1. When the water is running there is water leaking from behind the handle

This is a common maintenance occurrence for any packed valve of any brand or manufacture.  It is overcome by simply tightening the packing nut with a crescent wrench.  This will force the packing tighter around the stem to eliminate leakage.

Occasionally, the packing will need to be replaced if the packing nut has been repeatedly tightened.

The parts required for this is a C-134KT-803 Packing Kit