How to Specify the Right Accumulator Tank

AccuBoost Accumulator vessels offer a great solution to low water pressure in a home, however, with so many different vessels available, choosing the right accumulator for the job can seem like a complicated process.

To help simplify the specification process, our Training Manager, Mike Oxley, explains how to choose the right accumulator vessel system.

1. Does the home have a combi boiler or an unvented system?

Accumulator vessels are suitable for both combi boilers and unvented systems. However, while all options are suitable for a combi boiler, a home with an unvented system requires a minimum of 330 or 450 litres capacity.

2. Pumped or unpumped?

A pumped vessel should be specified for homes with water pressure below 2.0 bar, water flow below 12L/min, or when the highest outlet is on the second floor or higher. However, if the home has a lead or restrictive mains an unpumped accumulator could still be effective.

All AccuBoost accumulator vessels are available as both pumped and unpumped models.

3. What size accumulator vessel do you need?

To specify what size accumulator vessel a home needs, calculate the flow rate (l/min) of the outlets in the home that you want to run at any one time. You can then identify the correct accumulator vessel sizing to provide this flow rate for a minimum of nine minutes – the average length of a shower.

As a rough guide, here is a breakdown of what pumped vessels can offer for nine minutes (after this they will then continue to offer at least 12l/min through the pump):

60L vessel – up to 14l/min

120L vessel – up to 16l/min

180L vessel – up to 18l/min

330L vessel – up to 30l/min

450L vessel – up to 36l/min

Our product selector features an accumulator vessel calculator which will determine, depending on the flow needed by the outlets in the system, what size accumulator vessel is needed.

4. How much space is available?

In general, a 60L model will fit into a standard 500mm kitchen base unit; a 120L model into a 500mm larder style kitchen unit; and the 180L/330L model into a 600mm larder style kitchen unit with the back removed (although the vessels don’t have to be situated in the kitchen).

If space is limited, you may need to specify a smaller vessel, which would mean running fewer outlets simultaneously. However, an alternative option would be to link multiple vessels together to gain additional capacity and make the solution flexible to the available space.

5. Still unsure?

If you’re still unsure which accumulator vessel is right for your needs, Salamander Pumps has an easy-to-use online product selector tool to identify which vessel is best suited to the job in hand.