On 26/11/2012 4:30 PM, nestork wrote:
You should be aware that ovens purchased within the last 20 years no
longer use thermostats to control their temperature.

Nowadays, they use a thermistor in the oven. The resistance of the
thermistor varies very precisely with temperature, and the circuit board
in the oven console measures that resistance and determines the
corresponding temperature in the oven.

It's possible that the thermistor is gone and you need a new one. If I
recall correctly, at room temperature, the thermistor should have a
resistance of 1000 ohms. Maybe take the thermistor out of your stove
(it looks kinda like an oil filled capillary bulb, but shorter) and take
it down to your local Frigidaire factory authorized service depot and
have them check it for you. There won't be any charge for that.

While it's possible the thermistor is shot, it's probably more likely
that the someone has programmed the oven to operate at a higher
temperature. You see, one of the most common complaints customers have
is that their new stove "just doesn't bake (or broil) like the old one
did", and the usual cause of that is that the old stove had an oil
filled thermostat bulb, and that thermostat was out of whack by 50 or 60
degrees.

So, to address those complaints, programmable ovens can be set so that
they will automatically add or subtract a certain number of degrees to
the temperature you set the stove at so that it will mimic the behaviour
of the customer's old stove. So, if you're used to baking cookies at
350 degrees on an old stove whose thermostat was so far out of whack
that when you set it at 350, the actual oven temperature would only be
300, then you can program your new stove to subtract 50 degrees from
whatever temperature you set. So, when you set the stove to 350, it'll
actually bake the cookies at 300, just like the old stove did.

I suspect that either the previous home owner or someone just mucking
about with the stove got into the programming menu and changed the oven
offset temperature.

I agree with the previous post to go to Jeff's website at
ApplianceAid.com and get his input on it. Jeff's an appliance repair
technician, so he's probably be very familiar with Frigidaire stoves.

Also, you should know that the temperature within the oven will vary by
a good 25 degrees from the front to the back and from the bottom to the
top. You're always going to get some variation between the temperature
reading of an oven thermometer that stays inside the oven during baking
if for no other reason than the thermometer is located at a different
location than the thermistor. However, if you're using an oven
thermometer that uses a clip that you clip to the oven rack, clip i
the thermistor instead. That way your oven thermometer will be at the
same location as the thermistor, and both your thermometer and the oven
digital read out should be within a degree or two of each other.
emperature



I checked the accuracy of the oven temperature of a new stove when I
purchased it a few years ago, using a calibrated thermocouple readout
with an accuracy of +/- 2°F. I placed the probe in the centre of the
oven and monitored the temperature to see the variability at set points
of between 250 and 450°F. I was quite surprised at the huge cycle swings
in the oven's temperature.

I found the controller cycled on and off within +/- 25°F of the set
point, with an additional lag of 25°F in the response of the elements,
for at total cycle range of +/- 50°F, over a total cycle time of
something like 20 or 25 minutes. Although it was difficult to measure
with the big cycles, I estimated the average temperature would have been
close to the set point. I wish I would have checked the oven in
convection mode to see how much it affected the cycle profile. If I do
this test again, I'll use a less responsive oven thermometer, as long as
I check its accuracy first. Ovens have their control sensors immersed in
an oil bulb to temper these swings and somewhat mimic the response of
food cooking.

I suspect this is typical performance for an electric range and it works
well for me as my food typically cooks in the expected time.