Bosch Condens 7000 WP - Replacement of the Gas;Air Check Valve; Replacing the Coding Plug; Replacing the Air;Gas Ratio Control Valve

Inspection and maintenance
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Condens 7000 WP – 6721842519 (2022/03)
▶ Carry out a check by measuring the ionisation current ( § 10.13,
p. 36).
10.16.3 Replacement of the gas/air check valve
Observe the replacement period for the flue gas check valve.
▶ Replace the gas/air check valve, depending on the service life (
Tab. 19, p. 36).
▶ Switch off the appliance.
▶ Undo the 4 screws [1] of the gas-air mixing hose.
▶ Replace the gas/air check valve [2].
Fig. 45 Replacement of the flue gas check valve
▶ Clean the contact surfaces of the gas-air mixing hose and the fan.
▶ Install the new flue gas check valve.
▶ Uniformly tighten the screws hand-tight.
▶ Start up the boiler.
▶ Check the gas tightness of the removed parts.
▶ Test the function of the valve by measuring the air resistance on the
heat exchanger.( § 10.9, p. 35).
10.16.4 Replacing the coding plug
NOTICE
Damage due to electrostatic charge
Printed circuit boards in electronic components are susceptible to
electrostatic charge (ESD).
▶ Wear an earthed wrist strap when working on electronic components
( § 7.1, p. 18).
▶ Switch off the appliance.
▶ Open the top appliance cover ( § 7.2, p. 18).
▶ Detach the bracket of the burner control unit [1].
▶ Push the burner control unit to the left [2].
▶ Lift the front of the burner control unit so the coding plug is easily
accessible [3].
▶ Remove the coding plug [4].
▶ Attach new coding plug.
Fig. 46 Replacing the coding plug
▶ Mount the burner control unit again by following the above steps in
reverse order.
▶ Screw down the bracket of the burner control unit.
▶ Close and secure the top panel.
▶ Operate the appliance.
10.16.5 Replacing the air/gas ratio control valve
Take the replacement interval of the air/gas ratio control valve into
account.
▶ If the air/gas ratio control valve is defective or depending on the
service life, replace it ( table 19, page 36).
▶ Switch off the appliance.
▶ Close gas isolator.
▶ Follow the replacement instructions provided when replacing the air/
gas ratio control valve.
▶Open the gas cock.
▶ Operate the appliance.
▶ Check the tightness of all gas-carrying components.
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