Wafers don't last forever and yours might be due for a replacement, but if the wafer is working properly these are pretty easy to regulate. Turn the screw on the top clockwise to lower the temp and counterclockwise to raise the temp. Snug down the wing nut and allow the thermostat to cycle a few times and stabilize the temperature to see if further adjustment is needed.
PM me with your email address and I'll send you a copy of the instructions.
db
PM me with your email address and I'll send you a copy of the instructions.
db