Table Of Contents; Installation Regulations; Introduction - Worcester 25Si Installation And Servicing Instructions

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

1. Installation Regulations

1.1 Gas Safety (Installation & Use) Regulations 1998.
It is the law that all gas appliances are installed by a competent
person in accordance with the above regulations. 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 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 bye-laws.
1.5 The installation should follow the recommendations of the
following British Standards unless otherwise indicated and to
any other relevant standards.
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 (when relevant).
BS6798 - Installation of gas fired hot water boilers.
BS6891 - Low pressure gas pipework installations up to 28mm
(R1).
BS7593 - Water treatment.
1.6 The appliance and/or components must conform, where
applicable, to all relevant Directives.
1.7 In accordance with COSSH the appliance does not contain
any substances which are harmful to health.
1.8 Product Liability regulations indicate that, 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.
1.9 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.
1.10 These instructions cover, as far as possible, the foreseeable
situations which may arise. Contact Worcester Heat Systems
Technical Department, Telephone: 0990 266241, for advice on
specific installations.
9. Gas Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
10. Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
11. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 12
12. Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 18
13. Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 20
14. Inspection and Servicing . . . . . . . . . . . . . . . . . . . . . . . . . Page 20
15. Replacement of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 22
16. Short Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 28
17. Operational Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . Page 30
18. Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 32

2. Introduction

The Benchmark 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.
Without the completion of the Log-book, 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.
It is important that:
The services and the system are properly flushed as specified.
The User is clearly instructed on the correct operation of the appliance.
The benefits of regular servicing are explained - to maintain the
efficiency and extend the life of the appliance.
2.1 General Information
The appliance is set to give the maximum output of 28 kW [28Si]
or 25kW [25Si] to the domestic hot water and to the heating
system. The hot water flow rate is limited to a nominal 10 l/min
[28Si] or 9 l/min [25Si] 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.
2.2 Electrical Supply
230V - 50Hz. Load 180 watts. External fuse 3A, Internal fuses F1
- 2A, F2 - 1.6A (20mm).
2.3 Gas Supply
The appliances require a maximum of 3.38 m
3
(G20) or 1.25 m /h of propane (G31) [28Si] or 2.98 m
natural gas (G20) or 1.12 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
18.5 mbar or 36 mbar at the gas valve inlet pressure test point.
2.4 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.
It 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 not a need for the
cooling ventilation openings in the compartment. The spaces
specified in Section 6. Air Supply must be provided.
There is space for the service pipes to pass at the back of the appliance.
2.5 Flue
The flue can be to the right, left or rear. A vertical flue system is available.
The flue terminal, on the outside wall, must not be obstructed or damaged.
An internal flue fitting kit is available. Fitting instructions are
given in Section 11.9.
2
3 /h of natural gas
3
/h of propane (G31) [25Si].
3
/h of