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5. Before installation
5.1 Installation regulations
WARNING
Installation of the appliance must be carried
out by a qualified engineer in accordance
with prevailing and national regulations as
listed below.
Building Regulations G3
`
The Building Standards (Scotland)
`
The Building Regulations (Northern
`
Ireland)
I.E.E Electrical Regs
`
UK Water Regulations
`
5.2 Installation requirements
Water supply
In an unvented system the pressure and flowrate is
directly related to the incoming water supply. For this
reason it is recommended that the maximum water
demand is assessed and the water supply checked to
ensure this demand can be satisfactorily met.
We suggest the minimum supply requirements
`
should be 0.15MPa (1.5 bar) pressure and 20 litres
per minute flow rate. However, at these values
outlet flow rates may be poor if several outlets are
used simultaneously.
A 22mm cold water supply is recommended,
`
however, if a smaller supply exists, which provides
sufficient flow, this may be used (although more
flow noise may be experienced).
The higher the available pressure and flow rate the
`
better the system performance.
See tables 1&2 on pages 5&6 for cylinder operating
`
pressures. This is controlled by the cold water
combination valve assembly.
Outlet/terminal fittings (taps, etc.)
The cylinder can be used with most types of
`
terminal fittings.
Outlets situated higher than the cylinder will give
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outlet pressures lower than that at the heater, a
10m height difference will result in a 1 bar pressure
reduction at the outlet.
All fittings, pipework and connections must have
`
a rated pressure of at least 8 bar (dependant on
cylinder being fitted) at 80°C.
Limitations
The cylinder should not be used in association with any
of the following:
Solid fuel boilers or any other boiler in which the
`
energy input is not under effective thermostatic
control, unless additional and appropriate safety
measures are installed.
12
Ascending spray type bidets or any other class 1
`
back syphonage risk requiring that a type A air gap
be employed.
Steam heating plants unless additional and
`
appropriate safety devices are installed.
Situations where maintenance is likely to be
`
neglected or safety devices tampered with.
Water supplies that have either inadequate
`
pressure or where the supply may be intermittent.
Situations where it is not possible to safely pipe
`
away any discharge from the safety valves.
In areas where the water consistently contains a
`
high proportion of solids, e.g. suspended matter
that could block the strainer,
filtration can be ensured.
In areas where the water supply contains chloride
`
levels that exceed 250mg/l.
5.3 Choice of location
The cylinder must be vertically floor mounted. Although
location is not critical, the following points should be
considered:
The cylinder should be sited to ensure minimum
`
dead leg distances, particularly to the point of most
frequent use.
Avoid siting where extreme cold temperatures will
`
be experienced. All exposed pipe work should be
insulated.
The discharge pipework from the safety valves
`
must have minimum fall of 1:200 from the unit and
terminate in a safe and visible position.
Access to associated controls and immersion
`
heaters must be available for the servicing and
maintenance of the system. Where these controls
are installed against a wall a minimum distance of
250mm must be left (see Fig. 5).
Note of the overall height of the unit in relation to the
`
ceiling height and ensure that access and space is
available for piping/connections to the outlet.
Ensure that the floor area for the cylinder is level
`
and capable of permanently supporting the weight
when full of water (see Table 1, page 5 for weights).
The tundish should be installed away from electrical
`
components.
Wall
Min 250mm
Figure 5: Siting the unit
unless adequate
Min 250mm
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