I've looked around the archives, and have a pretty good idea of the basics of my problem, but had questions about specific questions to ask our contractor and what my expectations should be.
My wife and I live in the metro DC area, and our house is a one-story ranch house. We replaced the central A/C unit and furnace in Sept. 04. The old furnace was fine (no condensation problems and heated well), but the contractor convinced us it would be cost-effective to replace it at the same time as the A/C since it was almost 20 years old.
We now have a new 80% efficient furnace and have been having condensation problems ever since we turned on the heat in the late fall. The condensation is a light, oily substance the color of light machine oil or 3-in-1 oil and is driping back down the flue and onto the basement floor. The condensation is so bad that it also discolored the drywall in a closet that is next to the chimney.
The contractor came back once, looked up the chimney and said, "Yep. Condensation." He told me to go into the attic and wrap the transite vent with insulation, and I wrapped fireproof insulation around the transite vent from the attic floor on up. No change. The condensation is just as bad.
Before I call this guy back, I want to make sure I ask the right questions and have him run the right tests so he doesn't just leave after 2 minutes like last time.
Should this contractor have replaced or recommend replacing the transite vent originally? (Unlike some jurisdictions, I don't think it's required under our county code.)
What tests should I ask this guy to check when he comes back? What are possible fixes he might (or should) recommend? Also, who should pay for this fix?
After coughing up almost 6 grand I don't think the fix should come out of my pocket because the problem didn't even exist until he did the work.