Handover; Inspection And Servicing - Worcester 25Si Installation And Servicing Instructions

If the appliance is to be passed over to the user immediately
then set the controls to the users requirements.
If the appliance is to be left inoperative in frosty conditions then
set the programmer, if fitted, to off. Do not turn the electricity or
gas supplies off. The appliance will operate under the control of
the integral frost protection facility.
If there is any possibility of the appliance being left totally
unused in freezing conditions then switch off the gas and
electricity and drain the appliance and the system.

13. Handover

Fig. 39. Facia controls
Central Heating
Reset
Power ON
Indicator
Button
Indicator
Light
!
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Mains Central Heating
ON/OFF
Operation and
Switch Temperature
Control Knob
13.1 Hand over the User Booklet.
13.2 Explain how to operate the appliance safely and efficiently.
13.3 Tell the user what to do if the appliance is not to be used in
very cold conditions.
13.4 Tell the user what to do if the system pressure falls.
13.5 Explain that regular servicing will maintain the safe and
efficient operation and extend the life of the appliance. WHS can
offer a comprehensive maintenance contract.
13.6 Tell the user that any work on the appliance must only be
carried out by a competent, CORGI registered, person.
13.7 Complete and hand over to the user the Benchmark
Log-Book.
14. Inspection And Service
14.1 The extent of the service is determined by the operating
condition of the appliance when tested by a competent person.
It is the law that any service work is carried out by a competent
CORGI registered person.
14.2 Inspection
Check that the terminal and the terminal guard, if fitted, are clear
and undamaged.
If the appliance is in a compartment or cupboard check that the
specified service space around the appliance is clear. Refer to Table 8.
Check all the joints and connections in the system and remake
any that show signs of leakage. Refill and re-pressurise as
described in Section 12-Commissioning.
Operate the appliance and take note of any irregularities. Refer to
Section 18-Fault Finding for rectification procedures.
Check the combustion performance
Remove the cap from the sample point on the top of the
appliance. Refer to Fig 34.
Connect the sampling meter.
With the appliance at maximum rate and stable in the DHW
mode expect readings of NG 5.5 - 8.5% CO2, 0.002 - 0.015% CO.
These figures cover all flue conditions.
Refit the cap after the test.
Disconnect the electrical supply at the mains and turn off the
gas supply at the gas service cock on the appliance before
Domestic Hot
Burner
Water Indicator
Operation Light
Light
Domestic System
Hot Water Pressure
Temperature Control
Knob
starting any service procedures.
Always test for gas soundness after the service has been
completed.
14.3 Component Access
To service the appliance it may be necessary to remove some or
all of the following parts to gain access to components which
may need to be checked or replaced.
Cabinet
Facia Panel Unscrew the two screws and lower. Refer to Fig 40.
Inner Case Cover Unscrew the four fixing screws and remove
the cover. Refer to Fig 40.
Fig.40. Inner case and facia fixing
Gauge
Facia
Combustion Chamber Unscrew the two screws at the top and
Fan
Flue Hood Remove the fan. Unscrew the four screws and
Burner
14.4 Component Cleaning
Only use a non-metallic brush to clean components.
Clean the fan taking care not to block air flow detector.
Clean the burner to ensure that the blades and injectors are clear.
Do not us a metal probe to clean the injectors.
Clean the electrodes, replace if there is any sign of deterioration.
Clean the heat exchanger. Cover the gas inlet tube and remove
any deposits from the heat exchanger from the top and bottom.
Carefully straighten any distorted fins on the heat exchanger.
Check the combustion chamber insulation and replace if there is
any sign of damage or deterioration. Refer to Section 15.4.5.
Clean the controls in situ using a non-metallic brush.
Carefully refit any components removed in the reverse order.
Check that all screws are tight and the connections properly
remade with the appropriate gaskets/O-rings.
Re-commission, as necessary, for correct operation to the users
requirements. Refer to Section 12 Commissioning.
20
Unscrew the screw at the top of the cabinet, release
the sides. Lift up and away from the top locating
pegs.
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the two wing nut extended screws at the sides, pull
forward and remove. Refer to Fig 41.
Carefully pull off the electrical connections and the
tubes from the airflow-sensing device. Unscrew the
four screws and remove the fan assembly. Refer to
Fig 42.
remove the hood. Refer to Fig 43.
Remove the combustion chamber. Carefully pull off
the connections to the spark and flame sensing
electrodes. Release the union nut beneath the
burner and remove. Refer to Fig 44.
Fixing screws
(4)
Inner
case
cover
Facia panel
fixing screws
(2)