Hi all,

I have an outdoor natural gas central heating unit (which also has a built-in AC). On the side of this large box-like unit is a small vent that outputs hot air/gasses. The odor of these gasses has a VERY strong "chemically" smell. Is this normal, or might there be excessive unburnt natural gas mixing with the normal heater vent exhaust? And can this be dangerous?

Thank you!