2. Check the non-return valve for contamination and cracks.
1.
Fig. 49 Non-return valve in the mixing device
▶ Install the non-return valve.
▶ Install the mixing device.
▶ Tighten the screw and nut ([1] and [2], Fig. 48) on the mixing device
with 5.5+0.5 Nm.
9.11
Checking the electrical wiring
▶ Check the electrical wiring for mechanical damage.
▶ Replace defective cables.
9.12
Checking the expansion vessel
The expansion vessel must be checked every year.
▶ Depressurise the appliance.
▶ Adjust the pre-charge pressure of the expansion vessel to the static
head of the heating system, if necessary.
9.13
Checking heating block
▶ Remove cap from test port.
▶ Connect the pressure gauge.
Fig. 50 Test nipple at the mixing device
▶ Check actuating pressure with DHW maximum rated heat output at
mixing device.
The heating block must be cleaned if the following measurements are
obtained:
• GC8300iW 25 P < 6.2 mbar
• GC8300iW 35 P < 3.5 mbar
▶ Clean heating block if necessary ( Chapter 9.14).
▶ Remove the pressure gauge.
▶ Attach cap to test port.
▶ Check the gas/air ratio.
Condens 8300i W – 6721841533 (2022/12)
2.
0010018136-002
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9.14
Cleaning the heat exchanger assembly
Clean the heat exchanger with the cleaning brush set, which is available
as a spare part. Using chemical additives for cleaning on the heating gas
side is not permitted.
▶ Remove the condensate trap ( chapter 9.15, page 42) and place a
suitable container underneath.
▶ Remove the cover at the heating block.
▶ Clean the heating block with the cleaning knife from top to bottom.
Fig. 51 Cleaning knife
▶ Clean the heating block with the brush from top to bottom.
Fig. 52 Cleaning the heating block with a brush
▶ Remove the burner ( chapter 9.9, page 40).
Inspection and maintenance
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