Specific Maintenance Operations; Detection/Ignition Electrode Replacement; Dismantling The Water-Water Exchanger; Flow And Return Sensors - Baxi 800 Combi 2 Series Installation And Service Manual

10.4

Specific maintenance operations

Fig.73 Remove detection/spark ignition
electrode
Fig.74 Remove flow and return sensors
68 800 Combi 2
10.4.1

Detection/ignition electrode replacement

Replace the detection//ignition electrode in the following cases:
1. Ionisation current <4 μA. To do this, activate the "chimney sweep
function" (chapter "Combustion settings") and set the boiler to the
minimum power. The ionisation value is visible with setting GM008
(chapter "Reading out measured values").
2. Electrode worn.
3. Distances out of range (chapter "Electrode distance").
To remove the electrode:
Disconnect the power supply to the boiler.
Cut off the gas supply to the boiler.
Remove the front panel on the boiler (case) and remove the electrode
pin and the earthing cable.
Unscrew the 2 screws on the ignition electrode and remove it.
Fit the new electrode with the gasket. To re-assemble, perform the
above actions in reverse order.
10.4.2

Dismantling the water-water exchanger

The stainless steel plate water-water heat exchanger can be easily
removed, as described below:
1. Disconnect the power supply to the boiler;
2. Close the gas cock;
3. Close the heating system return and flow cocks.
4. Drain the system, if possible only the boiler, using the specific drain
cock (E);
5. Empty the water contained in the domestic water circuit by opening a
user cock;
6. Remove the silencer, then loosen the two Allen screws Ø 6 mm (A)
securing the heat exchanger and remove it from its seat;
7. Use a natural product (e.g. vinegar) to clean the water-water heat
exchanger;
8. To re-assemble, perform the above actions in reverse order.
10.4.3

Flow and return sensors

There is one sensor on the flow (red wires) and one sensor on the return
(blue wires).
1. After noting the position of each sensor, prise the sensor clip off the
pipe and disconnect the plug.
2. Connect the plug to the new sensor and ease the clip onto the pipe
in its original position.
10 Maintenance