-Small size indirect fired heaters -Low speed axial fan ( 900 rpm ) to reduce noise levels -High efficiency heat exchanger with a 4 tube circuit -Sealed combustion with automatic ignition -Multiple torch burners in sealed section -Fumes extraction fan allows direct evacuation to the building facia ( concentric wall exhaust ) or connection via a flue ( concentric roof exhaust or simple chimney ) -Power supply in 230 V single phase -Double deflection air supply grill -Low weight to reduce the constraints of support frames -Automatic fan thermostat -Overheating thermostats ( automatic + manual ) -Controlled via a pilot wire : only 1 thermostat ( optional ) is necessary to operate up to 6 heaters -Ionisation permanent flame control -Gas pressure supply: 20 or 25 mbar ( natural gas ) or 37 mbar ( propane gas ) Suspended warm air heaters with gas burner and axial fan