The past week my Kenmore refrigerator freezer has been running about 15
over 0. It used to be 0 or a bit less on the Walmart freezer thermo. I
tried another Walmart thermo that measures both refrig and freezer. Same
reading. Called extended warranty service guy. His (expensive?) thermo
read -5. He says freezer ok, my thermos bad. I had no grounds to argue
with him about it.
So my question is, where can I get an accurate thermo a service guy will
believe? Brand name? Source? Service guy says to buy from refig supplies
co - he also says the only one in my city only sells to dealers, service
I also found out a previous service guy was wrong, my refrig does have
cooling coils. They are in back at bottom-rear (not under) of refrig. He
and I tried to pull refrig away from wall in it's little walled-off area
but were unsuccessful. Any suggestions on how I (79 yrs old) can move it
out to get at coils to clean them? Service guy suggested a leaf blower
blowing under frig - says it will clear off rear coils. ???
Not sure what that is, but when I measured lab equipment I had access to a
few of my choice instruments. Radio shack $15 thermistor probe, fluke and
triplet thermocouple probes. Fluke IR thermometer, as well as HF near field
IR thermometer. Large mercury thermometer, I only used as a comparison.
Sometimes probes have to be right on top of each other, and stabilized, to
get the same readings. Air flows can be deceiving. Even taking a reading of
a beaker of water, needs high circulation to get equal readings. There is
normally a high temperature differential of a still beaker of water.
An IR Thermometer gives instant results and can be used for many other uses
from catalytic converters to bad capacitors in a PC or TV. This was very
handy I when I needed to test for a bad defrost heater. Often available for
less than $20.
Like anything else, one must shop carefully on eBay or Amazon.
My unit seems very accurate when measured against ice and boiling water. I
haven't thought if a standard for high temperature catalytic converters yet.
IR thermometers are notoriously inaccurate.
They measure radiation, not temperature.
Different surfaces have different emissivities. They
give different readings for the same temperature.
More expensive ones have adjustments for emissivity,
you just have to know the exact number for that exact
Another little-appreciated fact is that cheap ones have
field of view. Unless the item fills the field of view,
you can't count on the numbers.
If you wanna measure the temperature in the fridge for cheap,
go get a liquid thermometer. Those graduated on the glass
are likely more accurate than those that can move
against a calibrated holder.
It's really, really hard to believe that your thermometer suddenly failed
unless you whacked it. Yours reads 15 deg and his reads -5? That's 20 deg.
Something is most strange.
Take your thermometer out of the fridge and park it near a room thermometer
for half an hour. Is it 20 deg off?
Any cheap fridge/freezor thermometer should be NSF intl certified. That
means it's food safe and fairly accurate.
Ok, let's move the fridge. It's in an alcove and is glued down by years
of kitchen crud. Turn off the fridge using the temp control inside the
fridge. With the fridge door open look for and remove the bottom trim panel,
often look like vents. With the trim off and the fridge door closed you
should see the 2 front supports they should look like big bolts with rubber
feet. Get a pry bar and a fulcrum. Find a spot near a foot and on the
metal frame of the fridge. Pry there. We want to lift the fridge. Now do the
other foot. This should "unglue" the front feet.
Now carefully push the top of the fridge into the alcove. Then out. We
want to rock the fridge to free up the 2 back feet. When all of the feet are
free you should be able to rock the fridge from side to side and "walk" it
out of the alcove.
Now, unplug the fridge and vacuum the coils under and in back of the
fridge. Get a mop and swab out the alcove floor.
Plug the fridge back in. Walk the fridge back into the alcove. Open the
door and reattach the bottom trim panel. Set the temp control and close the
He may have been reading the C scale instead of the F scale. the -5 C is
about 23 F.
To check the thermometer you can get a glass and put some ice and water in
it. Stir it for a while and put in the thermometer. It should show 32 deg
F or 0 deg C. Just don't have the thermometer on the ice ore side of the
glass, but in the water.
If your old thermometer changed that much and another one agrees with it,
looks like the service man may be wrong. Next time get him to try the ice
Also, refrigerator & freezer temps continuously 'bounce' up and down all
the time caused compressor cycling, defrost cycles, and door opening events.
It's the 'average' temperature that's important.
For the refrigerator side, put your thermometer in a glass of water; one
where you can read it while still submerged. It's amazing how quickly
some thermometers can react to room temperature air if pulled out for
reading. Give it a day to normalize, then take and average multiple
readings over a few days.
Same dance with the freezer, but sandwich the thermometer between
something like bags of frozen vegetables, and read with the sensing bulb
For the record, I've had pretty good luck with those bi-metallic analog
refrigerator/freezer thermometers. Their 'capsule' isn't vented, so they
retain an accurate reading for a short period. They can also be
quickly/easily read in place... and I'm now in the habit of checking
them every door opening
I've heard the best temps for maximizing food storage time with minimal
energy use is 40°F in the refrigerator, and 0°F for the freezer.
As I recall, most if not all of the above is in my refrigerator owners
manual... check yours, it's likely there as well.
Looks like you tried two thermometers good show. Where it was placed and
time of day might alter readings.
If you want to be safe, use one thermometer that measures closely to one or
two others. I also often use an IR thermometer to verify another reading.
Thermometers can drift off, or be off. Just know what Is what.
I don't have access to it anymore, but I used to also use a data logger to
track 24 hours.
I've found mercury thermometers are all over the place at freezer
temperatures. 10C errors are easy to have. I put the unkown
thermometer in a known good freezer running at -18C and mark the
mercury level with a marker pen, then use it to check my unknown
Even allegedly accurate thermocouple thermometers on a digital
multimeter can be all over the place at -18C.
Having said that I do have some cheap mercury thermometers that do
actually read correctly at -18C. Otoh I have two quite expensive
refrigerator mercury thermometers that read fine at refrigerator
temperatures, but are both quite wrong at freezer temperatures.
My experience is that it isn't easy to read freezer temperatures
accurately. Even allergedly identical mercury thermometers can differ
by 5C. (I've tried 30 or 40 mercury thermometers out btw.) Ditto
bimetal strip thermometers.
Yeah, I know. It surprised me too!
Btw it makes quite a difference to freezer running cost if it is
running too cold. 10C too cold is the same as making it 10C hotter
ambient temperature. It can boost the daily running cost by 50%.
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