The black exhaust Black seems to be a depressing color. The reason must be rich mixture. That is to say, the amalgamation of gas in cylinder component is at night normal level. The incomplete combustion gas inside combustion chamber result in the carbon particle exhausted with the waste gas. Failure is likely to come from the following reason: Some may help some renowned tools like Tarot cards, crystal balls, runes, tea leaves, etc., while some would rather investigate the cases with all the bare hands. To these experts, the info they perceive arrive directly at mind, not through another tool. Via Psychic vision or clairvoyance, the so-called Psychic investigators try the ability of giving predictions and interpretations depending on whatever they sense beyond the physical contexts. A tighter built home means less outside air infiltrating in the home, which means less oxygen to use for combustion within the furnace. As the furnace burns fuel and oxygen for combustion, it "eats up" surrounding air, which has to be "made up" with fresh air. If air cannot type in the home as easily anymore, this can cause serious issues. As the surrounding air is utilized for combustion, rather than substituted with oxygen, a negative pressure inside the space can happen. This could create combustion problems for the furnace, plus burn up fresh air for anybody inside the home.