Commissioning
23
Condens 7000 WP – 6721841195 (2022/01)
8.3
Setting options for air/gas ratio control valve
Different air/gas ratio control valves are used depending on the rating
of the boiler. The positions of the various test ports and adjusting
screws vary accordingly.
Overview of air/gas ratio control valve GC7000WP 50, GC7000WP
65
Fig. 30 Overview of test ports and adjusting screws ≤ 70 kW
[1]
Adjusting screw CO
2
/O
2
[2]
Gas pre-charge pressure test port
[3]
Gas/air ratio test port
[4]
Gas/air ratio adjusting screw
Overview of air/gas ratio control valve GC7000WP 85, GC7000WP
100
Fig. 31 Overview of test ports and adjusting screws ≥ 85 kW
[1]
Adjusting screw CO
2
/O
2
[2]
Gas pre-charge pressure test port
[3]
Gas/air ratio test port
[4]
Gas/air ratio adjusting screw
[5]
Without function
8.4
Measuring the gas standing pressure (static)
The gas standing pressure must be stable to guarantee correct
operation of the boiler. The measurement is carried out when the boiler
is switched off.
▶ Switch off the appliance.
▶ Remove the front panel.
▶ Open the gas standing pressure test port by turning the adjusting
screw through 2 revolutions (
▶ Set the pressure gauge to “0”.
▶ Connect the pressure gauge to the test port.
▶ Measure the static gas standing pressure.
▶ Make a note of the value in the commissioning report (
p. 50).
▶ Close the inlet pressure test port.
8.5
Measuring the gas working pressure (dynamic)
The gas working pressure must be stable to guarantee correct operation
of the boiler. The measurement is performed at full load.
As the measurement is taken at the air/gas ratio control valve and not the
gas valve, the permissible gas working pressure may be reduced due to
the pressure drop between the gas valve and air/gas ratio control valve.
Example:
GC7000WP 100 to natural gas H, G20.
• Permissible gas pre-pressure: min. 17 mbar – max. 25 mbar (
• Pressure drop between gas valve and air/gas ratio control valve is
2.7 mbar (
Tab. 10).
Permissible limit values on the air/gas ratio control valve:
Min. 17 mbar – 2.7 mbar =
14.3 mbar
.
Max. 25 mbar – 2.7 mbar =
22.3 mbar
.
Table 10 Pressure drop between gas valve and air/gas ratio control valve
▶ Calculate the permissible minimum and maximum gas pre-pressure.
▶ Switch off the appliance.
▶ Remove the front panel.
▶ Open the gas inlet pressure test port by turning the adjusting screw
through 2 revolutions (
▶ Set the pressure gauge to“0”.
▶ Connect the pressure gauge to the test port.
▶ Make sure the heating system can release its heat.
▶ Operate the appliance.
▶ Open the menu
Function check > Burner
.
▶ Start the
Function check
by setting the value to 100%.
▶ Check whether the measured value lies within the calculated limit
values.
If the measured value lies outside the calculated limit values, do not
commission the boiler. The cause must be established and the fault
rectified. If this is not possible, shut off the gas supply to the system and
contact the gas supplier.
▶ Make a note of the measured value [mBar] after 1 minute in the
commissioning report (
▶ Deactivate
Function check
.
▶ Close the working pressure test port.
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Max. pressure drop for each gas type
[mbar]
Type
G20
G25 / G25.3
GC7000WP 50
1.5
2.0
GC7000WP 65
2.5
2.8
GC7000WP 85
2.6
3.3
GC7000WP 100
2.7
3.7
