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What is the model on the unit and is the error on the unit itself?
The E2 is an open pressure switch error. Does the inducer vent motor come on. (Turn power off to furnace, then back on and call for heat, see if inducer fan starts)
The OP is normal operation
The LO indicates unit is operating at low stage heat
If we get the E2 that is indicating inducer motor is not drawing sufficient vacuum on pressure switch.
Let me know and we will go from here as needed.
I would make sure there are no obstructions in either intake or exhaust vents.I have see as small as a spider web effect vacuum .Next make sure hoses from inducer to switch are not kinked or cracked
Remove hoses and clean and clean fittings where they connect to switch and inducer with a straightened paper clip. Then make sure main drain is flowing freely with no water backing up in hoses.Make sure all wiring is making good connections at switch and control board.
Beyond that you will need to call in a tech with a manometer to test and determine if the switch is bad or if the inducer is the issue not pulling sufficient vacuum on the switch.
Sorry for delay.Been trying to find some pics. The hoses from inducer to pressure switch should have air only. Drain hoses should have no standing water except in trap and main drain going outside should have no standing water.
Not finding very good pics. This one shows the hose which should have no signs of water. And shows how to check vacuum with a manometer. You could remove the hose from swich and after inducer starts suck on hose and see if furnace will stay running.That would indicate an issue with inducer not pulling enough vacuum.
One is for low stage and the other is for high stage
That is correct