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flexoTHERM ground source heat pump

Ground source heat pump


flexoTHERM is a ground source heat pump out of the box which can be connected to either a borehole or a ground array for ground source applications. Using advanced EVI compressor technology, flexoTHERM earns the Vaillant Green iQ badge meaning flexoTHERM is the most efficient product in its range. When installed with a VRC 700 or VRC 700f weather compensating control the flexoTHERM becomes ErP rated A+++.

flexoTHERM has also been awarded "Quiet Mark", issued by the Noise Abatement Society, thanks to its exceptionally low operating noise levels (excludes 230V range). It sounds no louder than a standard domestic fridge of 42dB(A). flexoTHERM is MCS accredited and RHI eligible.

The ground source unit can also be connected to a passive cooling module for projects that require efficient climate control as part of the specification which works by passing warm heating circuit water against cool brine fluid to gently cool down the building.



Technical dataUnit5kW 230V8kW 230V11kW 230V5kW 400V8kW 400V11kW 400V15kW 400V19kW 400v
Minimum flow temperature heating °C2525252525252525
Maximum flow temperature heating with compressor°C6565656565656565
Nominal flow rate ∆T 8Kl/h6009301290570980124016002180
Energy-related Product 35°C*BandA+++A+++A+++A+++A+++A+++A+++A+++
Energy-related Product 55°C*BandA+++A+++A+++A+++A+++A+++A+++A+++
Product dimensions (H x D x W)mm1183 x 595 x 6001183 x 595 x 6001183 x 595 x 6001183 x 595 x 6001183 x 595 x 6001183 x 595 x 6001183 x 595 x 6001183 x 595 x 600
Weight, ready for operationkg157173185151167175187200

*Reported efficiency when used with VRC 700 / VRC 700f controller

Related Products

Related Products

VRC 700 and VRC 700f

  • Takes care of all Vaillant equipment automatically by intelligently communicating with all Vaillant appliances
  • Flexible time programs
  • Clear, high contrast backlit display
  • Programs are permanantly stored


How to get

Request a quote

Vaillant Commercial boilers and accessories are available over the counter or as a next day service at most plumbing and heating merchants throughout the UK.

We can provide you with bespoke solutions to accommodate a variety of installations. To discuss your requirements please contact us.

Alternative products

Alternative products

geoTHERM 22kW, 30kW, 38kW and 46kW

  • "Quiet Mark" accredited thanks to geoTHERM multi-stage sound insulation
  • Energy yield display
  • MCS accredited, RHI eligible

flexoTHERM 400V 5, 8, 11, 15 and 19kW

  • Exceptionally quiet with noise levels as low as a modern refrigerator - 42dB(A), flexoTHERM has earned the ‘Quiet Mark’ approval
  • Compatible with the Vaillant wired VRC 700 and wireless VRC 700f controls, to provide optimum system efficiency and a system rating of ErP A+++
  • Built-in heating circulation pump and a three-way diverter valve
  • Green iQ technology aids in future-proofing the product and ensures optimum efficiency, performance and sustainability