I wondered if my 20 year old Hotpoint freezer was on continuous freeze - the compressor seemed to be running continually. Dodgy thermostat? Having checked online for a replacement thermostat, I was surprised to see that the replacement part (Ranco K54 range)) had a control shaft. My freezer doesn't have a temperature control knob. Err.. yes it does - it's at the back near the compressor with no knob and no markings. Does anyone know how this should be set? I have never touched it in 20 years until just now and I can't find the handbook.