Heat Pump Buffer Vessels

The Aquinox Heat Pump Accumulator Tank is utilised to add volume to your existing heating system; heat pumps require a minimum system volume in order to function efficiently so the addition of a Heat Pump Accumulator ensures a consistent flow-rate and system volume are maintained. A heat pump will keep emitting heat even with no demand, a Aquinox Buffer will facilitate the storage of this excess heat for later use. 

Unlike most units on the market, we manufacture our buffers from 316L Stainless Steel for it's resistance to corrosion.

As the buffer vessel will contain warm water, it will prevent the heat pump going into defrost mode during cold temperatures as warm water will remain cycling.

If you’re not sure whether your heating system requires a buffer tank (as not all do), or what size vessel would be necessary, we would suggest consulting your heat pump installer and/or supplier for advice.

Having an Accumulator reduces the risk of short cycling, which can lead to inefficiencies and even damage to the heat pump system, leading to a longer lifespan for the system and the heat pump unit itself.

Our buffer vessels range from 15 Litres to 100 Litres covering most requirements for the heat pump market. If you require a larger buffer vessel you can view our range here or get in touch.


  • Working Pressure - 4.0 BAR
  • Test Pressure- 7.0 BAR
  • Operating Temperature - -10°C to 95°C
  • 4 x 1" Female Connections
  • 1/2" Auto Air Valve
  • 1/2" Thermostat Pocket Connection
  • Includes Wall or Floor Mounting Brackets
  • 5 Years Warranty

Sizing Table

Size Armaflex Steel Case Volume
300x184mm 320x205mm 340x225mm 8 Litre
450x184mm 470x205mm 490x225mm 12 Litre
430x200mm 450x220mm 470x240mm 15 Litre
650x200mm 670x220mm 690x240mm 20 Litre
700x200mm 720x220mm 740x240mm 25 Litre
820x250mm 840x270mm 870x300mm 40 Litre
975x250mm 995x270mm 1015x290mm 50 Litre
760x375mm N/A 820x450mm 80 Litre
950x375mm N/A 1010x450mm 100 Litre

How to Order

Our Buffer Vessels are made to order and can offer discounts on volume orders, for more information please get in touch at;

Call us on 01636 678437

Email us at [email protected]