OK, after waking up this morning, I'm having second thoughts now. I
realize if I put the HW heater behind the furnace, it might cause some
servicing problems. Here are some pics of the furnace clearances
( don't mind the mess, its temporary).
http://picasaweb.google.com/mikerock...eat=directlink

The first pic shows where I wanted to put the HW heater, behind the
furnace to the left of the vent, but there is only 26 inches from the
furnace to the foundation wall. The HW heater is 20 inches round. That
might cause problems if I had to service the furnace. Originally I
thought it was fine, but now I realize it might not be.

The second pic shows where I originally wanted to put the HW heater,
to the right of the vent. Putting it there would leave clearance
around the furnace. The HW heater would be diagonally across from the
furnace. And plus I can use the existing flue pipe.

Just curious what everyone else thinks.