Technical data

1918
Propane gas supply
The Greenstar Si Series is available in a propane gas version. The
appliance when on a hot water or full output demand will require up to
2.38 kg/h of gas (depending on the model). The gas tank or bottles
must be capable of supplying this quantity of gas at a nominal
pressure of 37mbar (14.8in wg) at the appliance. The table below
shows the propane gas discharge through varying lengths of pipe
and the resistance to flow created by elbows, bends etc. Pipework
should be sized to overcome this resistance.
Approximate Additional Length to be Allowed (LPG)
Electricity supply
A 3amp fused three pin plug and unswitched shuttered socket
outlet (both complying with BS 1362) or preferably a double pole
isolator with a contact separation of 3mm in all poles supplying the
appliance should be used.
The appliance electrical circuits are also protected by an internal
2amp fuse. The appliance must be earthed.
Mains cold water supply
Water Authority requirement
A direct mains cold water connection is permitted by Water
Authorities. However, it is recommended that reference be made to
local requirements. In the event of difficulty contact Worcester
Bosch Technical Department.
Pipe sizing
Unless the mains pressure is low, a standard 15mm diameter
service pipe is normally suitable. A 15mm hot water distribution pipe
to the first branch is recommended thereafter 15mm and/or 10mm
to all draw off points.
Cold water connection
Connection should be made as shown in the pipework detail and
the appliance installed generally in accordance with the layout
shown on page 10.
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 rate a working cold water mains
pressure of 1.3bar is required. The appliance will operate at a
minimum working pressure of only 0.2bar (3psi) however a reduced
hot water flow rate should be expected. Where back-flow prevention
devices, including water meters, are fitted the expansion of hot
water into the cold water main can be prevented. 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
A domestic hot water flow regulator, set to give an optimum flow
rate of 9.8 or 11.4lts/min ±15% (dependent on model) is fitted to
the cold supply of the hot water heat exchanger.
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.
369
1.5 1.01 – 15
8.0 5.2 4.2 22
15.9 8.9 8.3 28
Total length of Gas Supply Pipe (metres)
Pipe
Diameter
(mm)
Gas Discharge
Rate m
3
/h
Elbows or Tees 90º Bends
Metres Feet Metres Feet
0.6 2 0.3 1
Hot water systems
Taps and valves
Hot and cold taps and mixing valves used with the Greenstar Si
Series appliance must be suitable for operating at a mains pressure
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.
Alternatively, a pressure balancing shower valve specifically
designed for constant temperature water heaters would be suitable.
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 to have any temporary
hand held spray attached. No other anti-syphonage 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.
Warranty
Worcester Bosch Greenstar Si appliances are offered with a full 2
year guarantee* on parts and labour. Ongoing service may be
arranged through the Worcester Bosch Customer Service
Department.
*Subject to conditions.
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