Inspecting The Burner Electrodes; Testing The Differential Pressure Switch - Bosch Condens 7000 F Installation And Maintenance Instructions For The Contractor

Inspection and maintenance
Wet cleaning the heat exchanger
NOTICE:
Risk of material damage due to improper cleaning!
Dirt and moisture can damage boiler components during cleaning.
▶ During wet cleaning, protect electrical and other vulnerable
components (fan, air/gas ratio control valve, etc.) against moisture
and contamination.
▶ When wet cleaning, use a cleaning agent appropriate to the degree of
soiling (encrustation or soot).
The cleaning agent must be approved for use with aluminium.
▶ Clean the heat exchanger with water or a cleaning agent approved for
aluminium (see instructions provided by the manufacturer of the
cleaning agent).
▶ Spray the edges of the heat exchanger in particular.
Fig. 55 Wet cleaning the heat exchanger
Working on the heat exchanger during wet and dry cleaning
▶ Use a hose to rinse off any residues from the tundish or condensation
catch pan.
▶ Remove dirt trap (with boiler size 150-300 kW).
▶ Clean the condensation catch pan with water.
▶ Clean the siphon with water.
▶ Check continuity of condensate hose between the connector and
siphon.
▶ Insert dirt trap (with boiler size 150-300 kW).
▶ Install the siphon and fill with approx. 3 litres of water.
DANGER:
Danger to life due to poisoning! Siphons not filled with water can
cause danger to life through escaping flue gas.
▶ Fit the siphon ( Chapter 5.5, page 16 ff.).
▶ Fill the siphon with approx. 3 litres of water.
▶ Each time you carry out maintenance or an inspection, make sure that
siphon is sufficiently filled with water.
▶ Screw on the cover of the condensation catch pan
(with boiler size 150-300 kW).
▶ Fit the cap on the cleaning pipe socket (with boiler size 75-100 kW).
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11.9

Inspecting the burner electrodes

NOTICE:
Malfunction of boiler!
If the woven filaments of the burner rod surface come into contact with
the electrodes, this can cause a fault shutdown.
▶ Make sure that no woven threads are sticking out in the area of the
electrodes.
▶ Carefully cut off any fibres that are sticking out using scissors.
Checking the electrode position
▶ Move the burner into its service position ( Chapter 11.8, page 38).
If the monitoring electrode tapers to a point or has reduced in length,
this is a sign of significant wear.
▶ Replace the electrode.
▶ Check the gaps between the electrodes and compare them with
those shown in Fig. 56.
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Fig. 56 Electrode position (dimension in mm)
[1] Ignition electrode
[2] Monitoring electrode
▶ Replace the electrode block together with a new gasket if actual
values deviate from the specified parameters.
▶ If deposits are found on the electrodes, replace the electrode block
together with a new gasket or sand down the electrodes.
We recommend replacing the electrode block as part of the annual
maintenance.
▶ For completing maintenance see Chapter 11.12, page 43.
If a part needs to be replaced:
▶ Observe information in Chapter 11.11, page 41 onwards.

11.10 Testing the differential pressure switch

The differential pressure switch must be checked to ensure it is working
correctly each time maintenance or an inspection is carried out
(Chapter 16, page 54).
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Condens 7000 F – 6720871560 (2019/11)
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