gledhill Torrent GreenHeat TGH140-OV Design, Installation & Servicing Instructions page 15

Mains Water Supply
A typical arrangement of the hot and cold water system is shown below. All Torrent
models are designed to be fed directly from the mains and they fulfi l the requirements
of Water Bylaw 91, and therefore do not require a check valve to be fi tted to the cold
water supply pipe.
The performance of the Torrent is directly related to the cold water supply pressure and
volume to the dwelling. This must be capable of providing for all those services which
could be required simultaneously and the maximum demand should be calculated
for sizing the distribution network.
As a general guideline, although a 15mm external service may be suffi cient for the
smaller dwelling with one bathroom, a 22mm service is preferred (25mm MDPE) and
should be the minimum for larger dwellings.
The Torrent will operate at dynamic pressure as low as 1.5 bar (at the appliance) which
must be available when the local demand is at its maximum, but the preferred range
is between 2 and 3.0 bar.
If the incoming static mains pressure exceeds 5.0 bar at any point in the 24 hour cycle,
then a pressure limiting valve set at 3.0 bar should be fi tted downstream of the stop
tap where the cold supply enters the dwelling.
If a water meter is fi tted in the service pipe, it should have nominal rating to match
the anticipated maximum simultaneous hot and coldwater demand, calculated in
accordance with BS 6700. This could be up to 50 l/min in some properties.
The sanitary water equipment used in the system should be suitable for a working
pressure of 10 bar and the units must be fi tted strictly in accordance with the
requirements of the Local Water Undertaking and the relevant Water Bylaws.
Second dwelling
Supply
pipe
Pressure limiting valve
(Not required unless mains pressure is greater than 5 bar)
Sink
Check valve NOT REQUIRED unless scale inhibitor is a chemical type.
In any event, do not fit a check valve down stream of this point (see 5.1.9)
Check valve NOT REQUIRED unless
supply pipe services more than one dwelling
Hot and Cold Distribution Pipe Arrangement - All Models
Page 15
INSTALLATION
Taps and Shower Fittings
Aerated taps are recommended to prevent
splashing.
All types of shower mixing valves can be used
as long as both hot and cold supplies are mains
fed. However all mains pressure systems are
subject to dynamic changes particularly when
other hot and cold taps/showers are opened
and closed, which will cause changes in the
water temperature at the mixed water outlet
such as showers. For this reason and because
thermostatic showers are now no more
expensive than manual showers, we strongly
recommend thermostatic showers with Torrent.
The shower head provided must also be suitable
for mains pressure supplies.
The hot water supply to a shower-mixing
valve should be fed where practical directly
from the Torrent or be the fi rst draw-off point
on the hot circuit. The cold water supply to a
shower-mixing valve should where practical
be fed directly from the rising mains via an
independent branch.
The shower must incorporate or be fi tted with
the necessary check valves to prevent back-
syphonage protection in accordance with Water
Regulations.
The supply of hot and cold mains water directly
to the bidet is permitted provided that it is of
the over-rim fl ushing type and that type 'A' air
gap is incorporated.
Scale inhibitor
(where necessary)
Bath
TYPICAL HOT AND COLD DISTRIBUTION
BS1212
Ballvalve
W.C.
H.B.
INSTALLATION