13.1.3 Cleaning The Burner And Checking The Electrodes; 13.1.4 Cleaning The Heat Exchanger; 13.1.5 Cleaning Condensate Trap; 13.1.6 Checking The 3-Way Valve - geminox THRs 0.9-9 C Installation And Maintenance Instructions Manual

Inspection/Maintenance

13.1.3 Cleaning the burner and checking the electrodes

▶ Disconnect the cables from the burner, fan and gas valve:
– Ignition cable from ignition electrode [7].
– Cable from ionisation electrode [5].
– 2 cables from fan [11].
– Air/gas servosystem [2].
▶ Undo 4 screws [12].
▶ Undo the union nut [3].
▶ Removing the burner.
▶ Clean the air inlet and then the gas inlet of the burner using a
household vacuum cleaner.
▶ Check the ignition electrode ( Fig. 44) and ionisation electrode
( Fig. 45).
▶ Refit components in reverse order using a new burner gasket.
A
2.25
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Fig. 44 Ignition electrode
[A] Top view
[B] Side view
A
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Fig. 45 Monitoring electrode
[A] THRs 0.9-9/2-17
[B] THRs 5-25

13.1.4 Cleaning the heat exchanger

▶ Remove burner ( chapter 13.1.3).
▶ Remove the condensate siphon and place a suitable container below.
▶ Flush out the heating block with water from the top.
▶ Clean the condensate pan and condensate connection.
▶ Refit components in reverse order using a new burner gasket.

13.1.5 Cleaning condensate trap

▶ Clean the condensate trap and re-fill with water.
40
B
B

13.1.6 Checking the 3-way valve

1
Fig. 46
▶ Once a year, check the piston return [2] of the 3-way valve [1].
▶ Clean and lubricate the return spring.
▶ If required, replace the return spring.
An installation key for the piston return of the 3-way valve is available
(part number: V00.24191).
13.1.7 Checking the expansion vessel (also see page 28)
The expansion vessel must be checked annually.
▶ Depressurise the appliance.
▶ Adjust the pre-charge pressure of the expansion vessel to the static
head of the heating system, if necessary.

13.1.8 Checking electrical wiring

▶ Check wiring for mechanical damage and replace faulty cables/leads.

13.1.9 Draining the appliance

▶ Switch off the power supply.
▶ Close the gas tap.
▶ Shut off the heating flow and heating return valve.
▶ Open the drain valve [2] and drain off the heating water via a
connected hose.
▶ Open the air vent valve [1] to allow air to be supplied to the heat
exchanger.
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Fig. 47
[1] Air vent valve
[2] Drain tap
THRs 0.9-9/2-17/5-25/10-35/10-50 – 6 720 808 441 (2016/03)
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