Technical data

1716
Installation of the Greenstar Si Series must be in accordance with
the relevant requirements of the Gas Safety (Installation Use)
Regulations (as amended), current IEE Wiring Regulations, local
Building Regulations, Building Standards (Scotland) (Consolidation)
regulations and bylaws of the local Water company and Health and
Safety Document No. 635 (Electricity at Work Regulations 1989). It
should be in accordance with the relevant recommendations of the
following British Standards:
BS 6798; BS 5449; BS 5546:1; BS 5440:1; BS 5440:2;
BS 6891.
Gas Safety (Installation and Use) Regulations. All gas appliances
must be installed by a Corgi registered person in accordance with
the above regulations. Failure to install appliances correctly could
lead to prosecution.
The manufacturers notes must not be taken in any way as
overriding statutory regulations.
Sealed primary systems
Worcester Bosch Greenstar Si combi boilers are supplied complete
with all the necessary components to form a sealed primary system.
Included are a pre-plumbed expansion vessel, a pressure relief valve
(set at 3bar), an automatic air vent and a pressure gauge.
With an initial system pressure of 0.5bar a system capacity
of approximately 83 litres can be accommodated. Refer to
BS 7074:Part 1 for more information. The charge pressure can
be increased by with a decrease in system volume.
It is important with an Aluminium Heat Exchanger that the pH level
of the water does not exceed 8. Levels in excess of this could be
detrimental to the Heat Exchanger.
The use of a suitable inhibitor will provide a resistance to this.
Contact Betz Dearborn (Tel: [phone]) or
Fernox (Tel: [phone]) for further details.
System filling and make-up
To comply with the Water Authority requirements, the system should
be filled via a temporary hose connection to the mains cold water
supply, with a double check valve assembly and test point fitted to
the mains water side of a temporary circuit. Alternatively the plug in
filling loop option (part number 7 716 192 281, see page 20 for
photograph), simply connects between the cold main connection
and the heating return circuit on the wall mounting jig.
Valves and joints
It is very important that all valves and joints are able to sustain a
working pressure of up to 3bar (45psi). Particular care should be
exercised when fitting radiator valves and only those of high quality
to BS 2767:10 should be used. All other valves and fittings should
comply with BS 1010.
Loss of water pressure from a sealed system will require continuous
recharging with fresh water and consequential introduction of air. Air
is highly corrosive and will considerably reduce life expectancy of
radiators, pumps etc.
Installation requirements
Plastic pipework
The use of plastic pipework is acceptable. However, some plastics
are permeable to oxygen and must be avoided. Only pipework with
a polymeric barrier should be used. Please note that the first
600mm of pipework connected to the boiler must be of copper or
steel.
Natural gas supply
The appliances when on a hot water or full output demand will
require up to 3.24m
3
/hr of gas (depending on the model). The gas
meter and supply pipes must be capable of supplying this quantity
of gas in addition to the demand from any other appliance being
served. It is important that a gas supply pipe of at least 22mm
diameter is used. Under no circumstances should the size of the
gas supply pipe be less than that of the appliance inlet connection.
The meter outlet governor should be capable of ensuring a dynamic
pressure of 20mbar (8in wg) at the appliance. Particular
consideration should be given to the resistance to gas flow created
by elbows, bends etc. Pipework should be sized to overcome this
resistance, details of this are given in the table below.
Approximate Additional Length to be Allowed (Natural gas)
Elbows or Tees 90º Bends
Metres Feet Metres Feet
0.5 2 0.3 1
369
2.9 – – 15
8.7 5.8 4.6 22
18.0 12.0 9.4 28
Total length of Gas Supply Pipe (metres)
Pipe
Diameter
(mm)
Gas Discharge
Rate m
3
/h
Option 2
VERTICAL BALANCED FLUE SYSTEM WITH TWO
45° BENDS
Flue Components Required
25 & 30Si Models
Flue Diameter Description Quantity Worcester Bosch Part No.
100mm Vertical Flue Kit 1 7 719 002 430
100mm Extension Flue Kit 4 7 719 002 349
100mm 45˚ Elbow (pack of 2) 2 7 719 002 347
125mm Vertical Flue Kit 1 7 719 002 431
125mm Extension Flue Kit 13 7 719 001 892
125mm 45˚ Elbow (pack of 2) 2 7 719 001 899
Maximum total straight flue length
100mm 125mm
25 & 30Si 4,400mm 13,000mm
Option 3
VERTICAL BALANCED FLUE SYSTEM WITH TWO
90° BENDS
Flue Components Required
25 & 30Si Models
Flue Diameter Description Quantity Worcester Bosch Part No.
100mm Vertical Flue Kit 1 7 719 002 430
100mm Extension Flue Kit 2 7 719 002 349
100mm 90˚ Elbow 2 7 719 002 347
125mm Vertical Flue Kit 1 7 719 002 431
125mm Extension Flue Kit 11 7 719 001 892
125mm 90˚ Elbow 2 7 719 001 899
Maximum total straight flue length
100mm 125mm
25 & 30Si 2,400mm 11,000mm