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i think it is a 90% furnace its pvc pipe
Then the wind is pushing against your vent going out of the house. there should be a 90 degree elbow on it where comes out of the house. If there isn't then the wind is pushing right into the pipe. I will post my 90% explanation so you better understand what is happening. A 90% furnace condenses the exhaust gas so it has to drain this water out of the venting system. Every now and then on a 90% furnace if the vent pipe has a dip and traps this water it allows it to be hit by cold air when the furnace isn't on and will freeze. When it is frozen in the pipe it will block the amount of exhaust you are getting and not allow the pressure switch to prove therefore not turning on the igniter and causing a fault in the system. The system will go into a lockout time of 1 hour normally and then try again or you have to reset the thermostat or power to get it to try again. Another thing that can happen in extreme cold climates is if the drain going to the outside of the house gets plugged up or again freezes because it is not insulated at the outside or has traps caused by dips in the line then it will back up the water into the combustion chamber and cause the same type of havoc. I have even run across some exhaust vent pipes that have a dead family of birds in it or a bees nest.
i put a 90% elbo on pipe today that blows air out it seems to have worked . before that i stood outside next to pipe and when the wind blew i could hear my furnace begin to sputter . it only happends when its very cold and windy out .when its above freezing the furnace works great do you think i solved problem with the 90% and i put a 10inch extension on both pipes . its been about 9hrs and i have no problem its been cold and windy all day .let me know if you think i may have solved the problem.