Gentlemen: Thank you so very much for your suggestions. I was going nuts trying to get this $%(*#! to work. I had almost exhausted all ideas until I read your comments. I tried them and it worked.
I had the tank split last February during the Deep Freeze that struck Texas and had it welded up. I put the mess back together (and insulated the tank this time. The original insulation had disappeared years ago) and put it back in. No fire. Replaced the ECO and two sensors to no avail. I had traced the workings down to the control board (the most expensive part, naturally) and was about to reach for the credit card when I stumbled upon this page. The heater is now running to ops check everything but I think that, with your help I've got it whipped. We shall see.
