Table Of Contents; Installation Regulations; Introduction - Worcester 24SiII Installation And Servicing Instructions

Contents
1. Installation Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
3. Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4
4. Siting the Appliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
5. Flue Terminal Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
6. Air Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
7. Sealed System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
Open Vent System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
8. Domestic Hot Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
9. Gas Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
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1. Installation Regulations

1.1 Gas Safety (Installation & Use) Regulations 1998:
The appliance is suitable for installation in GB/IE only and
should be installed in accordance with the rules in force.
It is the law in GB that a competent person in accordance with
the above regulations installs all gas appliances.
Failure to install appliances correctly could lead to prosecution.
It is in your interest, and that of safety, to ensure compliance
with the law.
1.2 The manufacturers notes must not be taken, in any way, as
overriding statutory obligations.
1.3 The compliance with a British Standard or European Norm
does not, in itself, confer immunity from legal obligations.
1.4.1 The installation of the appliance must be in accordance
with the relevant requirements of the Gas Safety Regulations,
current IEE Regulations, Building Regulations, Building Standards
(Scotland) and local water by-laws.
1.4.2 In Eire the installation must be carried out by a competent
person and installed in accordance with IS 813, Domestic Gas
Installations (Edition 2), the current building regulations and the
electrical installation must follow the ETCI rules.
1.5 The installation should follow the recommendations of the
following British Standards unless otherwise indicated.
BS5440:1 - Flues and ventilation for gas appliances: Flues
BS5440:2 - Flues and ventilation for gas appliances: Air supply.
BS5449 - Central heating for domestic premises.
BS5482 - Domestic propane gas burning installations.
BS5546:1 - Installation of gas hot water supplies.
BS6700 - Domestic water supply in buildings.
BS6798 - Installation of gas fired hot water boilers.
BS6891- Low pressure gas pipework installations upto 28mm (R1).
BS7593 - Water treatment.
BS7671 - Requirements for electrical installations.
1.6 The appliance does not contain any substances which are
harmful to health.
1.7 In certain circumstances, the installer can be held
responsible, not only for mistakes on his part but also for
damage resulting from the use of faulty materials. We advise
that, to avoid any risk, only quality approved branded fittings
are used.
1.8 LPG Installation:
The appliance shall not be installed in a room or internal space
below ground level when it is intended for use with LPG. This
does not preclude the installation into rooms, which are
basements with respect to one side of the building but open to
the ground on the opposite side.
1.9 These instructions cover, as far as possible, the foreseeable
situations, which may arise.
Contact Worcester Heat Systems Technical Department,
Telephone: 08705 266241, for advice on specific installations.
10. Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
11. Installing the Appliance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 12
12. Commissioning the Appliance . . . . . . . . . . . . . . . . . . . . Page 19
13. Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21
14. Inspection and Service . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21
15. Replacement of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 24
16. Short Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 30
17. Operational Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . Page 32
18. Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 34
19. Conversion Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . Page 42

2. Introduction

2.1 The initiative is the new code of practice to encourage
the correct installation, commissioning and servicing of domestic
central heating boilers and system equipment.
The 'Log-book' is a vital document that must be completed
by the installer at the time of installation. It confirms that the
boiler has been installed and commissioned according to the
manufacturers instructions.
A declaration of conformity (Refer to IS 813 Annex D1) must be
completed by the installer and a copy supplied to the appliance
operator for boilers installed in Eire.
Without the completion of the Log-book and/or declaration,
manufacturers may refuse to respond to a call-out from a
householder, who will be advised that he or she must call back the
installer, who has not fulfilled his obligations to record the
information required by the initiative.
Service:
To ensure continued efficient operation of the appliance it must be
checked at regular intervals. The frequency of servicing will depend
upon the particular installation conditions and usage, but once per
year should generally be adequate. The extent of the service
required by the appliance is determined by the operating condition
of the appliance when tested by fully qualified engineers.
Any service work must be carried out by competent registered
engineers (CORGI in GB).
2.2 General Information
The appliance is set to give the maximum output of 28 kW [28Si II] or
24kW [24Si II] to the domestic hot water and to the heating system.
The hot water flow rate is limited to a nominal 10 l/min [28Si II] or 8
l/min [24Si II] at a maximum temperature rise of 40°C.
The sanitary water section of the appliance is suitable for mains
water pressure of upto 10bar.
Kits are available to convert the appliance from Natural Gas to
Propane operation and vice versa.
2.3 Electrical Supply
230V - 50Hz. Load 180 watts. External fuse 3A (to BS1362),
Internal fuses F1 - 2A, F2 - 1.25A (20mm).
2.4 Gas Supply
The appliances require a maximum of 3.25 m
(G20) or 1.25 m 3 /h of propane (G31) [28Si II] or 2.8 m
natural gas (G20) or 1.08 m
The installation and the connection of the gas supply to the
appliance must be in accordance with BS6891.
The meter or regulator should deliver a dynamic pressure of 20 mbar
(G20) or 37mbar (G31) at the appliance, which is equivalent to about
19 mbar or 36 mbar at the gas valve inlet pressure test point.
2.5 Installation
The appliance is suitable for indoor installation only and for use
with a sealed system only.
Do not place anything on top of the appliance.
This is a room sealed appliance and a separate combustion air
supply is not required in any room or compartment in which the
appliance is fitted.
If the appliance is fitted in a cupboard or a compartment is built
around it after installation, then the structure must conform to the
requirements of BS6798 and BS5440 Part 2. However, because of the
low casing losses, there is no need for cooling ventilation openings in
2
3 /h of natural gas
3
/h of propane (G31) [24Si II].
3 /h of