OK, I'll try. Probably original rectangular box in floor(honorbuilt) with grate, connected to White Rodgers programmable digital themostat. Pilot on. WE put known working thermostats( From wall heaters in house -not digital) Nothing fires up heat. Maybe once every week or two the digital one works. The wire to heater goes through woodwook underneath floor (crawl space) to unit.

A second heater in kids room has a wall heater. Thermostat sometimes works but frequently needs to be jumpstarted at heater