If your existing service pipe has a small bore due to material, corrosion or blockages increasing the bore of the pipe will increase your cold water flow rate. This assumes that there is sufficient water from the main.
This will require a new service pipe from the main to the Stop Tap in your property. There are specific water regulations about the depth this pipe should be laid and how it enters your property.
This could be a costly exercise and you may prefer to consider one of the other options we have detailed.
Where you have a traditional cold water storage cistern in the loft it is possible to install a pump to pump the cold main from the cistern to the cold outlets.
This is will often be combined with a dual circuit pump to provide pumping on the hot water to provide balanced pressure and flow hot water for thermostatic showers.
This can often be an excellent relatively cheap option.
It does, however, have the problem of limited cold water availability. In many houses, the cold water storage cistern in the loft is quite small.
In the case of a whole house pump providing both hot and cold water for the shower the run time of the pump can be limited. This indirectly applies to the hot water from the open vent cylinder which can be depleted of hot water in a few minutes by a pump.
Another issue is noise. Typically the pump is located close to the cold water storage cistern and the hot water cylinder (ie the airing cupboard). Quite often, despite wide and creative attempts to deaden the noise by manufacturers and customers alike, the pump remains noisy and becomes a serious source of irritation over time.
Pumping mains water directly from the main is against regulations but most authorities will allow the use of a small mains boost pump up to a maximum of 12 litres per minute.
This may meet your requirement for a single outlet but is unlikely to meet the required flow rates for multiple outlets.
There are a number of suppliers of this kind of pump the Salamander pumps website is quite informative on this type of pump.
Where increasing the flow from the mains is either not possible or practical it is possible to consider the use of a Home Boost Unit.
This unit consists of a Cold Water Storage Cistern (on the same principle as the cistern found in your loft) together with a pump unit either of variable or fixed speed. The variable speed pump can cope better with fluctuating cold water demands.
The pump is controlled by an integral flow switch.
The mains water flows into the storage part of the unit and is stored in bulk typically 200/300 litres for a domestic property. The flow of incoming mains water is usually controlled by a ball valve.
When an outlet such as for example a tap, toilet, shower, combi boiler or unvented cylinder creates a demand for cold water the pump operates at a predetermined flow rate and working pressure. We would tend to set these at approximately 3 bar and 20 litres per minute on a variable unit.
As an example, if you have a 200 litre storage tank and the pump supplying 20 litres per minute the tank would be empty in 10 minutes. However, the cold main is replenishing the stored cold water. If the cold main was supplying 10 litres per minute then the pump could operate for 20 minutes.
This may not seem long but if you consider whether you are likely to use the supply at the maximum rate for 20 minutes at a time?
It is necessary when considering the use of a home boost unit to consider the potential demand. This will depend upon the number of outlets and showers.
The home boost units come in various sizes and can have add on cisterns to increase their storage capacity
Space can be an issue as to store this amount of water takes a lot of room. Slimline units are available. We would recommend a garage or utility area if possible.
The home boost units are usually best installed at ground level if possible. This is because if you have low pressure and flow on your main the main flow is not affected by height and is maximized.
Home boost units are an excellent answer to the cold water issue. But they also provide so much flexibility that they can be the basis for high pressure and flow hot water solutions.
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