Hansgrohe shower system.....

I recently purchased a home that has a Hansgrohe shower system in the master....it consists of a rain shower head coming from the ceiling...a hand held shower...a shower head coming out of the wall and three body spray heads......the control valve has a red button on it and I believe it is a eco max thermostatic valve..not sure though....in any case the water pressure out of any of the four selections above is not very good, but when I grab the handle to adjust the temp and move it side to side...not turning it but just moving it to the side as it seems a little loose.....the pressure increases drastically......regardless of where the temp is set....which would lead me to believe that it is a problem in the valve itself.......Is this a right assumption? I am going to call a plumber to come and look at it...but thought some one here might be able to shed some light on this.....thanx...Rick

After looking at the fixture again....it is indeed a Delta Select.....although I think it is still a thermostatic valve.....I am attaching a photo of it....

Can anyone identify what model this is....I have brought the valve to my local plumbing store...and they cannot....I know it is a Delta Select......

I believe it is a :

Delta Select T66460-BB Total Escape Metal Lever Thermostatic Trim, Polished Brass

http://www.**************.com/Prod/...hermostatic-Trim-Polished-Brass/96065/Cat/905

Delta select

The valve has filters that probably need to be cleaned. Ask Delta for a link to their instruction manual so you can service the unit. You may need a new thermostatic cartridge because it sounds like it may be sticking.