Issue 3
13/01/21
7
Pipework
It is imperative to achieve balanced supply of hot and cold water in a mains pressure
system, and that the piping in a dwelling should be sized in accordance with
BS 6700
.
However, the following rule of thumb guidelines should be adequate for most of the
smaller property types as long as water pressures are within the recommended range.
•
The cold feed from the main incoming stop tap to the MULTI
flow
should be run
in
22mm
pipe. The cold main and hot draw-off should also be run in
22mm
as far
as the branch to the bath tap.
•
A
15mm
copper or equivalent external service may be sufficient for a small 1
bathroom dwelling (depending upon the flow rate available), but the minimum
recommended size for new dwellings is
22mm
(25mm MDPE).
•
The internal branches to the hand basins and sinks should be in
10mm
and to the
baths and showers in
15mm
. (1 metre minimum)
•
A pressure reducing valve must be fitted after the stopcock of where the
incoming cold supply enters the property and at least 2 metres away from the
inlet to the Secondary Water Coil.
Discharge/Overflow Requirements
The MULTI
flow
is a Vented Thermal Store and therefore does not require safety
discharge from a Pressure and Temperature Relief Valve as highlighted in Part G of the
Building Regulations.
The MULTI
flow
Thermal Store can be sited anywhere within the property as no
discharge pipework is required. A manual fill Feed and Expansion tank is provided as
standard and we would recommend wherever possible, to ensure an overflow pipe is
connected to a suitable discharge point.
On the OV model, if an open vented central heating system is to be run, ensure a
minimum
500mm
from the highest point of the radiator circuit and the bottom of the
Feed & Expansion Tank. Once the unit is filled through the pipework, close off the
isolation valve and disconnect the flexible hose from the pipework and cap the pipe to
avoid any dead legs.
