you have shown the valve but not what needs to change color, the blue?
the blue is done with gradients, which is quite a bit of work to change, instead you could use a filter
its also a bit of searching for the correct filter but it will be easier than changing all the gradients.
4 and 5 are the ones in blue
Note it doesnt seem like the designer can handle filters so you should test out the correct value in the browser. with the inspector (no idea of the app can handle it)