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6
CLEARANCES
Minimum clearances in millimetres.
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.
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 fitted to the system then they
must conform to the requirements of BS2767. The radiator located in
the room where the room thermostat is sited must be controlled by a
thermostatic radiator valve.
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 The Worcester Technical
Helpline. 08705 266241
HOT AND COLD FLOW
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 provided that the
system is of the sealed system type. Open vent central heating
systems should be turned off until the supply is restored.
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.
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TO LIGHT THE APPLIANCE
Check that the water valves to the central heating circuit are open.
On sealed systems 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 ‘’position.
For Long Periods
Turn the operating switch to the ‘’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.
7
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 Bosch
Technical Helpline.
AIR SUPPLY FOR OPEN FLUED (O.F.)
APPLIANCES
Your installer will have made arrangements for an adequate
supply of fresh air to the appliance. Fresh air is required for
combustion. Do not block up any air ways which may be let into a wall
or door. Do not hang clothes or other combustible materials over the
appliance or against the flue pipe.
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. In particular, the flue pipe should not pass
through an airing cupboard space unless protected by a guard (such as
wire mesh) concentrically spaced 13mm (1/2in), as described in BS 6798:1987.
VENTILATION OF BALANCED FLUED (BF)
AND ROOM SEALED FANNED FLUE (RSF)
APPLIANCES
These are room sealed appliances 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 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 to ensure continuing high efficiency and
long life of your appliance. Suitable servicing arrangements should be made
with a competent third party. In the event of any difficulty in making
suitable service arrangements, Worcester personnel will be happy to discuss
regular servicing and offer a comprehensive maintenance contract.
IMPORTANT: Do not touch or adjust any sealed compontent.
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.
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 (RSF ONLY)
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. If this condition continues to occur, then call a
service engineer.
FLUE SPILLAGE DEVICE (OF ONLY)
The appliance is fitted with a device which detects the spillage of
combustion products from the draught diverter. In the event of the
flue becoming wholly or partly blocked this device will cut the gas
supply to the burner. If the device has activated, the D.H.W. demand
indicator will flash (approximately 5 times per second).
The device automatically resets after a waiting period of
approximately 20 minutes. If the blockage remains the appliance will
re-light briefly before the device operates again. Should the problem
persist consult your service engineer.
REMOVAL AND REPLACEMENT
OF THE FRONT PANEL (See Fig. 3)
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.
WARNING: Do not touch any component within the appliance
when it is running as some may be very hot.
Fig. 3. CDi with front panel removed.
Circulating
pump
Clip
Locating peg
Expansion
vessel
Gas valve
TO LIGHT AND STOP THE
APPLIANCE
24,28CDi RSF 35CDi II 24CDi OF 24CDiBF
Left-hand side 10 10 10 10
Right-hand side 10 10 10 10
In Front 600 600 600 600
Above 180 180 300 100
Below 200 200 200 200
