Getting rid of temperature and enthalpy peaks

Hi,

I have a model of steam from an evaporator getting inside a piston:

However I get weird results as you can see:

The specific enthalpy of the steam inside the chamber is bigger than the one leaving the evaporator, whereas there is no heat transfer in between (the one on the mechanical converter isn't activated).

How is that possible and how can I get rid of this weird effect ?

I tried to put volumes between but the h_I of the chamber always has a different value than it's inlet. This has also for consequences to create huge temperature spikes up to 220 °C for a fresh steam at 165 °C which doesn't make any sense.

Thank you very much!

[Joris Naudin]

Here's the temperature with enthalpy: