It is the site policy, which I support, to ask and answer questions in the public forum. Usually it is the quickest way to get an answer. It also protects you from those more eager, than able to help. If somebody posts a bad answer, somebody else will soon see it and say so.

From a PM:
''labman, sorry for contacting you this way, but i feel it to be somewhat of an urgent matter. i found you through a post that you answered about a furnace fan not shutting off.

i'm having the same problem in a new house that we just bought over the weekend. thing is, i don't know have any "electrical know how" on how to personally correct the situation. i've put calls into get it serviced, but nothing is going to get done for a few days.

my question is how concerned should i be that this fan is continually blowing for hours and hours on end. and what if it continues to stay on throughout the night? it started around 7:30am PST this morning and has been on for nearly 6 hours now.

is it safe for my wife and newborn to be in the house right now?

any answer would be appreciated. thank you in advance.''

As I said in my brief PM, it is safe to operate the furnace in that condition. The next step is to look at the thermostat. Most of them have a fan on/auto switch. If the switch is in the on position, turning it to auto will solve the problem. Continuos fan is an option you can select. There is a discussion of it in the sticky at the top of the Heating forum. There is other good information there too. Northern Heat has done a fine job on his sticky.

If turning the switch to auto doesn't fix the problem, likely the blower relay is sticking. Unfortunately you may have to pay a technician $400 to replace the control board to fix it. This will be worth calling to the attention of the seller. At possession, major systems including the furnace are expected to be functioning.