"ap" wrote...
Hello,
After shopping around much, purchased a nighthawk digital for $33 from
wal-mart.
These are expensive and I'm wondering if the best placement would
be high in the hallway near the bedrooms. There are 3 bedrooms that are
occupied.

by the way...the inside of a heat exchanger is under positive pressure
from the blower...

if it should crack, air would blow out of it, it would not pull CO in
....

but bad stuff can happen and a CO detector is a very good idea...

Mark