Burner/Combustion Chamber Door Assembly; Air/Gas Unit - Baxi COMBI 224 Installation And Service Manual

Fig.52 Removing the burner
Fig.53 Removing the air/gas unit
Fig.54 Adjusting the gas valve
C
1
A
2
D
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10.3.6 Burner/combustion chamber door assembly

1. Remove the detection/spark electrode.
See
Section 10.3.1
2. Hinge the control box down.
3. Hinge down the air/gas cover and disconnect all wiring plugs from
the PCB, noting their positions. Close the air/gas cover.
4. Using a 10mm spanner/socket, undo the 4 nuts holding the combus­
tion chamber door cover to the heat exchanger.
5. Undo the gas valve nut (30mm A/F).
6. Draw the combustion chamber/burner door assembly with the
air/gas unit away.
7. Remove the two Torx T30 screws holding the combustion chamber/
burner door assembly to the air/gas unit and disengage the tab on
the cover from the air/gas unit.
8. Fit new combustion chamber/burner door assembly to the air/gas
unit and reassemble in reverse order.
PN-0000247

10.3.7 Air/gas unit

1. Disconnect the electrode lead and earthing cable.
2. Hinge the control box down.
3. Hinge down the air/gas cover and disconnect all wiring plugs from
the PCB, noting their positions. Close the air/gas cover.
4. Disconnect the silencer from behind the air/gas unit.
5. Undo the gas valve nut.
6. Remove the two Torx T30 screws securing the air/gas unit to the
burner combustion chamber door assembly.
7. Push the flexible gas pipe downwards and ease the air/gas unit
away from the burner combustion chamber door assembly.
8. Fit the new air/gas unit to the burner combustion chamber door as­
sembly and reassemble in reverse order.
Note
Ensure the silencer is correctly positioned.
Setting the gas valve
Note
The CO
PN-0000246
suitable calibrated combustion analyser is available, operated by a
responsible person.
A Minimum rate (offset) adjustment screw.
B Maximum rate adjustment screw.
C Burner gas pressure outlet.
D Gas supply pressure outlet.
1
Note
B
The case front panel must be fitted when checking combustion.
Run the boiler for several minutes before checking the CO and CO
2
do this it is necessary to operate the boiler in Chimney sweep mode. En­
sure the boiler is at Maximum rate.
Insert the test probe in the flue sample point and allow the reading to
stabilise.
See
PN-0000234
Section 7.4.2 Gas Setting (Checking combustion — chimney
sweep mode). If the appliance cannot be operated on central
heating for more than 10 minutes without reaching maximum tem­
perature refer to section 14.1.
must only be checked and adjusted to set the valve if a
2
10 Maintenance
. To
2
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