Earlier tonight, I told my husband that there was a tinking sound in the furnace fan. I didn't feel comfortable taking anything apart to look inside the fan, so I waited for him to get home. I told him about it, he went downstairs and a few minutes later when I got down there with him, he had disconnected the draft inducer by mistake! He put it back together and now all of a sudden we're getting the 3 flashing light that means pressure switch open with inducer on. We tried blowing and sucking into the hose. Worked for a few seconds, but then burners went out (safety feature) and error code came right back. As of right now, my husband sucked on the hose continuously, fired up the furnace and left that end of the hose off. We have heat again, but obviously we no longer have our important safety feature of the pressure switch function detecting the negative pressure. So my question is, how do we fix the pressure switch, when it only started acting up after my husband disconnected the draft inducer? I think it has to do with losing suction when he broke the seal, but I'm not an expert like you and am only guessing here. I appreciate your time and any help you can provide us with. Thank you very much. (Oh and the original problem with "tinking" sound was a piece of masking tape that somehow got in the fan.)

Some furneces have a wiring diagram pasted to a panel of the unit. If yours has one then I would look there first. If he disconnected any wiring then he may have replaced it backwards. Some units require strict pos/neg connections. If he puts them backwards that part will no longer function. Also look at your fuses if you see any.

Examine the hoses carefully for any splits, cracks, or holes. Also in taking the inducer apart, he may have jarred some rust loose which is now plugging the small hole where the hose attaches. Usually a large paper clip poked up through the hose nipple will dislodge any thing blocking the port.