Hydrogenated diamond (HD) gas sensors feature an integrator-like response which occurs at room temperature and which is mediated by a thin layer of adsorbed water on the HD surface. In the present work a HD gas sensor had been exposed to randomly varying acid vapour concentrations to assess its potential in a practical gas monitoring situation. Our results demonstrate that the time-differentiated sensor output signal yields a detailed temporal image of the random vapour pulses with a time resolution in the order of one second. In contrast, the sensor signal itself provides a measure of the total vapour concentration that had been interacting with the HD sensor surface up to the point of sensor interrogation. Large accumulated vapour concentrations lead to sensor saturation. It is further demonstrated that saturated HD sensors can be repeatedly reset into a reproducible initial condition, simply by replacing the contaminated water adsorbate layer by a fresh one.