Hi all. Am hoping I could get some help in troubleshooting an old freezer.
Model: F1073, upright manual defrost
Year: early 1980s
Problem: Excessive frost buildup requiring weekly defrost
Main areas of frost build-up are at the ceiling and the underside of the
top shelf, along with the process tube (tube1 is the segment beneath the
top shelf, tube2 is the segment beneath the middle shelf).
Note that there is no frost buildup under the middle (or the bottom) shelf.
I have no experience in appliance repair, but am a technical sort, and have
a multimeter handy. Have borrowed a bunch of books from the library on
appliance repair, but none give any specific steps on troubleshooting a
freezer with excessive frost buildup. But they do give some general guide
on things to look for.
. Put a thermometer (in cup of veggie oil) in freezer to measure temp.
Temp seems to be at -10 to -15 degree F, which according to the books is
probably too cold (they cite a range of -10 to 10 degree F). The
temperature control knob is already set at the minimum setting without
shutting it off (there is a click before getting to the off position, and
the motor does turn off when I turn the knob to the off position).
. Visual inspection of the surrounding seals seems OK, other than this
I tried that particular spot with the dollar bill test (i.e. put a dollar
bill in between and see if it can slide in/out easily), and the seal seems
to hold up.
Some books talk about a thermostat, but apparently that's only for
auto-defrost models. One book does show a thermostat element for manual
models that's underneath one of the shelves, but I didn't find anything
like that. My assumption is that this manual model doesn't have one.
My next step is to pull the temp control housing and check for resistance
at the highest (little to no resistance) and lowest (high resistance)
setting. My hope is that it is the culprit, and I can just replace this
The books also recommend cleaning out the condenser coil (at the back of
the freezer, not the bottom). I don't see any excessive dust build-up on
Aside from the temp control, and more thorough checking of the seals, I'm
not sure what other areas to try for this particular issue. I hope that
someone here can provide more advice for me. Thank you in advance.