The thermostat is located near the bottom of
the support box. The thermostat is connected by two or three wires.
Label the wire placement before disconnecting them. Remove the
thermostat by loosening the clamp, by pushing back the retainer
clips, or by removing the retaining screws.
Test the thermostat for continuity
using a multitester
set to the ohms setting X1. Start by testing the thermostat when
it has come up to room temperature (about 20 minutes after removing
it from the freezer).
If the thermostat has two wires
touch one probe to each wire. You should get a reading of infinity.
Chill the thermostat in the freezer for about twenty minutes and
retest. This time you should get a reading of zero (continuity).
If the thermostat has three wires,
number them 1, 2 and 3. Test combinations 1 & 2, 1 & 3
and 2 & 3 and write down the results. Two of the combinations
should yield a reading of infinity and one should yield a reading
of zero. Now chill the thermostat in the freezer for about twenty
minutes and retest. The combination that had a zero reading before,
should now have a reading of infinity. One of the two other combinations
should now yield a zero reading.
If the thermostat fails this test,
it should be replaced.
