It depends from year to year.
Only the low air returns have dampers, and they should be open in winter, so they can suck in the lower cold air (cold air sinks), and in summer the dampers should be closed, so the high air returns suck the hot air near the ceiling (hot air raises)
The air intake is positioned so it can pull fresh air from the grille. This opening should be well below the location of the actual air filter so water should not be a big issue, but there are fresh air kits available to get the intake even higher.
it is a mild acid so you should be safe
Nobody seems to know the answer, so type in this question: What is in gas that pollute the air? That should help answer your question!!!
Transmission fluid should never be in your air intake if so take it to get fixed
have an object surrounded by the air at a lower temperature that the dewpoint so that the moisture would condense on the surface.
They have air trapped inside so they should float.
At first it should put out hot air for a few moments but then it should start to cool down the air. If it does not do so, it's time to get it serviced. It may have leaked out all it's freon over the winter.
Toward the direction of the air flow. In other words the air is being drawn into the furnace so the arrow should point at the furnace.
so the air can get in!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! thank you for doing business
It flies in the air and takes you places...no offense but its very obvious... so you should know that..