I pressed and held the power button whild holding the other two buttons as described in the manual (troubleshooting sequence). It went through the test sequence with all lights on the panel lit, and it alternated some code three times(which I believe is correct)--it was UA02 then 8:98, or something like that. Then it displayed nE after that sequence. I stepped through with the pause button as described, and got temps that were accuate (~20 C on both readings). The motor and igniter did what they were supposed to.
There was about 100 VDC on valve #1 until about 10 seconds after the flame lit, then it went to 0 VDC after the igniter went off. Valve #2 had 0 VDC until the ignition sequence began, went to 90 VDC and then went to 0 VDC when the voltage to valve #1 went to 0 VDC.
I tried the semiconductor test, and one reading said 300 ohm, and the other said 600 ohm. They were both supposed to be 300 ohm.
The flame detector said less than one ohm before ignition, and upon flame light, it went open, as it was supposed to.
I have a "cooling" light on the panel that is always lit, and never goes out. All of the other functions seem to operate normally.
I would feel much better about replacing a $100 board, if that were the problem. Where do I find that?
Thanks for your help.