Low water pressure can be a real frustration for homeowners, with them often looking to installers for the answer. Stuart Elsy, managing director of OSO Hotwater, looks at the measures that can be taken to ensure that flow meets expectation and the options available if a further boost is needed. 

For homes with one bathroom a combi boiler is an ideal option to make the most of incoming water flow rates. Yet, with busy lifestyles now the norm, having the time to wait around for a spot in the shower can seem like a luxury. This leads to new bathrooms and en-suites being added to a property or homes wanting to be able to run more than one outlet at any one time.

Of course, a boiler and cylinder combination is the best option to cope with this demand. With the ability to run multiple showers at once, the benefits speak for themselves.

However, the issue of pressure can still cause problems.  

Swap vented for unvented

Poor pressure and flow to hot water outlets can often be as a result of a vented hot water system. Of course, a pump to increase flow to showers is perhaps the first point of call.

However, if the homeowner is looking to replace their hot water cylinder, suggesting swapping the system with a mains pressure unvented cylinder will dramatically improve both pressure and flow by maximising incoming water flow rates when delivering hot water to each outlet.

This equally has the benefit of removing the cold-water tanks from the loft space, giving a homeowner more useable space and maintaining a sealed system. Couple with an A-rated hot water cylinder, and the two will provide even greater flow and efficiency results.  

Tackling Low Flow Rates

In the great majority of cases the flow rate coming into a property is sufficient to support an unvented system, but there are instances where this is not the case. It should be stressed that this problem only affects a tiny minority to unvented cylinder installations. However, when it does, it is a pain. 

People often think that this is problem of a mains pressure system, but that is not always the main offender; it is usually a result of the available flow rate to the property being insufficient to drive the unvented system to the satisfaction of the customer. This most typically shows itself when the running of a second shower reduces the pressure or flow to the first. A pump cannot be connected to an unvented mains pressure hot water cylinder; so, where do you go next?

Rural areas at the end of a long mains supply are an obvious candidate to be affected, as the water is losing pressure as it travels to the properties. What is perhaps more surprisingly, is that this issue can equally affect a new estate where the pressurized hot water system is not yet updated or upgraded to cope with increased demand.

Accumulating Pressure

Fortunately, there are options available that guarantee to boost flow rates without the need to dig up the road to alter the pipe width; which can prove expensive and time consuming, and often doesn’t solve the problem.

The installation of a cold-water storage system with the addition of accumulator technology, such as OSO’s SuperstreamTM, is guaranteed to boost dynamic pressure, especially in large properties with multiple outlets, as high flow rates can be assured even where an incoming mains flow rate is as low as 5 litres per minute.

Remaining simple in its working, the accumulator system is most easily understood by describing it as an over-sized potable expansion vessel. It works by storing water in a hygienic water chamber that incorporates a virgin butyl diaphragm, this diaphragm then delivers the water at pressure to the cylinder and cold outlets when demand exceeds the mains flow rate available. As the chamber is sealed it ensures water remains drinkable.

This energy efficient technology guarantees to supply greatly increased flow rates and good shower pressure for multi-outlet demand and can be used to boost both hot and cold supplies. Although this technology is not new and has been proven for over 20 years, many installers may not come across it very often and the option can be often overlooked.

Installation remains simple too as no alteration to a property is required.  The accumulator can be installed remotely to the cylinder by connecting to the cold supply after the stop cock via a 28mm pipe which is then run to the to the cylinder. A 22mm cylinder can often be used, but for the most challenging circumstances, couple the accumulator with a hot water cylinder offering a  1” inlet and hot water outlet connections. The wider bore connections will offer greater flow rates. 

A 22mm or 28mm upstream fitting kit is required to connect the accumulator to the cold mains. The hot water cylinder will utilise its own G3 fittings kit.  Where space is an issue, it is often possible to fit the accumulator horizontally using a cradle.

This zero heat loss system is equally at home in commercial situations too, improving shower performance for hotel guests or visitors to sports centres.

If the static mains pressure is in excess of 2 bar, the accumulator system will work, but in the rare cases where mains pressure falls below that figure, the option of a WRAS approved pump specifically designed to work with accumulators will raise the pressure in an accumulator system to 3.5 bar if required.

With no working parts, an accumulator requires no further maintenance and is not affected by power failures so there will be no unexpected loss of pressure for the end user. The system is silent in use – unlike many pumps – and needs no power, meaning no running costs & a 100% green solution. 

So, for occasions where an unvented system is installed and flows remain low, it is worth having the accumulator answer up your sleeve to provide this cost effective, easy-to-install boost when needed. OSO’s energy- efficient SuperStreamTM accumulator comes complete with a 5-year guarantee for added peace of mind.

As this is not necessarily an issue that arises on a day to day basis, Team OSO is on hand to advise whether recommending this type of technology will make a difference to the job in hand, and can provide bespoke advice to installers to assist with requirements. For more information on OSO’s award winning cylinder range visit our product page today,