gledhill TORRENT DIRECT Design, Installation & Servicing Instructions page 26

HEATING SYSTEM DESIGN
The flow pipe between the boiler and the Torrent thermal store is part of the open vent
and therefore it must not be fitted with any isolating valve, non-return valve or any other
component which can obstruct the flow.
The minimum size of flow and return pipe between the boiler and the Torrent should be
22mm copper or equivalent. In any case it should be sized to suit the installed boiler
capacity, available pump head and the circuit resistance.
(e) The water level must be set correctly by adjusting the ball valve in the F&E cistern. A
22mm connection is provided for the overflow/warning pipe, which should be no less than
the 20mm internal diameter and have a continuous fall.
The overflow/warning pipe should be fitted to discharge clear of the building and be sited
so that any overflow can be easily observed. The warning pipe should be installed in
either high temperature uPVC or copper and should not have any other connections to it.
4.4.5 Sealed heating system
(a) All Torrent Indirect 'SP' models are suitable for sealed heating system up to 3.5bar
maximum operating pressure, however the normal pressure relief valve setting is 3.0 bar.
The typical layout of the open vented 'Y Plan' and 'S Plan' for the indirect Torrent models
is shown in figures 4.5 and 4.6 respectively.
(b) A boiler used in a sealed heating system must be suitable for this application i.e. it must
be fitted with an overheat cut-out thermostat.
(c) It is recommended that the F&E cistern (for the thermal store) is fitted at a high level in the
same cupboard as the Torrent. However it can be fitted remotely up to 10m above the
base of the Torrent.
The F& E cistern overflow/warning pipe should be installed in a material suitable for a
heating system feed and expansion cistern in accordance with BS 5449.
(d) There shall be no permanent connection to the mains water supply for filling the heating
system even through a non-return valve without the approval of the Local Water Authority.
An approved filling loop is required for filling the heating system, which should be
disconnected after commissioning the system.
The filling loop should be located adjacent to the boiler along with a suitable expansion
vessel, pressure gauge, pressure relief valve and discharge arrangement.
(e) The table 4.2 can be used for sizing the heating system expansion vessel. The water
content of the Torrent primary heat exchanger is listed in specification tables in section 2
(depending upon the model) and a figure of 4.5 l/kW of installed radiator capacity can be
used for a preliminary assessment of the water content of the heating system.
The expansion vessel requirements shown in table 4.2 are based on a maximum boiler
flow temperature of 93
change in volume of water in the heating system when heated from 10
specified in BS 5449:1990 clause 16.2.
(f) The minimum system pressure should not be less than the static head plus 0.5 bar i.e. the
height of the highest point in the system above the expansion vessel plus a margin of 0.5
bar.
o
C. The expansion vessel must be suitable to accommodate the
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o o
C to 110 C as