I have a Lennox EL296UHV furnace (2-stage, variable speed). About a month back it started showing code E229 Ignition on high fire. Some times it proceeds to heating/blowing after a couple attempts, some times it "waits" for a while before trying again. When it runs, it starts in stage 2 (high) and within a few seconds, switches down to stage 1 (low). I had the furnace maintenance done by a professional a week ago. He said everything is in perfect condition, but the issue continued. Previously, the furnace always started in stage 1 and some times would kick into stage 2 toward the end of cycle. I remembered changing the fan setting from "Auto" to "Circulate"about a month ago (this coincided with when the code E229 started). Last night, I changed the fan back to Auto and the furnace now starts in stage 1 and ends in stage 1. No more E229 or kicking in high at start. My uneducated guess at this point is that the Circulate mode is some how causing a condition that makes the control board think the low pressure switch is open (may be when the fan is still running when the thermostat calls for heat?). Did anyone else experience this with their furnace (with the fan in "circulate" mode or similar mode)?

I have a Carrier 394GAW000075 Gas Heater I'm trying to troubleshoot. I replaced the 3-wire intermittent pilot assembly (LH680005, reused the ignitor portion) last season but, I've had issues with the gas pilot catching consistently. I call for heat, the ignitor is clicking with spark but the pilot either doesn't ignite or takes along time to catch. The frequency of catching is getting lower & lower. If I light manually, the pilot lights instantly and the heater moves thru it's cycle and main burners fire and heat to set temp. Looking for suggestions. Ignitor gap issue? Intensity of spark issue? Pilot gas volume too low?