I have fedders home heater(seems very old) it is like a rectangluar box and with little manual access. I can see the flame and I hear the sound of air blowing but still there is no potential hea t I witness :confused: and I tried turning it on and off (the thermostrat) but still no change in the situation :mad: please help..!

When last time u changed the filter,, has to have air coming in before it can blow out