# How does Boudouard reaction influence the temperature?

I've a question that is giving me a lot of troubles: I'm depositing and gasifying Carbon by varying a flow rate of $\ce{CO}$ and $\ce{CO2}$ and by using the Boudouard reaction ($\ce{2CO -> C + CO}$). When I'm depositing carbon, I notice from my Temperature sensor at the outlet of the test-house, an increase of temperature (and I associate this both to the exothermic nature of the reaction but also to the fact that part of $\ce{CO}$ that didn't react is then burned into $\ce{CO2}$ in a furnace that surrounds my test-house. The problem is that I have a Temperature sensor also at the inlet and this shows a decrease of T when I deposit carbon and an increase when I am gasifying it (which is the contrary of what is expected). Do you know any possible reason for this strange behavior?

• drawing of this setup? I dont't get it. – Karl Sep 20 '18 at 8:04