Worcester 26CDi Xtra User manual

26CDi XTRA
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
G. C. NUMBERS.
NATURAL GAS. L. P. G.
47 311 41 47 311 42
IMPORTANT: THIS APPLIANCE IS FOR USE WITH NATURAL GAS OR LPG.
THESE INSTRUCTIONS APPLY IN THE UK ONLY.
THESE INSTRUCTIONS ARE TO BE LEFT WITH THE USER OR AT THE GAS METER
26CDi XTRA

EXCELLENCE COMES
AS STANDARD
Thank you for purchasing the Worcester 26CDi Xtra gas-
fired combination appliance.
Worcester 26CDi Xtra appliances are made by Worcester
Heat Systems and the strictest quality control standards are
demanded throughout every stage of production.
Indeed, Worcester Heat Systems have led the field in
innovative appliance
design and performance
for more than 30 years.
The result is that your
new Worcester 26CDi Xtra
appliance offers you the
very best of everything -
quality, efficiency,
economical running costs,
proven reliability and
value for money.
What’s more, you also
have the assurance of our
no-nonsense 1 year parts
and labour guarantee.
And, to keep your boiler operating at peak condition and
efficiency, an optional maintenence scheme is available from
Worcester Heat Systems Ltd. Contact our Service Contracts Team
on 01905 754624 for further details.
Page No.
Operating Instructions
.................................... 3-11
Fault and Breakdowns 12
Maintenance and
Extended Warranty
Information ............ 13-14
Guarantee Details ... 15-16
CONTENTS
2

GENERAL
INFORMATION
GAS SAFETY (INSTALLATION AND USE)
REGULATIONS 1998
It is the law that 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. It is in your interest and that of safety to ensure compliance
with the law. The manufacturers notes must not be taken, in any way, as overriding
statutory obligations.
WARNING: This appliance must be earthed and protected by a 3 amp fuse.
ELECTRICITY SUPPLY: 230V ~ 50Hz
IMPORTANT: To get the best from your Worcester 26CDi Xtra please read
these instructions carefully.
NOTE: In the event of a fault the appliance should not be used until the fault
has been corrected by a competent person.
BENCHMARK
The Benchmark initiative is a code of practice to encourage the correct
installation, commissioning and servicing of domestic central heating boilers and
system equipment.
A 'log book' is dispatched with every appliance, This is a vital document
that needs to 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.
All CORGI Registered Installers carry a CORGI ID card and have a
registration number. Both should be recorded in your central heating log book. You
can check that your installer is CORGI registered by calling CORGI on 01256 372300.
Without the completion of the log book, manufacturers may refuse to
respond to a call-out request. It is important that your installer has given you the
fully completed log book.
GENERAL DESCRIPTION
(See Fig.1.)
The WORCESTER 26CDi Xtra is a condensing, combined domestic hot water
and central heating appliance. It consists of a gas fired boiler with a secondary, high
efficient heat exchanger, having a varying output of between 6.7 kW and 26 kW. A
water to water heat exchanger to provide domestic hot water via the boiler,
circulating pump and water diverting valve. All the necessary controls to provide
mains fed domestic hot water and central heating.
The appliances are supplied as standard with a manual operating
switch. Alternatively a facia mounted programmer may have been fitted.
The appliance can operate in one of two modes. Hot water only or hot water
and central heating.
PLUMING: Because the appliance operates at high efficiency a white
plume of condensate will be emitted from the flue terminal which is fitted
outside the dwelling. The pluming will be more noticeable during cooler weather
and will occur every time the appliance is used.
Hot Water Mode:
When a demand is made for hot water by opening a tap or shower, the flow
switch will energise the pump and circulate primary hot water around the boiler and
water to water heat exchanger. The burner will light at its maximum setting.
When hot water is no longer required the appliance pump and fan may
continue to operate to dissipate the residual heat within the boiler.
A flow restrictor is fitted within the appliance which limits a hot water
delivery rate to a maximum of 9.0 (±15%) litres/minute (2.0 gallons/minute). 3

4
Hot Water and Central Heating mode:
When a demand is made for heating by the system controls (i.e. a
programmer or room thermostat). the pump will energise circulating
primary water around the heating system and the burner will light.
The heat output from the appliance in this mode has been factory set
to maximum. The appliance will operate as necessary to maintain the
temperature of the radiators at the level set by the adjustment of the
Heating Temperature Control Knob. (See Fig. 3.)
If the system no longer requires output to maintain the desired
room temperature, the burner will extinguish. The pump will
continue to run for a short
period to dissipate the
residual heat from the
appliance and then switch off.
The pump will run for
the duration of the demand
and only shut off if the room
thermostat or programmer is
satisfied.
The appliance will supply
heat to the central heating
system as required. A demand
for hot water at a tap or
shower will override the
central heating function for
the period of the domestic hot
water demand.
NOTE: If in doubt about
the use of the controls ask
your installer to assist you.
Fig. 1. Appliance Water Flow Diagram.
Secondary Heat
Exchanger
Automatic
Air Vent
Circulating
Pump
Water To Water
Heat Exchanger
Water Diverter
Valve
Pressure Relief
Valve
Condensate
Drain
Safety
Relief
CH
Return
CH
Flow
Domestic Cold
Water Supply
Domestic Hot
Water Out
Gas To Water
Heat Exchanger
Boiler
Expansion
Vessel

5
CENTRAL HEATING SYSTEM
During the first few hours of operation of the central heating
system, check that all radiators are being heated at an even rate.
Should the upper area of a radiator be at a lower temperature than the
base of the radiator, it should be vented by releasing air through the
venting screw at the top of each radiator. Make sure your installer
shows you how to carry out the operation. Repeated venting will
reduce the quantity of water in the system and this must be
replenished for safe and satisfactory operation of the appliance.
Should water leaks be found in the system or excessive venting be
required from any radiator, your installer or heating engineer should
be contacted and the system corrected.
SEALED HEATING SYSTEM
The appliance will be fitted to a sealed heating
system which is pre-pressurised. Your installer will
advise you on the minimum and maximum pressure that
should be indicated on the pressure gauge. See Fig. 3.
Check regularly that this pressure is maintained and
contact your installer or maintenance engineer if there is
a permanent significant drop in pressure indicated on
the gauge. If the system loses pressure it should be re-
pressurised as instructed by the installer (N.B. Maximum
pressure 2.5 bar).
Pressurising The System (See Fig. 2).
(If in doubt leave this procedure to your installer).
Remove the bottom panel to gain access to the
filling loop assembly.
Insert the bayonet end of the filling key into the
corresponding cut outs in the filling loop housing and
twist to lock the key in place.
Turn the grey knob anti-clockwise to allow water
ingress and fill until the required pressure is reached.
Turn the grey knob clockwise to stop filling and
remove. Remove the filling key by lining up the bayonet
end of the key with the cut outs in the filling loop
housing and withdrawing the key.
N.B. The key must always be removed from the
filling loop housing after the system has been filled to
prevent accidental filling and to comply with Bylaw 14
of the Water Bylaws Scheme.
Store the key in a safe place for future use and refit
the bottom panel.
GENERAL NOTES
Fig. 2.
Grey
Knob
Filling Key

6
CLEARANCES
Your installer will have
provided adequate space around
the appliance for safety and
servicing. Do not restrict this
space by the addition of
cupboards, shelves etc. close to
the appliance.
Minimum clearances in
millimetres.
ROOM THERMOSTAT
A room thermostat may be fitted for control of the central heating
temperature. It will be located in one room of the home. The method
of setting a room thermostat varies with the type and manufacture.
Refer to the instructions supplied with the room thermostat.
THERMOSTATIC RADIATOR VALVES
If thermostatic radiator valves are to be fitted to the system then
they must conform to the requirements of BS2767:10. It is advisable to
leave one valve permanently set at maximum to prevent the boiler
short cycling.
SHOWERS, BIDETS, TAPS AND MIXING
VALVES
Standard hot and cold taps and mixing valves used with the
appliance must be suitable for operating at mains pressure.
Thermostatically controlled shower valves will guard against the flow
of water at too high a temperature.
If using a pressure equalising valve, set the Domestic Hot Water
temperature control knob to the ‘MAX’ position.
Hot and cold mains fed water can be supplied direct to an
overrim flushing bidet subject to local water company requirements.
With all mains fed systems the flow of water from the individual
taps will vary with the number of outlets operated simultaneously
and the cold water mains supply pressure to the property. Flow
balancing using ‘Ball-o-Fix’ type valves is recommended to avoid an
excessive reduction in flow to individual outlets.
For further information contact Worcester Heat Systems
Technical Helpline.
HOT AND COLD FLOW
If the flow of water demanded from both hot and cold service
outlets is dependent upon mains supply, it may not be possible in
some installations to operate all outlets simultaneously.
WATER MAINS FAILURE
It is important to note that in the event of a mains water supply
failure, no tap water will be available until the mains supply is
restored. The appliance can still be used for heating because it is fitted
to a sealed system.
USE IN HARD WATER AREAS
Normally there is no need for scale protection. However, in areas
of exceptionally hard water supply it is recommended that an In-Line
scale inhibitor be fitted.
Installation should be strictly in accordance with the
requirements of the local Water Company. An isolating valve to
facilitate servicing should be incorporated.
The water hardness may be determined using the standard test
paper or by reference to the local Water Company.
Further information may be obtained from Worcester Heat
Systems Technical Helpline.
POSITION CLEARANCE
Left-hand side 10
Right-hand side 10
In Front 600
Above 180
Below 200

7
VENTILATION OF ROOM SEALED FANNED
FLUE (RSF) APPLIANCES
This is a room sealed appliance and any ventilation openings in a
wall or door must not be obstructed. Do not allow the flue terminal
fitted on the outside wall to become obstructed or damaged.
NOTE: Do not place anything on top of the appliance. If the
appliance is fitted in a compartment do not use the compartment for
storage purposes unless it conforms to the requirements of
BS 6798:1987: Section 6. It is essential that the airing space is
separated from the boiler space by a perforated non-combustible
partition as described in BS 6798:1987.
CIRCULATING PUMP
This may be fitted with a speed adjuster. If so it will be factory
set at maximum and should not be changed.
FROST PRECAUTIONS
If the appliance is not to be used for a long period of time and
there is a likelihood of freezing, then the appliance should be drained.
The Worcester Heat Systems Technical Helpline will advise you on
suitable frost precautions. For short periods the built-in frost
protection of the appliance will be adequate.
SERVICE
Annual servicing is important in order to ensure continuing high
efficiency and long life for your appliance. In the event of any
difficulty in making suitable servicing arrangements, Worcester Heat
Systems Limited or other competent persons will be happy to discuss
regular servicing arrangements and offer a comprehensive
maintenance contract.
WARNING
If a gas leak exists, or is suspected, turn off the gas supply to the
appliance at the service cock and consult your local service engineer.
Do not touch any electrical switches to turn them either on or off.
Open all windows and doors. Do not smoke. Extinguish all naked lights.
CLEANING
Do not use abrasive cleaners on the outer casing. Use a damp
cloth and a little detergent.
CONDENSATE DRAIN
Your installer will have provided a plastic condensate drain pipe
from the appliance.
The pipe should discharge into the household drainage system,
outside gully or soak away.

8
OPERATION OF
CONTROLS
(See also label on inside of appliance front cover).
The appliance is fitted with the following controls:
See fig. 3.
OPERATING SWITCH
In the ‘0’position there is no mains electricity to the
appliance.
In the ‘I’ position mains electricity is connected to the
appliance.
CENTRAL HEATING TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered to the radiators between the ‘I’ and ‘MAX’ position.
When the knob is turned anti-clockwise past the ‘I’ position towards
the ‘’(Summer Position), then the appliance will operate in the
HOT WATER mode only and no heat will be delivered to the radiators.
DOMESTIC HOT WATER TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered at the domestic hot water taps between the ‘0’ and
the ‘MAX’ position.
By slightly reducing the flow of domestic water from the tap, the
delivery temperature of the water will be further increased. This is of
particular advantage in the winter, for example to increase bath water
temperature. Also this will provide an added advantage of reducing
the delay before hot water is obtained.
FACIA MOUNTED PROGRAMMER (if fitted)
Your installer may have mounted either a mechanical or an
electronic programmer into the facia of your appliance. Operating
instructions are supplied with the programmer.
RESET BUTTON
Press this button in for five seconds if any of the indicator lights
are flashing.
SYSTEM PRESSURE GAUGE
The red needle has been set to show the sealed system pressure
which is required for the appliance to operate effectively. The grey
needle will show the actual pressure in the system.

9
INDICATOR LIGHTS
Mains electricity indicator:
OFF : No mains electricity to the appliance
ON : Mains electricity is connected to the
appliance
Central heating demand indicator:
OFF :No demand for heat to the central
heating circuit
ON :Central heating demand
FLASHING SLOW : Ignition lockout
(once per second)
FLASHING FAST : Appliance fault (other than ignition
(five times per second) lockout)
Domestic hot water demand indicator:
OFF :No demand for domestic hot water
ON : Domestic hot water demand
FLASHING FAST :Air flow fault.
(five times per second)
Central heating and domestic hot water demand indicators:
BOTH FLASHING SLOW :Overheat cut-off
(once per second)
Flame detection indicator:
OFF :Burner off
ON :Burner on
Fig. 3. Controls.
Operating
switch
Mains
electricity
indicator
Reset
button
Flame detection
indicator
DHW demand
indicator
Central heating
demand indicator
CH temp
control knob
DHW temp
control knob
System pressure
gauge
26CDi XTRA

10
TO LIGHT THE APPLIANCE
Check that the water valves to the central heating circuit are open.
Check that the grey needle on the pressure gauge is not below
the required pressure.
Switch on the mains electricity. The green power on indicator
will light. Set the room thermostat, if fitted, to maximum. Turn the
central heating temperature control knob to ‘MAX’. The red central
heating demand indicator will light.
The burner will light and the red flame detection indicator will light.
Set the central heating and hot water temperature control knobs
and the room thermostat, if fitted, to the desired temperature.
TO STOP THE APPLIANCE
For Short Periods
Turn the central heating temperature control knob fully anti-
clockwise to the ‘O’ position.
For Long Periods
Turn the operating switch to the ‘O’ position. Switch off the
mains electricity.
A facia mounted electronic programmer will retain its settings for
about two weeks, after which it will return to the factory set
programme. The display will disappear
after approximately 12 hours.
A facia mounted mechanical
programmer will require resetting once
the operating switch has been set to ‘O’,
or the mains supply has been
disconnected.
ELECTRICITY SUPPLY
FAILURE
If the electricity supply fails the
appliance will not operate. Once the
supply is restored the appliance will
return to normal operation. If a
programmer is fitted, check that the
settings have been maintained.
OVERHEAT CUT-OFF
THERMOSTAT
The appliance will enter a lockout
condition in the event of overheating.
An overheat cut-off thermostat is
fitted to the appliance which will
interrupt the electricity supply to the
gas valve.
If the overheat cut-off has
operated, both the central heating and
the hot water demand indicators will
flash together.
Fig. 4. 26CDi Xtra with front panel removed.
Circulating pump
Clip
Locating peg
Expansion
vessel
Gas valve
TO LIGHT AND STOP THE
APPLIANCE

11
The appliance can be reset by pressing the reset button and
holding in for 5 seconds.
IGNITION LOCKOUT
The appliance will enter a lockout condition in the event of the
burner failing to ignite.
If the burner fails to light within a preset time of 10 seconds the
electricity supply to the gas valve will be interrupted.
If ignition lockout has occurred, the central heating demand
indicator will flash slowly (approximately once per second).
The appliance can be reset by pressing the reset button and
holding in for 5 seconds. Check that the gas supply has not been
interrupted.
If this condition continues to occur, then call a service engineer.
AIR FLOW DEVICE
The appliance will enter a lockout condition in the event of an air
flow fault.
If the controls fail to detect the correct air flow through the
appliance the electricity supply to the gas valve will be interrupted.
If an air flow fault has occurred, the domestic water demand
indicator will flash (approximately five times per second).
The appliance will try to re-light after a waiting period of
approximately 4 minutes. Check that the flue terminal has not been
obstructed or damaged, and the condensate drain pipe is not blocked
outside with debris.
If this condition continues to occur, then call a service engineer.
REMOVAL AND REPLACEMENT
OF THE FRONT PANEL (See Fig. 4)
Removal:
Holding the panel at the edges, slide it upwards to disengage the
clips and ease the top edge forwards and upwards to raise it clear of
the two pegs on the top edge of the facia.
Replacement:
Locate the two holes in the bottom edge of the front panel over
the two pegs on the top edge of the facia and reverse the removal
procedure.

12
A diagnostic system is provided which gives a flashing light
display on the facia panel. Press the reset button to attempt to restart
the appliance. If the appliance does not return to normal operation
then contact your installer/engineer or Worcester Heat Systems
advising of the appliance serial number and the flashing light
sequence, i.e. which lights flash and at what speed.
More than 30% of all calls made to Worcester Heat Systems to
report appliance faults or breakdowns prove to be false alarms, as there
is often a simple explanation for the apparent malfunction.
So, to help you save time and money – not to mention frustration
and inconvenience – please refer to the General Information, Notes and
Lighting Instructions ensuring all controls are set correctly.
If, after following the instructions the appliance still fails to operate
correctly call the Worcester Heat Systems Service Centre on 08457
256206. Arrangements will be made for an engineer to call as soon as
possible.
If it is known or suspected that a fault exists on the appliance it
must not be used until the fault has been corrected by a competent
person.
CALL-OUT CHARGES
All of our field service engineers are factory trained.
If you request a visit from an engineer and your appliance has been
installed within the last 12 months, no charge will be made for parts
and/or labour, providing:
•The appliance was commissioned correctly on installation.
•An appliance fault is found and the appliance has been installed
within the past 12 months.
A call-out charge will be made where:
•The appliance has been installed for over 12 months, or
•Our Field Service Engineer finds no fault with the appliance (see
note), or
•The cause of breakdown is with other parts of your
plumbing/heating system, or with equipment not supplied by Worcester.
NOTE: Invoices for attendance and/or repair work carried out on
your appliance by any third party will not be accepted.
APPLIANCE FAILS TO
OPERATE

13
MAINTAINING YOUR
APPLIANCE
Your new Worcester 26CDi Xtra gas-fired appliance
represents a long-term investment in a reliable, high quality
product.
In order to realise its maximum working life, and to ensure
it continues to operate at peak efficiency and performance, it is
essential that your boiler receives regular, competent servicing
and annual maintenance checks beyond the initial 12 month
guarantee period.
Regular service contracts can be arranged with your installer
– however if you have difficulty making a satisfactory
arrangement simply contact Worcester Heat Systems Contracts
Department on 01905 75624 for help.

14
SERVICE CENTRES
CONTACT NUMBERS:
UK Call Centre Tel. [phone]
UK Call Centre Fax. [phone]
Scotland only Fax. [phone]
OPERATING HOURS:
Mon - Fri 8.00am to 6.00pm
Sat 8.30am to 1.00pm
Please contact our UK Call Centre number where our friendly operators
will book your call with one of our team of nationwide engineers.
NOTE:
Sunday and Bank Holiday cover is not available

15
YOUR WORCESTER
26CDi XTRA
GUARANTEE
This appliance is guaranteed against faulty materials or
workmanship for a period of twelve calendar months from the
date of installation subject to the following conditions and
exceptions.
1. That during the period of this
guarantee any components of the
unit which are proved to be faulty
or defective in manufacture will be
exchanged or repaired free of
material charges and free of labour
charges by Worcester Heat Systems
Limited.
2. That the householder may be asked
to prove the date of installation,
that the appliance was correctly
commissioned and, where
appropriate, the first 12 month
service has been carried out to the
satisfaction of Worcester Heat
Systems Limited when requested.
3. That any product or part thereof
returned for servicing under the
guarantee must be accompanied by
a claim stating the Model, Serial
Number, Date of Installation.
4. That Worcester Heat Systems
Limited will not accept
responsibility for damage caused by
faulty installation, neglect, misuse
or accidental damage, the non-
observance of the instructions
contained in the installation and
Operating Instructions Leaflets.
5. That the appliance has been used
only for normal domestic purposes
for which it was designed.
6. That this guarantee applies only to
equipment purchased and used in
mainland Great Britain.
This guarantee is given in addition to all your normal statutory rights.

EXCELLENCE COMES AS STANDARD
Worcester Heat Systems Limited. Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: [phone]. Fax: [phone].
Technical Service Helpline 08705 266241.
www.worcester-bosch.co.uk
8 716 145 160d 12/00
GUARANTEE
REGISTRATION
You should complete and return the postpaid Guarantee
Registration Card within 14 days of purchase.
The card will register you as the owner of your new
Worcester 26CDi Xtra appliance and, while this will not affect
your statutory rights in any way, it will assist us to maintain an
effective and efficient customer service by establishing a
reference and permanent record for your boiler.
IMPORTANT: SERIAL NUMBER. Copy the number off the
Guarantee Card.
FOR YOUR OWN RECORD
MODEL SERIAL NUMBER
(See identity label inside appliance casing)
TYPE/SIZE DATE OF INSTALLATION
CORGI CONTACT
All CORGI Registered installers carry a CORGI ID card and
have a registration number. Both should be recorded in your
central heating log book. You can check your installer is
CORGI Registered by calling CORGI on 01256 372300
Do not forget to keep the Log book
in a safe place.