Rising flame rectification reading
Wondering if anyone has experienced this. I was working on a Commercial RTU (Lennox)
Heating was locking out on Flame failure.
I checked board was correctly grounded-ok, clean flame rod, and flame rod wire had good continuity.
When I checked the uA I found at first 3.5 to 4uA and within a minute it would rise up to 9uA and then would shut off. Same thing would happen several times and then would lock out.
I ended up changing ignition control board and works well (4uA)
Explained to owner and they told me that in the past 3 years the ICB has been has been changed.
Have you experienced this before? Why would this happen? Never seen a runaway flame rectification.