The amount of water available to the tap
is important when choosing which product to buy. The cold
water supply is at mains pressure so is generally not of
importance; the tap however will require the correct amount
of hot water pressure to perform satisfactorily.
Water pressure can be measured in three common units, bar,
psi and Head (m).
1 bar = 10 metres Head = 14.5 psi.
Hot water pressure:
Domestic hot water systems generally fall into two categories
pressurised and un-pressurised.
Pressurised water heaters (instantaneous gas water heaters
or modern combination boilers) deliver a continuous large
volume of hot water.
For Combination boilers or instantaneous water heating
systems the boiler output is typically around 20 psi =
1.8 bar = 18m head. This means most taps should give good
flow rates with these types of system.
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Un-pressurised water heating systems found in older houses
generally have a cold water storage tank in the loft and
a heater tank on the first floor. The vertical distance
between the header tank and the tap outlet gives an approximate
calculation of the available hot water pressure.
In general terms most single storey houses or bungalows with
un-pressurised systems do not suit ‘high’ pressure
taps such as single lever mixers for example.
For this reason abode’s range includes several ‘low’ pressure
mixertaps. Alternatively a booster pump can be fitted to increase
the available water pressure, allowing a wider choice of models.
Cold water Pressure:
Cold water pressure is rarely an issue as it is normally provided
from the municipal high pressure supply.
If you live in on the higher floors of a tall building or draw
your cold water from a private supply you should check the
available cold water pressure. Use the stated minimum water
pressure in these cases for both the hot and cold supplies.
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The diagram shows a simplified un-pressurised system, for
example if the vertical distance was 5m this would roughly
equate to 0.5 bar maximum available pressure.
Note: if the route the pipes take is not direct, has lots
of bends or long horizontal runs the available water pressure
will be reduced. |
