System Fill - Bosch Worcester Greenstar 8000 Series Installation And Maintenance Instructions Manual

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Fig. 9 Example layout - Internal diverter valve kit
[1] Appliance with internal diverter valve kit
[3] Unvented hot water cylinder
Unvented cylinders
In all cases the cylinder manufacturer must be contacted for
confirmation their product is suitable for the installation layout shown in
figure 9.
Although the accepted common practice of a 2-port motorised valve
installed in the primary flow pipe to the cylinder and wired to the dual-
thermostat supplied with the cylinder. It is possible to use the integral
diverter valve kit and not need the 2-port motorised valve to cut the flow
of heat to the cylinder to comply with Building Regulation Part G3.
• The integral diverter valve kit cylinder sensor must be used.
• The general layout (figure 9) can be used for unvented cylinder by
utilising the high limit thermal cut out of the cylinder dual-thermostat
to interrupt the permanent live to the appliance, preventing any heat
being produced from the appliance.
Example layout with unvented cylinder & cylinder safety valve.
If required by the cylinder manufacture to fit/use the cylinder safety valve
then this can also be carried out (figure 10) with the integral diverter
valve kit.
• The cylinder safety valve and dual-thermostat (control thermostat
and high limit thermal cut out) are wired to interrupt the permanent
live to the appliance, preventing any heat being produced from the
appliance.
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Fig. 10 Example layout - Internal diverter valve kit with unvented
cylinder and cylinder safety valve
[1] Appliance with internal diverter valve kit
[2] Cylinder safety valve (unvented cylinder)
[3] Unvented hot water cylinder
Greenstar 8000 Style – 6720883855 (2019/01)
4.1.4

System fill

Filling primary sealed systems
NOTICE:
Filling the primary sealed system
The system must not be filled with salt based softened water.
▶ Ensure the primary water filling point uses an untreated cold water
connection from the mains supply, before a water softener.
• Filling the system must comply with one of the following methods
shown.
• The filling point must be at low level and must never be a permanent
connection to the mains water supply.
• Filling loops must be WRAS approved.
• If the external filling link is sited away from the appliance, then a
pressure gauge should be installed at the filling point.
External filling loop
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Fig. 11 External filling loop system fill example
[1] Cold mains inlet pipe
[2] Stop valve
[3] Check valve
[4] Test point
[5] Hose union
[6] Central heating flow pipe
Top-up tank system fill
In situations where the cold mains pressure is not sufficient to pressurise
the system to between 1 and 1.5bar an alternative can be to use a top-up
tank.
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Fig. 12 Top-up tank system fill example
[2] Stop valve
[3] Check valve
[6] Central heating flow pipe
[7] Top-up tank
[8] Automatic air vent
[9] Minimum height above the highest point of the system - 1000mm
(39 in)
Pre-Installation
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