Inspection and maintenance
35
Condens 7000 WP – 6721842519 (2022/03)
▶ Check if the pressure compensation hose [2] is connected correctly
with the gas valve and air collector.
Fig. 42 Check the connections of the pressure compensation hose
▶ Install the gas hose.
Fig. 43 Installing the gas hose
10.9 Measure the heat exchanger air resistance [R
x
]
By measuring the air resistance [R
x
], it can be determined if the heat
exchanger has been sufficiently cleaned. For this purpose, the
measurement is compared with the measurement of the initial
commissioning. [R
0
] ( § 10.18, p. 38).
10.9.1 Preparation
To ensure a correct measurement, remove the soiling that has been
released during cleaning as well as the remaining rinsing water by
temporarily putting the boiler into operation.
▶ Make sure that the boiler can release its heat to the system.
▶ Open the menu Function check > Burner.
▶ Start the Function check by setting the value to at least 50 %.
▶ Run the appliance 2 to 3 minutes.
▶ Deactivate Function check.
▶ Switch off the appliance.
10.9.2 Measure the air resistance [R
x
]
▶ Remove the cover of the condensation catch pan ( § 38, p. 34).
▶ Open the gas/air ratio test port by turning the adjusting screw
through 2 revolutions ( § 8.3, p. 22).
▶ Set the pressure gauge to“0”.
▶ Connect the pressure gauge to the gas/air ratio test port.
▶ Operate the appliance.
▶ Open the menu Function check > Fan.
▶ Start the Function check.
Now the fan is switched on. The burner remains switched off during
this function check.
▶ The air resistance is read-off in Pascal [Pa].
Attention! During the measurement, the air resistance is displayed
as negative value.
▶Stop the Function check.
▶ Close the gas/air ratio test port.
▶ Reattach the cover of the condensation catch pan.
10.9.3 Assess the air resistance [R
]
For the assessment of the air resistance above the heat exchanger, the
following applies: R
0
- R
x
= R
The maximum decrease in the air resistance [R
] differs depending on
the product type, and must not be exceeded.
Table 16 Maximum decrease of the air resistance depending on the
product type
Example 1: with an GC7000WP 145, an air resistance was measured
during commissioning [R
0
]= -2083. The resistance measurement is
carried out during the third maintenance visit [R
3
]. According to the
calculation, the difference was less than 500 Pa.
Table 17 Example 1: assessment of the air resistance at R
3
▶ Make a note of the value in the maintenance protocol ( § 10.18, p.
38).
Example 2: with an GC7000WP 145, an air resistance was measured
during commissioning [R
0
]= -2083. The resistance measurement is
carried out during the fifth maintenance visit [R
5
]. According to the
calculation, the difference was more than 500 Pa.
Table 18 Example 2: assessment of the air resistance at R
5
This could be caused by:
• Flue gas check valve clogged.
• The pollution degree in the heat exchanger is too high.
▶ Check the flue gas check valve for defects ( § 10.16.3, p. 37)
▶ Clean the heat exchanger again ( § 10.5, p. 33).
▶ If the air resistance is still high: contact the Boschcustomer services.
0010041396-001
2
2
1.
Product type Max. R
GC7000WP 125 400 Pa
GC7000WP 145 500 Pa
R
0
R
3
R
Action
-2083 -1857 226 No action required
R
0
R
5
R
Action
-2083 -1519 564 Find out and eliminate
the cause for the high
value.
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