Vacuum safety cut-off switch USA-4

Why does a chimney "draw the wrong way round"? A kitchen extractor hood or a toilet fan can draw exhaust gases out of the chimney into the living space. This must not happen and must be prevented. People must not be put at risk.

The Ordinance on Combustion Installations (FeuV § 4, Installation of Combustion Appliances) stipulates that when a room-air-dependent combustion appliance (e.g. fireplace, wood-burning stove, gas boiler) and an exhaust air fan (e.g. extractor hood) are operated simultaneously in a dwelling/house, it must be ensured that no carbon monoxide is drawn out of the combustion appliance.

The negative pressure safety cut-off switch continuously measures the differential pressure between the room and the chimney. If the chimney draws "the wrong way round," the extractor hood or ventilation system is switched off for safety reasons. The USA (negative pressure safety cut-off switch) is only "armed" once the fire is burning. Otherwise, the system remains on "standby."

An electronic component, flush-mounted, is installed in the immediate vicinity of the stove.

A precise negative pressure sensor monitors the differential pressure between the chimney and the room. If the negative pressure rises above 4 Pascal, for example due to the use of a bathroom fan, the fan system is switched off for your safety.

Draught fluctuations caused by gusts of wind are not taken into account and are filtered out by the electronics.

The USA naturally holds official approval from the German Institute for Building Technology (Deutsches Institut für Bautechnik).

The connection must be carried out by a qualified electrician, in accordance with the enclosed instructions.

Scope of delivery:

• USA control unit with attractive glass display
  
• Flue gas sensor connection
  
• Negative pressure hose (5 m)
  
• Connecting cable (5 m)
  
• Flush-mounted box
  
• Escutcheon
  

Manufacturer: BRUNNER