My heating system is not providing even distribution of heat. Some areas are warm and others are cold. All registers are open and furnace is cycling properly.
Any idea?

THANKS!

You might want to check the duct work to insure you have no broken or separated ducts, are you getting air out of the ducts in the rooms not heating? Is your duct insulated ?If your duct is insulated on the inside some times the insulation will dislodge and block airflow.
Good luck, Mike

A lot of older duct systems are all 6" supply lines to every room. Think of your duct system as a sprinkler system and adjust the vent dampers to allow more air where you need it and less were you don't. In your mind put smoke it the air and think about the path that it is going to take to get back to the return and pass the thermostat. The further away the room the more air it may need. Bathrooms will need less flow. You need to remember that you should not shut them all they way, but they all should have a slight damper to them(even in the coldest rooms).