I've got a taco 1/2" mixing valve on my radiant floor, and about 16" down the line I have a temp gauge. Both of them are 2 yrs old. I noticed the floor felt too warm a few weeks ago, and went and checked the temp.. 125deg. I sorta guessed that backing the threaded valve out would increase temp, and threading it further in would decrease. So I threaded it all the way in and checked it the next day. No temp change. I threaded it all the way out until water dripped out, then backed off a bit, and checked it again the next day. Still no temp change. What gives?