Bosch Condens 8300i W - Adjusting the Operating Pressure of the Heating System; Replacing the Gas Valve

Inspection and maintenance
47
Condens 8300i W – 6721841531 (2022/10)
▶ Replace the condensate trap and check for tightness.
Fig. 63 Install the condensate trap
9.18 Adjusting the operating pressure of the heating
system
Table 27
If the indicator is below 1 bar when the system is cold:
▶ Fill the hose with water to prevent air entering the heating system.
▶ Top up the water until the indicator is between 1 bar and 2 bar again.
If pressure is not being maintained:
▶ Check the expansion vessel and heating system for leaks.
9.19 Replacing the gas valve
▶ Close the gas isolator.
1. Unscrew the bayonet connection.
2. Unscrew the union nut.
3. Remove the gas pipe.
Fig. 64 Removing the gas pipe
1. Unplug the plug.
2. Unscrew the union nut.
Fig. 65 Unplugging the plug and unscrewing the union nut
1. Remove the 2 screws.
2. Remove the air/gas ratio control valve.
Fig. 66 Removing the gas control valve
▶ Install the air/gas ratio control valve in reverse order, and check the
gas/air ratio.
Display on the pressure gauge
1 bar Minimum filling pressure when system is cold
1 - 2 bar Optimal filling pressure
3 bar The maximum operating pressure for the maximum
heating water temperature must not be exceeded,
otherwise the pressure-relief valve will open.
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