need advice re: heater control

["Tom Borden" <te.borden@xxxxxxxxxxx>]

Replaced my heater control valve back ion November.  Problem is, heater
works too well.  Most times, when I turn heat control knob off my car
still gets heat.
 
Anyone know if this could be because I screwed up the order of the
gaskets on the heater control valve (one gasket is flat, the other
wavy). I could go back in and swap them but I'd like to know ahead of
time, because reinstalling the valve is a pain due to its location.  Or
should I be suspecting something mechanical between the knob on my
dashboard and the valve, e.g., the vent door to interior doesn't close
correctly?
 
Any expertise greatly appreciated.
 
Happy motoring.
 
Tom Borden
1988 528e
149,300

------------------------------