The LGA...  are used for the startup and supervision of atmospheric gas burners of small to medium capacity (without fan) in intermittent operation. The flame is supervised with an ionization probe.  Using the appropriate adapters, the LGA...  can replace their predecessor types LFI7...  and LFI5...  in terms of function and size.  LGA41.173A27 and LGA52.171B27 are suited for use with direct-fired air heaters.