click to enlarge.
Simple layout of a pressurised hot & cold domestic water supply via cold
Note: This is only for information
purpose and cannot replace a proper designed hot and cold water supply.
Wrongly installed pressurised system can cause injuries
|This simple guide
will help you understand how pressure hot & cold water systems work.
You may be considering installing new, or
changing an existing system to provide pressure hot & cold water at
your taps. This may be an ideal choice for you, but before you make your
decision understand how these systems work and consider all the facts.
|Any system providing
pressure hot & cold water supply is only as good as the supply
entering the property and the storage of cold water. A product may
boast for example - 35 litres per minute flow rate at 3 bar
pressure - but if the supply to your property is inadequate and
can only muster say 15 litres at 1 bar, you have to increase the
size of your cold water storage tank. Figures quoted against
products are indicative of their potential based on an adequate
supply of cold water.
|How does it
work? (Hot Water)
|In general, a
pressure domestic hot water system works by the mains
supply is connected to the cold storage tank's) a supply
pipe going from the storage tank to a booster pump, the
pump pressurise the water and supplies the hot storage
tank with water, by means of heating water in the hot
water storage the hot water taken directly to be delivered
to your taps. There are several ways to do this and many
find different manufacturers interpretations on product
The cold water is taken before the hot water storage tank
and piped directly to your taps.
|There are two
main types of domestic Pressure Hot & Cold Water
Domestic Hot & Cold Pressure Systems
Domestic Hot & Cold Pressure Systems
The term vented refers to
whether the system is partially vented to atmosphere or
completely pressurised and therefore unvented.
|In an unvented
system, incoming pressurised cod water typically
enters a hot water tank suitable for pressurised water up
to 10 -13 bar (for example: a Solar storage tanks made by
Huch and are available from us, where it is heated either directly by means of
electrical heater/s immersion or external type, or indirectly
by means of heat exchanger's) within the vessel being
supplied by your solar thermal system or central heating
boiler. The hot water stored within the vessel is
forced out by the incoming cold water pressure when you
open a tap hence - Pressure Hot Water.
|In a vented
system, heat is imparted to the incoming pressurised water
by means of a secondary heat exchanger within the
"hot water storage tank". Water in the vessel is
used rather like a battery for heat - a thermal store. The
incoming water passes through it's heat exchanger
within the vessel drawing heat from the store. The Thermal
Store temperature is maintained in the usual way - either
directly with electrical heaters, or Indirectly by your
boiler or solar system.
Because the water within
the Thermal Store does not need to be under pressure (as
with an unvented system) it is vented to atmosphere. The
body of water within the thermal store is used purely as a
medium for storing and imparting heat to the secondary
of a pressurised hot water system
bye-laws you may not add a pump directly to your mains to
increase the flow rate to your storage tanks. If the mains
supply to your house is poor there will be no simple way
to improve it. Additional performance usually entails
bringing in a new, larger supply pipe to the property.
Even then, you should ensure the new improved supply will
be adequate, as some areas suffer from frustratingly low
Always remember - your
system can never be better than the supply to it you can
add storage tanks to increase the amount of water stored.
Pressurised systems are at
the mercy of fluctuations in supply pressure and storage.
This may not be an issue in the majority of cases.
Pressurised systems can
give 'power shower' performance, providing mains
supply is good. If you like a vigorous showering
experience and your mains supply is poor and your storage inadequate
remember some booster pumps will pump 35 -95litres
of water per minute.