Vexve Control products

Vexve Termovar

Loading unit for the connection of wood boilers and thermal storage systems.


  • A factory-ready compact loading package that ensures trouble-free and fast installation of solid fuel boilers and thermal storage systems
  • The loading unit causes the boiler temperature to rise rapidly and loading starts automatically as soon as the operating temperature is reached, thus improving the efficiency of the boiler and increasing its service life
  • At the initial stage of loading, rapid storage tank temperature stratification makes it possible to obtain heat energy very quickly after the start of the combustion
  • The automatic shutoff function closes the by-pass line when loading is nearly complete, thus ensuring that the storage tank is fully charged
  • A free flow valve allows free circulation when the pump stops for recovery of residual boiler heat at the end of the combustion
    The return temperature of the boiler can be adjusted by exchanging thermostats
  • An insulated casing provides thermal protection and saves energy
  • The flue gas thermostat controls the pump, optimizes the operation of the loading unit and saves the boiler from harmful high-temperature changes (standard on some models only)
  • The loading unit is easy to service, all wearable parts are easily replaceable without the need for draining the system


Loading pump: Grundfos UPM3 AUTO L -50 (230 VAC 50/60 Hz 2-33 W)

Maximum boiler output: 65 kW (maximum flow ~2500 l/h)

Maximum operating temperature: 110 °C

Maximum operating pressure: 0,6 MPa (6 bar)

Return temperature: Adjustable with exchange thermostats (45, 49, 55, 61, 66, 72 and 80 °C)

Thread size: Rp 32 or Rp 25 or CU28mm (integrated shut-off function)

Material: Brass

Bypass circulation regulation and shut-off function

Free flow valve

Dimensions (width x height x depth): 190 x 200 x 125 mm

Weight: 3,2 kg

Delivery contents:

Loading unit body

  • Brass

3 thermometers 0–120 °C

  • Loading temperature, boiler return temperature and temperature of the lower part of the storage tank

3 ball valves (full bore with closing handle)

  • 1 ½” x 1 ¼” or 1 ½” x 1” or 1 ½” x CU28mm

Loading thermostat (standard 72 °C, some models include replacement thermostat)

  • Available: 45, 49, 55, 61, 66, 72 and 80 °C opening temperature

Bypass circulation regulation and shut-off valve

  • Automatic operation operated by loading thermostat

Free flow valve

  • Automatic operation

Grundfos loading pump

  • UPM3 AUTOL -50

Modern formulated thermal insulation

  • EPS-material

Flue gas thermostat

  • Standard only in some models.

This device meets the following environmental requirements and standards:

  • Operating temperature 0 … +40 °C
  • Storage temperature −20 … +60 °C
  • Shipping temperature −20 … +60 °C
  • Humidity 0–100 % RH, non-condensing conditions
  • RoHs 2002/95/EC
  • CE-mark 93/68/EEC
  • EMC-directive 2004/108/EEC