I have two Honeywell F300e air cleaner on both my furnaces. The lights never come on even when the fan is blowing.. I hear a zap very rarely. If I bang on the side of the air duct to loosen particles I can here it zap. Here is my problem, when I take the cells out to clean, they are not very dirty. I have had the furnace people out twice to look at them when the do my furnace annual and they said they are working but they said the neon lights must be burned out. When I used to clean the cells on the air cleaner at my last house they would be full of dirt and the water would turn black. Now at this house the water is hardly dirty. I find it funny both neon lights on each unit are burned out. If I can get them to snap does that mean they are working even though the lights do not come on. I can not find a test button. In some info I have found online it said the green light must be on to signal power in the cells. The funny thing is I had the cells completely out to wash the other day and I forgot to turn the unit off and I heard some electrical noises like zapping. Could someone please explain to me how these units work so I can diagnose the unit before I call for service again. Thanks. Could the unit have power but not on the collector plates?