Pretty much the same experience we had.

I would add that support is excellent. Ours went bad slightly out of the
guarantee period and they replaced it at no cost.

I filled in the back of ours inside the raised edge with plastic sheet and
then put the hook side of Velcro tape all over the back. Our upholstery
type is such that it will just stick to the side of the cabin wherever we
put it.

--

Roger Long



"Jay Honeck" wrote in message
newsPtqd.410498$wV.201320@attbi_s54...
Many of us cold-weather pilots worry about carbon monoxide in the cabin,
especially in winter. After using the "dot-that-changes
color-on-a-piece-of-cardboard" carbon monoxide detectors for the last 9
years, we decided to look at the new battery-operated detectors.

Last year I made a foray into this field by buying a Wal-Mart home model.
It turned out to be too big for use in the plane, and had an alarm
threshold that was set too high. I got the distinct feeling that we would
be dead long before the alarm ever sounded. After tripping over it for a
few months, it migrated into our home -- and we went back to the
"dot-on-the-cardboard" model.

When www.Aeromedix.com started advertising their "CO Experts" low level
monitor, it sounded like just what we were looking for. While it's still
not tiny, it's much smaller than the home model, and it displays carbon
monoxide levels at a MUCH lower level, without sounding a stupid alarm
until the levels become worrisome.

When they offered it on sale for "only" $99, I bought one. We've been
flying behind it now for several weeks of cool-to-cold weather, and here
are our results:

1. Convenience. I briefly considered mounting it to the ceiling with
double-back tape, but I feared it wouldn't stick for long. Thus, I
settled on mounting it just to the left of the pilot's yoke, on the side
panel. To hold it there I simply installed a longer screw in the side
upholstery, and "hung" the unit from the screw. (It has a screw-mount
hole on the backside.) This has proven satisfactory -- it's a nice
looking unit, it's not in the way, and it's clearly visible for both pilot
and copilot. It can also be easily removed in the summer, if desired.
(Which we won't do, for reasons listed below.)
Rating: Fair. (I'd rather it was smaller.)

2. Usability. Controls on the unit -- which runs on a single 9 volt
battery -- consist of a digital LCD readout, and a test/reset button.
Before each flight we push the test button, which sounds an alarm tone and
runs the unit through a diagnostic routine. It's simple, easy, and
requires nothing more than a single push of a single button to assure that
it's working.
Rating: Excellent.

3. Sensitivity. On take off, at high angles of attack, it's not unusual
to smell exhaust in our plane. The 235 is capable of some fairly
impressive climb rates, especially when lightly loaded, and I like to get
high as quickly as possible -- so suffice it to say that we routinely
smell exhaust during the climbout.

I've always wondered how much CO we were getting in the cabin when this
happened, but the "dots-on-the-cardboard" never registered anything.

The CO Expert immediately came to life during climbout, showing a read-out
of from 10 to 17 parts per million. (The FAA minimum is 50, so this is
not alarming.) Once we leveled out, the smell went away, and the CO
Expert went blank. The unit updates every SIX seconds, so it reacts very
quickly to changes, and it appears to be every bit as sensitive as they
say it is.
Rating: Good.

4. Results. In cruise flight, we register no CO in the cabin.
Surprisingly, our highest readouts have been observed upon throttling back
to enter the pattern -- with the heater OFF. Levels as high as 34 ppm
have been observed (still well below the FAA threshold of 50 ppm) on
downwind in this flight regime, which surprised us.

Again, the angle of attack is different during slow flight, so the exhaust
is apparently being drawn into the fresh air ducts (perhaps up on the
tail, according the Cherokee Pilots Association) during this stage of
flight.

Interestingly, turning the heater on (and thus pressurizing the cabin a
bit) caused CO levels to drop back to zero. Nice to know our heat
exchanger is evidently not cracked!

5. Conclusion. The unit works as advertised, and has given us confidence
that our aircraft is safe. We are confident that the CO monitor will give
us ample warning of high CO levels in the cabin should a heat exchanger
crack, or some other leakage develop.

Since the highest levels of CO have been observed with the heater off,
it's easy to see that carbon monoxide isn't just a cold-weather issue. I
think, however, that you won't see potentially dangerous levels of CO in
the cabin unless you're getting it through a bad heat exchanger, or a scat
tubing leak -- but since the unit takes up so little space we'll probably
just leave it in the plane all the time.

Overall Rating: Excellent. I'd buy it again.

See it at http://makeashorterlink.com/?E3E8243E9
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"