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UNIQ HEAT BATTERIES REFERENCE MANUAL_V2.3
4.
Design of cold and hot water supplies
4.1.
General requirements
a)
Minimum dynamic mains water supply pressure
= 1.5bar
b)
Maximum dynamic mains water supply pressure
= 10.0bar
c)
Minimum mains cold and hot water pipe sizes (Up to UniQ HW 9, UniQ Dual 9 models) = 22mm copper or
equivalent
d)
Minimum mains cold and hot water pipe sizes (Above UniQ HW 9, UniQ Dual 9 models) = 28mm copper or
equivalent
e)
Expansion vessel charge pressure (If fitted) = Incoming mains pressure (bar)
Note:
Although the heat batteries are designed for 10bar maximum working pressure, it is recommended that if the incoming
mains pressure is greater than 5bar, a WRAS approved pressure regulator set at 5.0bar should be fitted for comfort of the
occupants.
4.2.
Water distribution network design
a)
The water distribution network should be sized and designed to comply with the requirements of the relevant
sections of:
b)
BS EN 806-1:2000, BS EN 806-2:2005, BS EN 806-3:2012, BS EN 806-4:2010, BS EN 806-5:2012, Design,
installation, testing and maintenance of services supplying water for domestic use within building and their
curtilage
c)
Domestic Building Services Compliance Guide 2013 edition incorporating 2018 amendments
d)
The Water Supply (Water Fittings) Regulations i.e. WRAS
4.3.
Hot water circuit expansion vessel sizing
Unlike the vented and unvented cylinders, the hot water in the heat batteries is heated instantaneously on demand just
like a gas combination boiler and the stored water content is very low (Less than 15 litres in most models
–
See technical
specification section 4 in this manual).
Therefore, the expansion vessel is not
normally required.
However, the expansion vessel should be
sized and fitted as shown schematically in
figure 4.1 if the cold water mains coming
into the building is fitted with a non-
return valve which would prevent the
water from the heat battery expanding
back into the cold water mains during the
heating phase.
[
Note:
Cold water supply into apartments
and water meter assemblies are normally
fitted with a non-return valve
].
The expansion vessel for the DHW heating batteries can be sized using equations 1
–
3.
V
E
= (V
HB
x E
C
) / (1
–
P
1
/P
2
)
----- [1]
P
1
= P
I
+ 1.014
----- [2]
P
2
= P
F
+ 1.014
----- [3]
Water meter
Assembly
Mains cold
water supply
3
2
Figure 4.1
1
Potable water expansion vessel
2
Thermostatic blending valve
3
Building hot water supply
4
Building cold water supply
4
1
Heat battery