Calling or HVAC experts - with the extreme heat out here on the East coast, the furnace has been working overtime. I've noticed a fairly large pool of water at the base of the furnace and there's been extra water draining from the furnace. Could there be a blockage somewhere? Thank you.

Read this:
http://www.heatpro.us/service/actraps.htm

Yes, there probably is a blockage of the drain.

www.heatpro.us energy businessmen's knowledge

Yes, you really have to find out the MAKE and MODEL to get good answers. There IS more than one machine made.

Check to make sure coil is insulated, and or check condensate drain to see if it is draining, maybe A cracked condensate drain pan