I have a hot water boiler to heat my house. I currently am getting heat upstairs but not on the main floor.

Sounds like you may have a bad circulator pump. Heat will naturally rise to the highest point on gravity. If the circulator is not working, the upper floor will heat up and the thermostat which is on the lower floor will keep the boiler running because there is no heat on the lower level to satisfy the thermostat..

Hi Kkoz13:

How many zones... or how many thermostats in the home? How old is the boiler and are there any shutoffs above and below the circulator?

Issue could be either a faulty thermostat/wiring (if you have separate zones) or a faulty circulator as Bentzle suggested.

Answer the questions and we can discuss further.

MARK