The fire alarm system at my house is handled entirely by our property manager as it is semi-attached housing, so we have a centralised fire panel for all the houses. We only have two hockey puck shaped sensors on the ceiling of our house, one on each floor, and that's it in terms of safety sensors. We have gas fired appliances and people in my family and the neighbours I've talked to all seem to assume that they are combo detectors that do smoke, CO and natural gas all in one, but I'm honestly really skeptical. Looking at the outside of the detector it has no text or markings that suggest it does anything other than smoke (though I haven't taken it off the ceiling and looked at the actual label yet since we technically don't own it), and looking online the actual confirmed three in one detectors all look quite different from ours with more indicator lights to tell you what's been detected. I have also watched the fire monitoring company test the detectors, and all they do is aim one spray can at it to trigger it, when in my mind shouldn't they test it three times, one for each function? Starting to get really worried that we only have smoke detection despite having gas appliances, so I want to test it myself. If it really doesn't detect the other two I plan to buy separate detectors (and also alert my neighbours/write to the strata council), but if it does then it would be a waste so I want to be sure.

Is there an easy way for me to independently test the CO and gas detection functionality of a combo detector at home? I'm certain we have smoke detection (because it's gone off due to smoke) so no need to test that. I want to exclude smoke from my testing so it doesn't give me a false sense of security for the other two, but I obviously also don't want to release unsafe amounts of CO or natural gas in my own house. Does anyone know of any effective methods to see what kind of hazard detection our house actually has?