500 Litre buffer tank or vessel

500 Litre Buffer Tank or Vessel

500 Litre buffer tank or vessel with energy class c insulation levels hot water storage for hydronic heating systems


Our 500 Litre buffer tank or 500 litre buffer vessel, is a hot water buffer tank normally used to store heating hot water or increase the heating system’s hot water volume. This energy is retained for later use and results in fewer but longer heating cycles for the heating system with our buffer tanks or accumulator tanks.

500l buffer tank for a heating system

This 500L buffer tank ( also called a 500l thermal store)  can be used on various heating systems, but is often used in conjunction with renewable heating systems such as biomass boilers or low carbon systems such as ground source heat pumps or air source heat pumps as a heat source.

Air source heat pumps

For a heat pump to operate at peak efficiency, our buffer tank, also known as a buffer vessel, ensures minimal compressor run times and minimum water flow rates. For air source heat pumps, a buffer tank is necessary because it supplies the defrosting energy for the heat pumps. If a heat pump is the only source of heating, it is also possible to integrate an electric immersion element to provide additional heating as needed to our multi port buffer tanks.

Specification of our buffer tank or vessel

Technical specifications of our 500 Litre buffer vessel , 500l buffer tank or 500l thermal store.

500 litre buffer tank or vessel drawing showing dimension and tapping detail Flexiheat UK

Our 500L buffer vessel or tank – overall height 1,735 mm, overall diameter 760 mm with insulation – 600 mm diameter with insulation removed.

Tank storage capacity – 500 Litres nominal – 479 Litres actual tank volume

Height – 1,735 mm

Diameter with Insulation: 760 mm – which allows you to get the buffer tank through a standard 800mm door way

Diameter without Insulations: 600 mm

Product insulation is polyurethane – 55 mm insulation

Insulation specification – Rigid expanded polyurethane with 95% closed cells, CFC and HCFC free, fire resistance class B2 according to DIN 4102-1

ErP rating – “C” rated with only 90 Watts heat losses

Flexiheat hot water buffer 500 Ltr capacity –

Our 500l buffer tank or accumulator tank is a great quality product at a great price.

This 500L buffer tank is manufactured from mild steel

500l buffer tank weight – 108 Kg when empty – 577 kg when full with hot water

8 x connection tapping’s – 40 mm (1 1/2″ ) female bsp – for the heat source or outlet designated “DN1,DN2,DN3, DN4, DN11, and DN18 ” on the above drawing

4 x Thermometer or sensor pockets – 15 mm (1/2″) female bsp – designated “DN15″ on the above drawing (sensor pockets are 1/2” female threaded).Any thermometers can be ordered separately from us.

1 x Air vent eliminator or safety valve tapping or bsp safety connection – 15 mm ( 1/2″) female bsp- designated “DN15” on the above drawing

Angles of the tapping ports as seen from above the 500 litre model.

500 Litre buffer vessel tapping data from the top of the vessel or tank Flexiheat UK

Buffer tank maximum working temperature – 95 Degrees Celsius

Buffer tank maximum working pressure – 8 Bar

With plenty of tapping’s this 500L buffer tank can be fitted with additional immersion heaters as a backup or top-up heat source.

This 500L buffer tank is manufactured from mild steel, so corrosion inhibitors must be used with this product.

Full port dimensions off the floor for our 500 Litre model is listed in the following brochure.

Download the Flexiheat UK 100 to 5,000 Litre buffer Plus range of heating buffer tanks vessels brochure

Should you require another capacity or volume buffer tanks, a higher working pressure or a stainless steel version, then we do a full range of buffer tanks which are listed on their dedicated webpage.

Applications – hydronic heating systems

Our 500l buffer tank can be used with heat pumps, log fired boilers, gasification boilers, wood pellet boilers, or even traditional gas or oil boilers, Flexiheat UK offers a variety of multi-port buffer tanks and accumulator tanks.

Sizing criteria for a 500l buffer tank

Here are some guidelines on sizing for our 500L buffer tank

Air source heat pumps or ground source heat pumps: approximately 25 litres per kW of heat pump output (recommended by BS EN 14511 for defrosting of the heating system).

Wood pellet boilers: a minimum of 10 litres of tank volume for every 1 kW of boiler output.

Solid fuel boilers: a minimum of 30 litres of tank volume for every 1 kW of boiler output.

Wood chip boilers: a minimum of 12 litres of tank volume for every 1 kW of boiler output

Gasification boilers / log fired boilers: a minimum of 50 litres of tank volume for every 1 kW of boiler output.

Thermal storage tank or vessel 500 Litres capacity

If you require more product information, availability, technical support , check stock levels, delivery times or get prices on our 500 Litre buffer tank or vessel for heating hot water, then please don’t hesitate to get in touch. Contact our sales service team on 01202 822221 or use our email contact form via the contact tab above to message us. Connect with us on Facebook or Twitter for our latest products updates and special product price deals.