Thanks for the info...I called one of the NCI contractor from the website near my area. Here's what he said. NCI??? What is that? oh man! He didn't even know what a NCI 3000 was? So, I thought maybe I called the wrong #. Nope, the guy said they are HVAC store. I had to explain to him what a NCI was.
He has been in business for 11 years but didn't know he was NCI contractor. Go figure..
Outdoors levels for CO are not allowed to exceed 35ppm.
OSHA levels in factories are not allowed to exceed 50ppm.
Parking garages are not allowed to be over 35ppm.
UL 2034 CO detectors allow 69ppm indefinitely in your home and never have to go off. CO is lighter than air. Most plugs are near the floor and may not see the CO. Alarms need to be eye level-no higher/no lower.