Why is there a room temperature oscillation?

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I am modeling an old air handler with a constant fan. I am analyzing the hourly data for the simulated year, and I’m seeing a weird oscillation in room temperature at every hour for the whole year and I don’t know why. I don't think the temperature should be spiking this high, especially up to 130F. Does anyone have ideas as to why this is happening? The attached images are for September and January, where September is the peak heating month. Also the HVAC setup is attached. The steam coil and cooling coil both on district. Temperature is in Celsius. Why is the temperature spiking up so high and every hour? September January