Disappointing water pressure? How to give the system a boost
In many parts of the UK, householders are having to put up with low water pressure, with the existing water supply struggling to cope with increased demand from ensuites and multiple showers. Duncan Lewis from Dutypoint explains how installers can best come to their customers’ aid.
Low water pressure has been a frustration in a number of households for many years and the problem does not seem to be going away. The symptoms we hear reported are typically around poor flow rates and fluctuating water pressure, as well as not being able to use more than two outlets effectively at the same time. Combi boilers can also struggle to fire up on demand.
Other challenges can include water supply pipes not being sized correctly, particularly in older properties where pipes are partially blocked, therefore further reducing the throughput of water.
Simply looking at these issues and installing an individual solution, such as a shower pump and accumulator vessel, may not be sufficient to resolve the problem – especially in larger properties or multiple dwellings, where a more powerful system is required to boost the whole system rather than individual outlets.
Unfortunately, low water pressure is not an uncommon problem in the UK, with water companies – themselves under financial obligations to reduce leakage rates – having to reduce pressure in their water systems which in turn exacerbates the situation for the domestic user and beyond.
Under the Ofwat Regulation: Low Pressure (GSS Regulation 10) stipulates that “the company must maintain a minimum pressure in the communication pipe of seven metres static head (0.7 bar)” at the boundary of the property. Providing the water company is supplying more than this pressure, there is no legal obligation for them to do anything to increase the supply pressure to residential properties.
Regrettably, 0.7 bar is not sufficient to efficiently run most combi boilers which require at least 1.3 bar to work effectively and, with fluctuating demand on the water supply pipe, this serves to intensify the problem. Consumers usually find the issue at certain times of the day when the demand is high – typically early morning or around dinner time – when you need good pressure to work the washing machine, two showers and make a cup of tea.
Over the last decade or so, we have seen trends in housing developments and home improvements change, meaning there has been a huge uplift in additional bathrooms, shower rooms and ensuites. However, very often these are added without careful consideration of how the existing water supply will cope.
The other challenge is that you cannot simply connect a pump straight into the mains water when the flow rate needed is above 12 L/min (except on very rare occasions, and with special permission from the water undertaker).
Typically, you will need a pressure booster pump set that is separated from the water mains by a break tank. Break tanks have an air break between where the water comes in and where the level stops. This prevents water from flowing back into the mains and potentially contaminating down the line. The break tank is used as a reservoir of water that the pump draws from to provide whatever flow rate is required to satisfy the system’s requirements.
To get the best product it is necessary to assess the following points which will assist in deciding which booster set is needed:
• Decide the pressure needed to come out of the shower or tap, there are standard and high flow shower heads, a nice powerful shower needs around 2 bar.
• Consider the height of the building, from where the pump is located to the highest shower.
• Sum up all the appliances in the house and calculate the draw-off flow-rates; published guidance can be found in BS EN 806 (Part 3) with a complimentary guide BS8558.
• Calculate the friction losses there might be the pipes based upon their diameter and peak flow-rate.
Today, there is certainly a need for a solution that works to combat the varying demands of a modern house, but avoiding the costly installation of a new larger mains supply, redecorating, overcoming regulated shower/tap usage and reduction in noise levels during operation. With the above information it is possible to select the correct pump set and associated tank.
There is a legal requirement to comply with The Water Supply (Water Fittings) Regulations 1999 in England & Wales, 2009 Northern Ireland and 2014 Byelaws Scotland. These regulations cover the design, installation, operation and maintenance of water fittings, systems and appliances.
The water undertaker retains absolute discretion in assessing whether a product complies with the regulations, although the most widely accepted method of demonstrating compliance is an approval certificate from an accredited laboratory, such as WRAS or Kiwa UK (KUKreg4). This proves that the product has passed a set of stringent tests to ensure that it is suitable and safe to convey wholesome (potable) water.
It is important to check the details of any certificate provided to ensure that the approval covers the product as a whole rather than separate components and that the specific model to be installed is covered.
With many types of design on the market ranging from a single pump with pressure switch control, pump and accumulator through to multiple pumps and variable speed controls, all offer the consumer a different solution.
One market leading solution is an integrated pump and tank, such as a Dutypoint ScubaTANK which has been designed to have pump/s installed in a reservoir of stored water. The tank is sized to cope with maximum demand and is able to supply instant pressure and automatically vary its output dependent upon the usage of water within the building. With full WRAS and KUK reg4 approvals, the ScubaTANK also offers the added advantages of a reduced footprint, energy efficiency, easy installation and quiet operation – plus the benefit of at least a decade of refinements. It’s one solution that is helping to provide a boost for a growing number of properties.