Things to know about exhaust air controls
Safety devices are subject to the building regulations and are only permitted if they bear the mark of conformity (Ü mark) from the German Institute for Building Regulations (DIBt)!
Source: State Building Regulations § 20 Bauprodukte (1)
When buying, pay attention to the DIBt approval!
Your exhaust air control (window contact switch) should definitely have a DIBt approval so that you can be sure to get the highest possible safety. Your chimney sweep will also look for this test when recommending such a system.
Excerpt from the Firing Ordinance (§4 Para. 2 FeuVO)
§ 4 Installation of fireplaces
(2) Room air dependent fireplaces may only be installed in rooms, apartments or utilization units of comparable size, from which air is extracted with the help of fans, such as ventilation or warm air heating systems, extractor hoods, exhaust air laundry dryers, if
1. a simultaneous operation of the fireplaces and the air extracting systems is prevented by safety devices, or
2. the flue gas routing is monitored by special safety devices, or
3. the flue gases from the fireplaces are discharged via the air extraction systems, or
4. the design or dimensioning of the air extraction systems ensures that no dangerous negative pressure can occur.
5. builders or owners of the combustion system are generally obliged to comply with the regulations of the combustion ordinance.
Source: Quote from Ministerialrat van Hazebrouck, Oberste Baubehörde im Bayerischen Staatsministerium des Innern (Bavarian State Ministry of the Interior), 04.06.2009.
Exhaust air control means a device that reliably puts an exhaust air system out of operation as long as certain conditions do not exist that allow the exhaust air system to start.
The best known example of an exhaust air control is the fume hood control.
Basically, an exhaust air control is always required if there is both an exhaust air system (extractor bonnet, bathroom fan, exhaust air dryer, etc.) and a combustion facility (wood-burning stove, Swedish stove, gas boiler, etc.) in the same living space. As a rule, chimney sweeps point out that such a safety device is necessary.
Paragraph 4 of the FeuVO (Fireplaces Ordinance) states that if a so-called room-air-dependent combustion facility is present, fresh air must be supplied if an exhaust air system is put into operation at the same time.
In other words, fresh air for exhaust air; here it is exclusively a matter of pressure equalization. For reasons of energy saving, apartments / houses are being built ever tighter, doors and windows insulated, walls insulated and every crack, no matter how small, sealed. If an exhaust air system is now put into operation in such a living space, a considerable negative pressure is immediately created and thus the danger that the pressure will equalize via the combustion site, which is after all openly connected to the chimney. Thus, not only dirty smoke and possibly soot are sucked into the room, but above all the toxic and far too often deadly gas carbon monoxide, CO for short, and this must be avoided at all costs.
Exhaust air laundry dryers, but also other exhaust air systems with very high power consumption, occupy a special position. While fume hood controls regularly switch only up to 5 amps, exhaust air controls for the power-hungry appliances must be able to switch much higher powers. They are identical in design to the controls for the range hoods, but are equipped with a much thicker relay. The principle is also the same, if a window is opened, the clothes dryer can be put into operation. However, due to lack of high demand, we offer here only two variants. The radio exhaust air control FDS 216 (300460) in the adapter plug housing and the cable exhaust air control KDS 116 (300750) in the installation box with screw terminals for connection. From a purely technical point of view, there is no reason why these should not also be used for the extractor hoods, but the larger size of the 16A relay means that only one of these components can be accommodated in the housing, and therefore these two circuit-breakers do not have DIBt approval. The DIBt requires that all safety-relevant components are redundant, i.e. double.
Now there are also gas heaters that are installed in windowless sanitary rooms, for example, where a bathroom fan is supposed to draw humid air out of the room at the same time. Here it would be impossible to open a non-existent window to equalise the pressure. In these circumstances, only gas heaters that switch off or release the bathroom fan via ignition information should be installed. The information as to whether a gas boiler is currently ignited and in heating mode is ideally provided by a potential-free contact in the boiler that is accessible to the installers via a screw terminal. As these contacts are usually not able to withstand high loads, i.e. they cannot switch a fan motor directly, Elektrotechnik Schabus has two exhaust air controls that can query precisely these potential-free contacts and, depending on them, switch a potential-free changeover relay to which the bathroom fan is connected. We call these exhaust air controls "gas heater controls" to better distinguish them from the other exhaust air controls, although of course they do not control the gas heater, but only the fan motor is switched on and off, as with all others.
For a radio connection between the gas boiler and the bathroom fan, select the FGS 170 set (300714), consisting of a transmitter that interrogates the potential-free contact of the gas boiler and is operated with 230 volts mains voltage, and a receiver with relay contact that switches the bathroom fan and also requires no batteries. For an adjacent room - the radio link does not go any further - which may have another fan, there is an FGS 170-E additional receiver (300701), which is coded to the transmitter at the factory. For the cable connection between the potential-free contact of the gas heater and the switching relay for the bathroom fan, we build the cable gas heater control KGS 116 (300715), which in contrast to the radio control, which only switches 5 A, can even switch 16 A, and thus additional fan motors can work on only one relay.
