]
Connection dimensions 5/4“ [F]
Body material brass
Dimensions 210 × 210 × 110 [mm]
Weight 4,8 [kg]



Model Min. water temperature
into boiler
Max. boiler
Description Code
LK810 – 55 55 °[C] 90 [kW] Pump group with a thermostatic
controlled minimum return water
temperature into a solid fuel boiler,
with an exchangeable thermostatic
LK810 – 65 65 °[C] 60 [kW] 10302
LK810 – 70 70 °[C] 45 [kW] 10551