Why is My Furnace Blowing Cold Air? Causes & Easy Fixes | Air Now
Modern Furnaces Can Tell You What’s Wrong Most furnaces built in the last 15–20 years include diagnostic technology that helps identify problems. On the front panel of your furnace, you’ll usually find a small sight glass with a flashing light: red, green, or amber. If your furnace detects a problem, it will flash a code …










