I have led light flashing three times it mean pressure switch open with inducer on

I have 80 plus furnace pressure switch open with inducer on what does that mean and how can I fix it

I just had the same problem with 3 flashes on the led light of my Concord 80 plus furnace. Replaced the pressure switch, but it did not help. Then I disconnected the rubber tube from the pressure switch and blew air into it using my mouth. It was blocked, like a lemon seed stuck in a drinking straw. Disconnected the other (inducer) end of the rubber tube, and used a straightened paper clip to dislodge whatever was stuck in there. Reconnected the tube and blew air through. Now it was like blowing through an unobstructed drinking straw. Reconnected the rubber tube to the pressure switch, and the furnace worked fine after that.