Table Of Contents - Worcester 26CDi XTRA Installation And Servicing Instructions

Contents
1. Installation Regulations .............................................. Page 1
2. General Information .................................................... Page 1
3. Technical Data .............................................................. Page 4
4. Siting the Appliance .................................................... Page 6
5. Siting the Flue Terminal .............................................. Page 8
6. Air Supply .................................................................... Page 8
7. Sealed Primary Systems ............................................ Page 9
8. Domestic Hot Water ....................................................Page 10
9. Electrical ........................................................................Page 10
1. Installation Requirements
1.1 Gas Safety (Installation and Use) Regulations 1998,
as amended, all gas appliances must be installed by a
competent person in accordance with the above regulations.
Failure to install appliances correctly could lead to prosecution.
1.2 The manufacturer's notes must not be taken, in any way, as
overriding statutory obligations.
1.3 The compliance with a British Standard does not, of itself,
confer immunity from legal obligations. In particular the
installation of this appliance must be in accordance with the
relevant requirements of the Gas Safety (Installation and Use)
Regulations 1998 as amended, current IEE Wiring Regulations BS
7671, local Building Regulations, Building Standards (Scotland)
(Consolidation) and bylaws of the local Water Company. Health
and Safety Document No. 635 (Electricity at Work Regulations). It
should be in accordance with the relevant recommendations of
the following British Standards:
BS 6798:1987 Specification for installation of gas fired hot water
boilers of rated input not exceeding 60 kW.
BS 5449:1990 Central Heating for Domestic Premises.
BS 5546:1990 Installation of gas hot water supplies for domestic
purposes.
BS 5440:1:1990 Flues and Ventilation for gas appliances of rated
input not exceeding 60 kW: Flues.
BS 5440:2:1989 Flues and Ventilation for gas appliances of rated
input not exceeding 60 kW: Air Supply.
BS 6891:1988 Installation of low pressure gas pipework
installations up to 28mm (R1).
BS 5482:1:1994 & 2:1997 Installation of LPG appliances.
1.4 To ensure that the installation will perform to the highest
standards, the system and components should conform to any
other relevant British Standards in addition to those mentioned
in the instructions.
1.5 The boiler section contained within this appliance is a
condensing boiler. When in use, the boiler will operate at high
efficiency, emitting a white plume of condensation from the flue
terminal.
A condensate drain point is provided on the appliance.
1.6 The advice and instructions given in this document covers,
as far as possible, the foreseeable situations which may arise.
Contact Worcester Heat Systems for advice on specific
installations.
10. Installation.................................................................... Page 14
11. Commissioning ............................................................ Page 19
12. Instructions to the User .............................................. Page 22
13. Inspection and Servicing ............................................ Page 23
14. Replacement of Parts .................................................. Page 25
15. Short Parts List ............................................................ Page 34
16. Operational Flow Diagrams........................................ Page 36
17. Fault Finding ................................................................ Page 39
2. General Information
2.1 This appliance is not suitable for external installation
2.2 The appliance controls are set to provide a maximum output
of 26.0 kW in the condensing mode and 24.0 kW in the non-
condensing mode for the domestic hot water and central heating
load.
2.3 The control circuit provides direct burner ignition. A pilot
light is not used.
2.4 PRINCIPAL APPLIANCE COMPONENTS
See fig. 1.
Fig. 1. Appliance water flow diagram.
Automatic
Air Vent
Circulating
Pump
Water to Water
Heat Exchanger
Water Diverter
Valve
CH Flow
Domestic
Hot Water
Out
A low thermal capacity gas to water main heat exchanger
connected to a secondary high efficiency heat exchanger.
A water to water heat exchanger to provide domestic hot water.
Fully modulating controls in the central heating and domestic
hot water modes of operation.
2
Secondary
High
Efficiency
Heat
Exchanger
Gas to Water
Heat
Boiler
Exachanger
Expansion
Vessel
Pressure
Relief
Valve
Central Heating
By-pass
Adjustment
Condensate
Drain
Valve
Discharge
Domestic CH Return
Relief
Cold Supply