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Standard Equipment/Management System
Standard Equipment
Combustion Management System
The combustion management system utilizes the physical
correlation between the level of the ionization current
and the air factor λ. For all gas qualities, the maximum
ionization current results with air factor λ.
The ionization signal is evaluated by the combustion
management system, and the air factor is adjusted to
between λ=1.24 and 1.44. This range provides for an
optimum combustion quality. Thereafter, the electronic
gas valve regulates the required gas volume based on the
prevailing gas quality.
To check the combustion quality, the CO
O
content of the flue gas is measured. The actual values
2
enable the prevailing air factor to be determined. The
relationship between the CO
λ is illustrated in the table below.
Air factor λ - CO
/O
2
2
O
Air factor λ
1.20
1.24
1.27
1.30
1.34
1.37
1.40
1.44
1.48
The Vitocrossal 300 CU3A boilers come equipped with Lambda Pro, the industry's first intelligent combustion
management system. The boiler adjusts automatically to any gas type and quality without the need for a fuel
conversion kit.
18
content or the
2
or O
content and air factor
2
2
content
content (%)
CO
content (%) for natural gas
2
2
3.8
4.4
4.9
5.3
5.7
6.1
6.5
6.9
7.3
Vitocrossal 300 CU3A 26 to 199 Technical Data
The Vitocrossal 300 CU3A gas-fired condensing combi-
boiler with Inox-Crossal heat exchanger, modulating
MatriX burner for liquid propane gas and natural gas
(available on all models), comes standard with:
■ boiler control unit with outdoor
temperature sensor, power/pump module:
- installation fittings with 30 psig pressure relief valve
- Temperature and pressure gauge field installation
on supply pipe.
- The boiler comes prewired and fully piped
internally for field connections.
- Side wall vent installations must include
Viessmann protective screen!
- Enclosure finish: black steel, powder-coated
Viessmann silver
- The Vitocrossal 300 CU3A comes ready for use
with natural gas and can be fuel converted to liquid
propane gas in the field.
To achieve an optimum combustion control, the system
regularly performs an automatic self-calibration; also after
a power failure (shutdown). For this, the combustion is
briefly regulated to max. ionization current (equals air factor
λ=1). The automatic calibration is performed shortly after
the burner starts and lasts approximately 5 seconds.
During the calibration, higher than normal CO
may occur briefly.
CO
9.6
9.2
9.0
8.7
8.5
8.3
8.1
7.8
7.6
2
content (%) for liquid propane gas
2
11.3
10.9
10.6
10.3
10.0
9.8
9.6
9.3
9.0
emissions
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