Design Information | 3
M2250322_en | Installation instructions Wood chip boiler T4e 200-350
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3.5.2 Simultaneous operation with other air-drawing systems
Where the boiler is operated in room air-dependent mode with simultaneous operation of
other air-drawing systems (such as room ventilation), safety devices are necessary:
▪ Air pressure monitor
▪ Flue gas thermostat
▪ Window-tilting drive system, window-tilting switch
NOTICE! Clarify the safety devices with appropriate flue sweep / chimney sweep
Recommendation for room ventilation:
Use “intrinsically-safe” room ventilation systems with F classification
As a basic rule:
▪ Room under-pressure max. 8 Pa
▪ Air-drawing systems must not exceed the room under-pressure value
– If the room under-pressure value is exceeded, safety equipment (under-pressure
monitoring system) is necessary
In Germany, the following additional requirement must be observed:
A gauge that monitors the negative pressure gauge (e.g. air pressure sensor P4) and is
approved by the DIBt (German Technical Authority in the Construction Sector) must be
used. This monitor tracks the maximum negative pressure of 4 Pa at the installation site.
In addition, at least one of the following three requirements must be met:
(Source: Section 4 MFeuV 2007 / 2010)
▪ Dimension the cross-section of the combustion air opening so that when the boiler is
in operation the maximum under-pressure is not exceeded (simultaneous operation)
▪ Use safety equipment that prevents simultaneous operation (alternate operation)
▪ Monitor the flue gas outlet using safety devices (such as a flue gas thermostat)
Simultaneous operation
An approved safety system (such as an air pressure monitor) ensures that during
simultaneous operation of the boiler and the air-drawing appliance the pressure
conditions are maintained. In the event of a fault, the safety system will switch off one of
the air-drawing systems.
Alternating operation
An approved safety system (such as a flue gas thermostat) ensures (e.g. by switching off
the power supply) that the boiler cannot be operated simultaneously with the air-drawing
appliance.
