Is there a device to test CO sensors?
Garage in multi story building has CO sensors to turn on the exhaust fans. We would like to test at what level the contacts close.
Old snipes don't die they just loose their steam
First, I would consult the manufacturer of the CO detectors to determine the proper operation/setpoint.
Unless the manufacturer says otherwise, you should be able to blow smoke (cigar, cigarette) on the sensor to make it trip.
Lots of manufacturers make CO meters. For example Fluke has a meter, M/# CO-220, or a probe that connects to your multimeter M/# CO-210.
There are professional test kits available, but, do you want to expose yourself to that liability?
If I had any doubts that CO detectors were working properly I would have them calibrated or replace them.
I use the Fluke co meter and you can get calibration kit for the meter.
What will your legacy be ??
Our CO alarms go off at work all the time and no one does anything but silence the alarm. I work with really smart people.