Replacement Of Parts - Worcester W 125 FL Installation & Servicing Instructions Manual

Take care not to damage the two 'O' ring seals.
Unscrew the large heat exchanger retaining screw,
located at the rear of the combustion chamber just
above the burner blades, and lift clear the heat
exchanger assembly.
In hard water areas it may be necessary to descale the
heat exchanger body. A proprietary brand of descaler
should be used. Fill the heat exchanger with this
solution and leave until the solution stops bubbling.
Drain and thoroughly wash out the exchanger with clean
water.
Warning: Acid/water solutions must be used with
extreme caution. Take care not to splash on to the skin
or into the eyes. Wash any affected areas with large
amounts of cold water and seek medical advice.
Re assemble in reverse order taking care to locate the
heat exchanger on the two support hooks formed in
the appliance back plate.
9.3Pilot Assembly
Remove the appliance casing as described above.
Remove the pilot air supply pipe as described above.
Undo the union connection on the pilot gas pipe at the
pilot body.
Undo the two screws securing the pilot body to the
burner front rail and withdraw outwards and upwards
away from the pilot gas pipe.
Note: take great care to retain the pilot injector located
between the end of the pilot gas pipe and the inside of
the pilot body.
Inspect, clean and adjust as required.
Re-assemble in reverse order taking care to locate the
pilot injector correctly.
9.4Main Burner
Remove the appliance casing and pilot assembly as
described in sections 9.1 and 9.3 above.
Slacken the pilot pipe union at the gas valve end and
swing the pilot pipe to the left.
Undo the brass union nut holding the burner assembly
to the gas valve body.
To remove the assembly from the combustion chamber
it must be turned upside down. Proceed as follows.
Raise the front edge of the burner up into the
combustion chamber turning over away from the front.
Once the burner is upside down it can be withdrawn
from under the combustion chamber, the union passing
through cut-away in the front of combustion chamber.
Inspect and clean as required. Check the union joint
ring and replace if required.
Replace in reverse order taking care that the locating
pin in the rear of the burner locates with the slot in the
rear frame.
9.5 Final Inspection
Turn on the gas supply at the main gas service cock
and check for gas soundness in accordance with the
current edition of BS 6891 while the appliance is
running.
Re-commission the appliance as described in section
8.
8
10

Replacement of Parts

The law requires that any service work must be carried
out by a competent person such as British Gas or other
Corgi registered personnel.
Before commencing any service operation turn off the gas
supply at the main gas service cock.
10.1 Pilot Burner / Injector
Remove the appliance casing as described in section
9.1 above.
Remove the pilot assembly pipe as described in section
9.3 above.
Remove the retaining clip, holding the ignition electrode
and thermocouple to the body, from the side of pilot
burner body to release the electrode and thermocouple.
Fit the new injector and/or pilot burner in reverse order.
10.2 Ignition Electrode / Thermocouple
Follow the instructions given above in section 10.1 and
replace the faulty components.
10.3 Main Burner
Remove the appliance casing and pilot assembly as
described in sections 9.1 and 9.3 above.
Remove the main burner as described in section 9.4.
Replace the burner in reverse order taking care that
the locating pin in the rear of the burner locates with
the slot in the rear frame and that the union joint ring is
correctly positioned.
10.4 Piezo Spark Generator
Remove the front casing as described in section 9.1
above.
Pull forward the lower front of the casing to clear the
tap spindles and lift up the casing to unhook it from the
appliance back plate.
Unscrew the locking ring from the front of the Piezo
unit and withdraw the unit backwards through the
mounting plate. Pull off the two push on terminals and
discard the old unit.
Fit the new unit in reverse order taking care to locate
the unit on the small retaining peg. Also ensure that
the earthing wire is sprung into the hole in the mounting
frame.
10.5 Heat Exchanger
Remove the heat exchanger as described in section
9.2 above.
Remove the overheat thermostat and pilot air inlet
collector and fit to the new heat exchanger.
Ensure that two new 'O' ring seals are fitted to the inlet
and outlet pipes. Re-assemble in reverse order taking
care to locate the heat exchanger on the two support
hooks formed in the appliance back plate.
10.6 Water Control Assembly
a) Remove the front casing as described in section 9.1
above.
b) Isolate the appliance from incoming cold water