Need help in diagnosing vacuum switch errors. Question on the port that the vacuum hose connects to from the vacuum switch to the feed tube. I have the older model Mt. vernon stove in my basement, and the port on the feed tube is clearly open, this is where the vacuum hose from the vacuum switch connects too. You can stick a small screwdriver through the hole with nothing stopping it. I have another newer Mt. Vernon AE stove upstairs, constantly giving me vacuum switch errors. I have tested by bypassing the vacuum switch and the stove functions normally. When checking the port to the feed tube, is that hole suppose to be fully open or is there some type of a one way air valve in that port. I cannot pass a paper clip through this hole, it is blocked. When I attempt to blow air through it, very little air passes through it. It is not like the older model being freely clear of any constriction. Can someone check their stove to see if this is normal or not. I have replaced the older rectangular vacuum switch with the newer round style and the stove does not even fire up, and immediately gets the vacuum switch error. Upon power up, the stove opens the firebox and cleans, then the exhaust fan kicks on, next should start dropping pellets, this is where it stops and shows the vacuum switch error with the newer style switch in place. Any ideas?