You need to provide more ...

You need to provide more information for a sensible answer to your question.

Are you wanting to know the maximum feed-water temperature for membranes?

Note that selection of the correct grade of stainless steel to avoid pitting &/or crevice corrosion is also temperature dependant.

And then there is the maximum temperatures for the motors, power systems and electronics.

If you struggle with these basic parameters maybe you need an expert. DM me :)