Sealed Water Systems; Safety Valve; Expansion Vessel; Pressure Gauge - Vaillant eco TEC plus 415 Instructions Manual

3 General requirements
3.17

Sealed water systems

The installation must comply with the appropriate
requirements of the current issue of BS4814, BS5449,
BS6759, BS6798 and BS7074 Part 1 and 2. For IE your
attention is drawn to the current edition of IS 813.
See fig 3.10 for a suggested layout.
3.17.1

Safety valve

A safety valve must be fitted to a sealed system.
It shall be preset, non-adjustable with a lift pressure
of 3-bar, incorporating seating of a resilient material, a
test device and a connection for drain.
The safety valve discharge pipe must be routed to
outside the building, must not discharge above an
entrance or window or any type of public access area,
be clear of any electrical fittings and positioned so
that any discharge can be seen.
3.17.2

Expansion vessel

A diaphragm type expansion vessel, conforming to
the current issue of BS4814 (see also BS7074 Part
1 and 2). For IE the current edition of IS 813, must
be connected at a point close to the inlet side of the
circulating pump, see the Typical installation, Fig. 3.10.
unless laid down differently by the manufacturer.
The expansion vessel volume depends on the total
water system volume and the initial system design
pressure. For any system an accurate calculation of
vessel size is given in the current issue of BS5449 and
BS7074 Part 1.
Example: For an initial design pressure of 0.7 bar, the
minimum total vessel volume required is 0.063 x Total
System Volume.
Fig. 3.10 Typical installation
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Note!
A higher initial design pressure requires a
larger volume expansion vessel.
The charge pressure must not be less than the
static head of the system, that is, the height of the
highest point of the system above the expansion
vessel.
3.17.3

Pressure gauge

A pressure gauge with a set pointer and covering
at least 0 to 4 bar (0 to 60 lb/in2) shall be fitted
permanently to the system in a position where it can
be seen when filling the system.
3.17.4

Water make up

Provision should be made for replacing water loss
from the system using a make up bottle mounted in
a position higher than the top point of the system,
connected through a non-return valve to the return
side of either the heating circuit or the hot water
cylinder.
Alternatively, provision for make up water should be
made using a proprietary filling loop.
3.17.5

Filling a sealed water system

Provision for filling the system at low level must be
made. This can be achieved by the use of a proprietary
filling loop.
Installation and Servicing ecoTEC plus