In version 1.16.1, I built thermal boilers and industrial turbines. I wanted to bring the steam from the thermal boiler into the turbine, but I found that it was not possible to use mechanical pipes and that the turbine valve did not recognize it. I switched to a pressurized pipe, but I couldn't transfer steam. What's the reason?

Steam uses a pressurized tube not mechanical pipes, you also probably haven't changed the boiler valve's mode to output from input.

So how to change the output input mode of the boiler valve?

Using a configurator