Technical data

1919
Cold water connection
Wherever possible the cold supply to the appliance should
be the first connection off the mains supply, in order to
minimise hot water flow reduction when cold water services
are operated. The final 600mm of piping to the appliance
should be of copper only.
Cold water pressure
To achieve the stipulated flow rates of 20l/min (4.4gpm)/
25l/min (5.5gpm) a working cold water mains pressure of
1.5bar/1.7bar is required. The appliance will operate at a
minimum working pressure of only 0.5bar (7.5psi), however
a reduced hot water flow rate should be expected.
Back-flow prevention devices, including water meters,
can prevent the expansion of hot water into the cold
water main. However, this can result in a pressure build-up
that may cause damage to the boiler and household
devices such as showers, washing machines etc. In
these cases we recommend that a mini-expansion vessel
(Part No. 7 716 192 105) be fitted adjacent to the boiler in
the cold water main.
Hot water supply
As with all mains fed systems, the flow rate of water
obtainable from individual taps will vary in relation to the
number of taps operating simultaneously, and will depend
upon the cold mains supply available to the property.
Therefore, in order to avoid excessive starvation of flow
to individual taps, flow balancing may be required by the
use of proprietary constant volume flow regulators or
Ball-o-Fix valves.
Hot water systems
Taps and valves
Hot and cold taps and mixing valves used with Greenstar
Highflow CDi appliances must be suitable for operating at a
mains pressure of up to 10bar (150psi) and temperatures of
65°C (150°F).
Showers
When a loose head shower with a flexible hose is used
over a bath or shower tray, the hose must be fixed so that
the head cannot fall closer than 25mm (1in) above the top
edge of the spill over level of the relevant bath or shower
tray. Alternatively, the feed pipes to the shower should
incorporate a double check valve assembly or a check valve
and vacuum breaker.
With fixed head showers no provision is necessary.
The use of a thermostatically controlled shower will give
added comfort and safeguard against high hot water
temperatures.
Bidet
The supply of hot and cold water mains direct to a bidet
is permitted provided that the bidet is of the overrim
water feed type. The outlet(s) should be shrouded and
not have any temporary hand held spray attached. No
other anti-siphonage arrangements are necessary.
Use in hard water areas
As the maximum temperature of the domestic hot water heat
exchanger is limited by the electronic control circuit, there
is normally no need for water treatment to prevent scale
accumulation.
In areas where exceptional water conditions prevail,
consideration may need to be given to the fitting of a device
capable of preventing scale. In such circumstances the
advice of the local water authority should be sought.
Guarantee
Worcester Greenstar combi appliances are offered with a
full 5 year guarantee* on parts and labour and a 10 year
guarantee* on the primary heat exchanger*. Ongoing service
and maintenance contracts can be arranged through the
Worcester Customer Service Department.
Please contact our guarantee
registration advisors on
0330 123 2552 or visit
www.worcester-bosch.co.uk/
guarantee
D
C
A
B
MAINS WATER EXPANSION VESSEL:
A - Mini expansion vessel, Part No. 7 716 192 105
B - Mains water inlet pipe
C - Non-return valve
D - Boiler
*Subject to terms and conditions.
On all Greenstar
combi appliances*
On the primary
heat exchanger*