Worcester 440CDi Wartungshandbuch PDF herunterladen (Seite 15)

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Natural gas supply

Appliances, when on a full output demand, will require up

to 3.1m

/hr of gas for the 440CDi and 4.4m

/hr of gas for

the 550CDi. 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 that of the appliance inlet connection.

The meter outlet should be capable of ensuring a nominal

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.

Elbows or tees

Metres Feet

0.50 2

90º bends

Metres Feet

0.3 1

Approximate additional length to be allowed (natural gas)

Liquid Petroleum Gas (LPG) supply

An LPG kit is an available accessory for Greenstar Highflow

CDi combis. The appliances, when on a ho

t water or full

output demand, will require up to 2.3kg/hr of gas for the

440CDi and 3.2kg/hr of gas for the 550CDi. 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 LPG discharge through varying

lengths of pipe and the resistance to flow created by

elbows, bends etc. Pipework should be sized so as to

overcome this resistance.

MAINS WATER EXPANSION VESSEL:

A - Mini e

xpansion vessel, Part No. 7 716 192 105

B - Mains water inlet pipe

C - Non-return valve

D - Boiler

Electricity supply

A 3amp fused three pin plug and unswitched shuttered

socket outlet (both complying with BS 1363) 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 2.5amp 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 the Worcester Technical Support Department.

Pipe sizing

Unless the mains pressure is low, a standard 22mm

diameter service pipe is normally suitable. A 22mm hot

water distribution pipe to the first branch is recommended

thereafter 15mm and/or 10mm to all draw off points.

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.

Total length of Pipe diameter

gas supply pipe (m) (mm)

369 –

Gas 2.9 – – 15

discharge

8.7 5.8 4.6 22

rate m

18.0 12.0 9.4 28

Elbows or tees

Metres Feet

0.6 2

90º bends

Metres Feet

0.3 1

Approximate additional length to be allowed (LPG)

Total length of Pipe diameter

gas supply pipe (m) (mm)

369 –

Gas discharge 8.0 5.2 4.2 22

rate m

/h 15.9 8.8 8.3 28

Installation requirements

Installation of Greenstar Highflow CDi combis must be in

accordance with the relevant requirements of the Gas

Safety (Installation Use) Regulations at the time of

installation, current IEE Wiring Regulations, local Building

Regulations, Building Standards (Scotland) 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 Gas Safe 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 Greenstar Highflow CDi combis are supplied

com

plete with all the necessary components to form a

sealed primary system. Included are a pre-plumbed

expansion vessel (12 litres), a pressure relief valve (set at

3bar), an automatic air vent and a pressure gauge.

The expansion vessel fitted to the appliance will

accommodate differing system volumes, depending upon

its initial charge pressure, and system pre-pressurisation.

The table below shows the system volume that can be

accommodated under different conditions. If it is found

that the system volume exceeds that catered for by the

expansion vessel fitted within the appliance, then an extra

vessel should be added as close to the appliance as

possible in the heating return pipe. Refer to BS 5449:1

and BS 6798:1 for further information.

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 a test point fitted to the mains water side of

the temporary circuit. This is supplied within the boiler.

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.

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 copper.

Open vented primary systems

It is not permissible to install a Greenstar Highflow CDi

combi on an open v

ent system.

Total system volume – litres (gallons)

Initial system Initial charge pressure (bar)

pressure (bar) 0.5 1.0 1.5

0.5 130 (29) – –

1.0 80 (17.5) 102 (22.5) –

1.5 43 (9.5) 58 (13) 71 (15.5)

2.0 20 (4.5) 27 (5.9) 33 (7.5)

1 2 ... 10 11 12 13 14 15 16 17 18 19

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