I recently had a hot water heater and thermal expansion tank installed by a licensed plumber. I was not present at the install. But afterward I noticed that the thermal expansion tank was installed on the hot water side of the water tank.

Will the expansion tank still work (reduce water pressure from thermal expansion) when installed on the hot water line? And if so, will it cause any problems having it installed this way?

Thank you for any advice you can give.
-Bob