Dear Experts,

I have an ArcoAire RPJll furnace, vintage 1993 - natural gas. The furnace came with a 50A55-120 controller and a WR 760-470 flame sensor. Since installation the furnace has consumed 1 to 2 flame sensors a year and 3 controllers since installation. At present it has the 50A55-843 controller and the WR 760-410 flame sensor. It works about 50 % of the time on first attempt to light and maintain the main burner and 50 % on the second attempt. The problem is that occasionally the system goes into lock out after failed attempts by the flame sensor and the control flashes the code indicating so. The conditions have been reviewed by technicians numerous times including; gas pressure in and at manifold, polarity, grounding, and control module grounding. The most recent attempt was to replace the flame sensor wire - to no avail. I'm at the end - the technicians (several) have thrown up their hands and I'm exhausted with worry that I'll come home to a cold house or worse - frozen pipes. The experts have followed the technical sheets and it works for a day, maybe two, then the condition is back again. Any ideas would be greatly appreciated. George

OK, this is going to probably come across wrong but is probably the best thing you can do. I don't like ArcoAire, are they even around still? How much money have you paid in the last 5 years fixing that thing? It is 13 years old and probably will crack the heat exchanger in 4 more years, if you can get it to run. Maybe its time to get a Rheem/Ruud, American Standard/Trane or Maytag furnace. By the way, I'm not a big fan of Maytag, it is just a glorified Nordyne, but a free 10 year part and labor warranty backed by one of the nations oldest companies is worth something, especially at today's repair costs. Some times you need to know when to cut and run. Also I'm not sure about the service company you are using, the third time should be the charm.

You have a bad ground somewhere. Look over your grounding from the panel to the furnace. Also all grounding in the furnace area. Remove the screws in the furnace area and clean off the paint then reassemble. Been there done that.