Lennox Limit Switch / Watchguard Issue
Hi all - first off, I have to state up front that unless things are realtively simple and idiot-proof, I likely won't be doing much DIY work - what I hope to get from members here is some guidance that helps me know what I'm talking about so if I do need to call a pro in, I know enought not to get gouged! Any specific pointers on that would be much appreciated!
I have a Lennox G43UF unit about 5 yrs old and am getting the red blinking light and steady greeen - this code is apprently to do with the limit switch / watchguard system. What's happening is that usually the furnace goes on, ignites, etc. but doesnt stay on too long and never reaches the temperature specified by the thermostat. Once it turns off, it seems to stay off for quite some time before coming on again (to me, I'm guessing it's triggering the high limit switch and the watchguard kicks in for 1 hour?). If i do an on/off to the furnace power it seems to "restart" this cycle and kicks the furnace back on (but it still switches off before getting up to temperature).
With the past few days being warmer though, I've noticed at least once that the furnace has NOT stayed off for an hour. i.e. I heard it come on for a while, it eventually went off for a while, but then it restarted itself not too long after this (i.e. it wasn't "forced" off for 1 hour).
(and FYI, one source I've checked was the HVACmechanic.com forum where a poster named marchvac sounded very familiar with this specific issue but I can't seem to find him anywhere - and leads would be appreciated - may be from a Yuri if you're out there as well?)