Page 10
Page 11
Hot and Cold Water System
Pipe Sizing / Materials
To achieve even distribution of the available supply of hot and cold water, it is
important in any mains pressure system, that the piping in a dwelling should be sized
in accordance with BS EN 806:1-5: BS EN 8558:2011. This is particularly important in
a large property with more than one bathroom.
However, the following rule of thumb guide lines should be adequate for most smaller
property types as long as water pressures are within the recommended range.
1. 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).
2. The internal cold feed from the main incoming stop tap to the BoilerMate CP 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.
3. The final branches to the hand basins and sinks should be in 10mm and to the
baths and showers in 15mm (1 metre minimum).
4.
We would recommend that best results for a balanced system are achieved
by fitting appropriate flow regulators to each hot and cold outlet. This is
particularly relevant where the water pressures are above the recommended
water pressure range. Details of suitable flow regulators are provided in
Appendix A.
All the recommendations with regard to pipework systems in this manual are generally
based on the use of BS/EN Standard copper pipework and fittings.
However, we are happy that plastic pipework systems can be used in place of copper
internally as long as the chosen system is recommended for use on domestic hot
and cold water systems by the manufacturer and is installed fully in accordance with
their recommendations.
This is particularly important in relation to use of push fit connections when using the
optional flexible hose kits - see installation section of this manual.
It is also essential that if an alternative pipework material/system is chosen the
manufacturer confirms that the design criteria of the new system is at least equivalent
to the use of BS/EN Standard copper pipework and fittings.
Hot and Cold Water System
If the length of the hot water draw off pipework is excessive and the delivery time
will be more than 60 seconds before hot water is available at the tap, you may wish to
consider using trace heating to the hot water pipework such as the Raychem HWAT
system. Also a conventional pumped secondary circulation system (shown below)
can be used with any model of the BoilerMate CP.
Bath hot water supplies should be limited to
a maximum of 48°C by the use of an inline
blending valve.
It is important that the cold water pipework
is adequately separated/protected from any
heating/hot water pipework to ensure that
the water remains cold and of drinking water
quality.
Secondary circulation pipework must be
insulated to prevent energy loss in both heated
and unheated areas.
Taps/Shower Fittings
Aerated taps are recommended to prevent
splashing.
Any type of shower mixing valve can be used
as long as both the 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
mixed water outlets such as showers. For this
reason and because these are now no more
expensive than a manual shower we strongly
recommend the use of thermostatic showers
with this appliance.
The shower head provided must also be
suitable for mains pressure supplies.
However, if it is proposed to use a ‘whole body’
or similar shower with a number of high flow/
pressure outlets please discuss with the Gledhill
technical department.
The hot water supply to a shower-mixing
valve should be fed wherever practical directly
from the BoilerMate CP or be the first draw-
off point on the hot circuit. The cold supply
to a shower-mixing valve should wherever
practical be fed directly from the rising mains
via an independent branch. The shower must
incorporate or be fitted with the necessary check
valves to provide back-syphonage protection in
accordance with the Water Regulations.
The supply of hot and cold mains water directly
to a bidet is permitted provided that it is of the
over-rim flushing type and that a type ‘A’ air gap
is incorporated.
DESIGN
DESIGN
SYSTEM DETAILS
TECHNICAL DATA
Water
meter
Heat
meter
District
flow
Cold
water
District
return
Programmer
F&E
Cistern
DHW
Controller
DHW
Pump
Room
thermostat
Flow sensor
Cylinder
thermostat
Back
up
immersion
heater
Diverter
Valve
(not
mid
position)
Cold
water
to
dwelling
DHW
to
dwelling
CH
flow
to
dwelling
CH
return
from
dwelling
BMS
Boilermate stainless
for
District
Heating
Coil
flow
connection
Coil
return
connection
Air
valve
Zone
valve
DHW
24
Plate
PHE
The above diagram shows the BoilerMate CP installed to a system where the pumped
supply is adequate to overcome the pressure loss of the BoilerMate CP heat exchanger
coil, the pressure loss over the central heating system components and all other
components fitted to it. In addition, all the components fitted are able to withstand
the pressure in the district system.
In the above diagram, the cold water supply to the feed and expansion cistern is not
shown, and neither is the overflow pipe which may by required if the ball valve is fitted
to the F & E cistern. See page 9 for further details. Potentially a temporary filling loop
complying with the water regulations can be installed.
Immersion Heaters
These are 3kW 240V AC heaters and incorporate a control thermostat set at 73°C and
a manually reset energy cut-out which operates at 85°C.
External wiring to the immersion heaters must be in accordance with the relevant IEE
Wiring Regulations and the circuit must be protected by a suitable fuse and a double
pole isolating switch.
The correct method of terminating the wiring to the immersion heater is shown
opposite.
BoilerMate CP
Inline filter &
flow regulator
Single check
valve
Single
check
valve
Pump isolation
valves
Cold water inlet
Plate heat exchanger
Hot water outlets
Pipework length and
diameter to suit
property demands
Pipework length and
diameter to suit
recirculation flow rate
approx 1-2 l/min
Cold water sensor
Control
stat
Flow switch
Potable water
expansion vessel
Secondary
circulation
pump
