I have a Grohe 34 436 000. Temperature graduations run from 70 ~110. We're running 110 Max temp at the valve inlet. Both stops are fully open. The installation is almost 2 years old now.
Initially, wasn't getting enough hot water and adjusted per owners manual to achieve 110 at max temp. Never did seem to get full cold at any time. During the past six months I began turning the valve 'ON - OFF - ON' and was able to get fully cold water.
Now, regardless of setting, the valve does not have any cold water output. Still plenty of hot but water volume decreases to zero as the temperature control is adjusted lower past 85 degrees.