[JRTJH]

Steve's advice is sound on the cleaning and repair of your furnace. Spider webs have a nasty way of making things not get enough air... A baby bottle brush and a shop vac are usually all that's needed. And to answer your question, yes it is possible to have a small blockage in the vent, develop soot and when the furnace gets hot enough, to burn away the blockage and not have any further soot.

As for the slide, it sounds more like an adjustment problem on the travel switch rather than an actuator problem. If you look at the Lippert website, (or do a search here for the links) you'll find pretty simple and clear instructions on how to adjust the travel on your slide. In fact, I think there's a topic on here complete with pictures and step by step instructions on the adjustment. It's pretty simple, just need to take your time and not "overadjust" on the first few tries, it's better to do it 3 or 4 times than get it too far the other way and lose your reference. I'd guess yours is set to travel in a little too much, and when it contacts the side of your RV, it moves further in, just enough to bind the actuator. When you push against the slide, you free the actuator and it works properly. It doesn't happen all the time, so it's not critically far out of adjustment, rather just needs a slight tweeking.....

If your RV is in warranty and the dealer is going to repair it for free, that's up to you, but if you're paying for the repair, if it were me, I'd wait until it actually breaks (which it probably won't if you adjust the travel switch). But, just to be sure, I'd run through the manual operation instructions and be sure you know how to manually retract the slide, just in case..... It's always better to be prepared rather than caught by suprise !!!!!