Really ccs46? No. 24 volts is way out of the range of any device listed at 12V, especially a smoke detector due to their extreme sensitivity. The general rule is +/-10% of the listed voltage is acceptable, but this rule is more commonly used in AC systems. For testing the detector, it will require a compatible panel if it is two wire. If it is four wire, theoretically it can be powered by an external current-limited 12V power supply and connected like a pull station.
For your heat detector, you can test the rate-of-rise device if you are careful. Rate-of-rise detects an increase of heat to a threshold in a certain amount of time, usually around 15F in one minute. If the heat exceeds 135F then you are correct; the fusible link within the detector will melt, the disc will fall out and the detector will be latched permanently into alarm. These can be wired just like a pull station and do not require power, unless it is an intelligent device, which your model is not.