Booster Set or Accumulator System: Which Is Right for Your Water Supply?

Poor water performance does not always mean poor water pressure.

In many domestic and commercial properties, the incoming mains pressure can be perfectly adequate while the available flow rate is insufficient to meet peak demand. This becomes particularly noticeable where several outlets are being used simultaneously, or where equipment such as unvented cylinders, combination boilers and high-performance showers requires a reliable water supply.

In these circumstances, two potential solutions are commonly considered: a traditional break tank and booster set, or an accumulator system.

Both can improve water performance, but they work in very different ways. Choosing between them depends on the incoming mains supply, expected demand, available space and the level of resilience required.

1What Is An Accumulator System?

An accumulator is a sealed vessel that stores water under pressure. When demand within the property increases, the stored water supplements the incoming mains supply, increasing the available flow rate and helping maintain dynamic pressure when several outlets are operating.

The system essentially stores and makes better use of the energy already available from the mains supply rather than relying on electrically powered pumps. Accumulator systems are typically suitable where there is at least 2.0 bar static incoming pressure but insufficient flow.

This makes accumulators particularly useful where the underlying problem is flow rather than pressure.

2Advantages Of An Accumulator System

One of the biggest advantages is simplicity.

Accumulator vessels require no electrical power supply and have no running electricity costs. They are also silent in operation and do not normally require drainage or discharge arrangements.

There are several other potential benefits.

Improved Flow Rates

An accumulator can provide additional stored water during periods of high demand, helping overcome poor mains flow where the incoming pressure is adequate. This can be particularly valuable where multiple showers, taps or other outlets may operate simultaneously.

Lower Operating Costs

Because the system uses the mains pressure rather than an electrically driven booster pump, there is no ongoing electrical running cost associated with normal accumulator operation.

Flexible Installation

Accumulator vessels can be installed in a variety of locations because they do not require electrical power or drainage. Depending on the property, potential locations can include cupboards, utility rooms, basements, lofts, garages or suitable external enclosures.

Their modular format also means multiple vessels can be linked where greater stored capacity is required.

Sealed Water Storage

Unlike a traditional break tank, accumulator systems provide sealed water storage. This can simplify water hygiene management and remove the requirement for regular tank chlorination associated with some conventional stored-water systems.

Sealed water storage, minimal maintenance and a lower risk of bacterial growth are also key benefits of accumulator technology.

Low Maintenance

With no conventional booster pump running every time demand increases, accumulator systems have relatively few operating components. Purpose-designed vessels can incorporate features such as controlled diaphragms, sealed air valves and corrosion-resistant designs intended to provide long service life.

3So Why Would You Still Use A Booster Set?

Accumulator systems have significant advantages, but they are dependent on the incoming mains pressure.

This is the most important distinction.

An accumulator does not manufacture pressure from nothing. It stores water using the pressure already available from the mains.

An accumulator does not create additional mains pressure; its performance remains dependent on the pressure available from the incoming supply. If the incoming mains pressure is too low, an accumulator alone may not be suitable.

A booster set, usually incorporating water storage and electrically driven pumps, can create and maintain the required pressure independently of fluctuations in the incoming supply.

That makes booster sets particularly important where:

• incoming mains pressure is inadequate;
• a defined boosted pressure needs to be maintained;
• demand is particularly high;
• the application is larger or more complex; or
• greater independence from future mains pressure changes is required.

4Future Mains Pressure Should Also Be Considered

This is an important consideration when specifying accumulator systems.

Water companies may reduce network pressure as part of leakage-management strategies. Because an accumulator relies on the mains pressure available to charge the vessel, a significant future reduction in supply pressure can affect system performance.

A property that has suitable mains pressure today may therefore perform differently if network conditions change in the future.

For projects where long-term resilience to changes in mains pressure is particularly important, a break tank and booster set may therefore offer greater certainty.

5What About Space?

This is another area where the answer depends on the application.

For smaller systems, accumulators can offer considerable installation flexibility. However, increasing demand means increasing stored capacity.

Multiple accumulator vessels can be connected together to serve larger domestic and smaller commercial applications, but the physical footprint inevitably increases as additional vessels are introduced.

At a certain scale, a traditional booster set can therefore provide the required performance within a smaller overall plant area than a bank of accumulator vessels.

Space should consequently be considered alongside pressure, flow and peak water demand rather than looking at vessel size in isolation.

6Accumulator Or Booster Set?

There is no universal answer.

Where mains pressure is good but flow is poor, an accumulator system can be an extremely efficient solution. It can increase available flow without the electricity consumption, noise and maintenance associated with a traditional pumped system.

Where mains pressure itself is inadequate, demand is particularly high, plant space is constrained or the system needs greater independence from future changes in water-company supply pressure, a traditional booster solution may be more appropriate.

The key is understanding what is actually happening at the property before equipment is selected.

7Start With Pressure, Flow And Demand

Correct specification should begin with accurate information about the incoming mains supply and the demands that will be placed upon it.

Accumulator sizing should take into account factors including incoming pressure and flow rates, mains pipe size, number of outlets, occupancy, peak demand, hot-water requirements and any high-volume fixtures such as performance showers.

That is why site pressure and flow testing is essential before deciding between an accumulator and a conventional booster set.

At Bespoke Water Solutions, we assess the incoming supply, expected water demand and requirements of the building before recommending the most appropriate solution.

Whether that is an accumulator system, a traditional booster set or another approach, the objective is the same: to deliver the water performance the building actually requires.

Written by the team at Bespoke Water Solutions, drawing on more than 35 years of experience with water systems, booster applications and bespoke packaged solutions.