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Hello Preston, you many not refit the blower door properly so that the door switch has not closed... that is most likely the problem.
We can go from here without any time limits, however if that solves the problem, please rate my work, its how I earn a living and does not increase your charges.
Thanks, two red led flashes point to a stuck pressure switch, or a bad printed circuit card.
Locate the pressure switch on the wiring diagram then follow the wires to it on the furnace itself, its round item about the size of a hock puck, with two wires and two small rubber tubes attached. Remove one of the wires, then attempt to restart the furnace, it should fail to ignite....and produce a different error code. If it does that we can be pretty sure its switch is stuck closed and will do a few clean out procedures, if that fails we will replace the pressure switch.
If the error code does not change, then a bad printed circuit board is likely the problem.
Let me know what you can discover, we can go from there.
Hello again, if you remove the front covers on the furnace and send me a picture that shows whats inside, taken from about 8 feet away I can point the pressure switch out to you.
Use the paper clip icon at the right end of the tool bar for that.
We can go from there.
If you do buy a new pressure switch, we will need to confirm with the vendor that it is for your exact model (full model number not just the '8.v'... the 8 to 12 digit model number.
A flash picture would be best, ***** ***** clear well focused close up of the wiring diagram glued inside the blower door will help, it needs to be well lit, and taken from straight on.
Do the 'remove wire' test I mentioned earlier and tell me if the error code changes. The item I circled earlier at the top of the furnace is almost certainly the pressure switch... it is a dual pressure switch, to accommodate the two stage gas valve installed.
Do not leave the furnace un-attended with the pressure switch wire on LP1 removed.. its a brief test only. The pressure switch is a key safety item on the furnace.