Gulfstream GS A-Class 12/OV, Инструкции по проектированию, установке и обслуживанию

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Page 12
3.2.1 Mains pressure and water supply
(a) GulfStream
A-CLASS
is designed to be connected directly to the mains and fulfill the
requirements of Water Byelaw 91 and therefore do not require a check valve to
be fitted to the supply pipe. However should ancillary equipment requiring a
non-return valve be fitted to the same mains supply as the GulfStream, then this
valve must not be fitted between the inlet of this mains supply to the property
and the GulfStream (see figure 3.1).
(b) The hot water flow rate achievable from the GulfStream
A-CLASS and the performance
of the domestic hot and cold water systems is directly related to the adequacy of
the cold water mains serving the property. For this reason the cold water supply
to the dwelling must be capable of providing for those services which could be
required simultaneously and this maximum demand should be calculated. Also if
a water meter is fitted its nominal rating should match the anticipated maximum
simultaneous hot and cold water demand calculated in accordance with BS 6700.
This could be 50 litres per minute in some properties.
(c) The GulfStream A-CLASS -OV models will operate at pressure as low as 1 bar but the
recommended range is between 2 and 3 bar. These pressures must be dynamic
and be available at the appliance when local demand is at its maximum.
(d) The GulfStream
A-CLASS
-SS models are fitted with an automatic filling device which
charges the system to 1.0 bar and for this to work correctly; a recommended
dynamic pressure of between 2-3 bar must be available to the appliance at all
times.
(e) As a general guideline, although a 15mm service may be sufficient for smaller
dwellings with one bathroom, a 22mm service (25mm MDPE) is preferred and
should be the minimum for larger dwellings.
(f) If the incoming mains pressure exceeds 5 bar at any time in a 24 hour cycle, then,
a pressure regulating valve set at 3.5 bar should be fitted down stream of the stop
tap where the cold supply enters the property.
(g) Equipment used in the system should be suitable for a working pressure of up
to 5 bar.
3.2.2 Use in Hard Water Areas
(a) The control system prevents the domestic water from exceeding 55
o C for most of
the operational time of the appliance and therefore limits the formation of scale
in the same way as an in line scale reducer.
(b) Therefore it is NOT NECESSARY to fit any form of scale inhibiting equipment in
the domestic cold water supply branch to the appliance, provided hardness is
less than 250ppm. However, the installer should follow the recommendations in
the Benchmark guidance notes covering water treatment.
(c) In extreme conditions (greater than 250 ppm) a Gledhill scale reducer can be
fitted for a nominal cost inside the unit if ordered at the same time as the unit.
(d) If it ever becomes necessary, the plate heat exchanger is easily replaced with a
service exchange unit without complete drain down.
3.2.3 Cold and hot water distribution network
(a) As a minimum, it is recommended that the cold supply to the appliance internally
is run in 22mm copper or equivalent in plastic and then from the appliance in
22mm past the hot water draw-off to the bath .
SYSTEM DESIGN