You are correct.  The heating element on an oven that is 4-5 years old 
should not be "going out" ...if it has not been artificially corroded.  
Solvents, oxidizers, paraffin, etc. that has been spilled or dripped 
onto the heating element will most certainly harm it.  Also, you did not 
mention what temperature you are routinely using.  From what I see on 
the HistNet, most folks run anywhere from 50 degree C to 70 degree C.  
The higher the temp, the shorter the life of the element... but even at 
70 degrees, an oven heating element should last for many years.  This 
depends on the "oven".  What is the temperature range, as specified in 
your operator's manual for your oven?.  Most "ovens" are Room Temp. to 
200 to 300 degrees C.  Check your "oven" to make sure that you are not 
actually using an "Incubator"  Standard Incubators have a temperature 
range of Room temp to 65-70 degrees.  If in fact you have an "incubator" 
and are running at 65 degrees, you are almost at the max of the 
temperature range set for that heating element.  It will therefore burn 
out much quicker.  Oven  heating elements (200-300 degrees) are made of 
sterner stuff than Incubator elements.

Another thing to check is if it is, in fact, the heating element that is 
going out.  It could be an electrical problem elsewhere in the unit.... 
the thermostat as example.

In my years of experience, I have not seen a major shelf- life 
difference between those who leave their ovens 'ON' 24/7 and those who 
turn them off at the end of each day.

Just a few tips in the wind...

~ Ford

Ford M. Royer, MT(ASCP)
Midwest Science & Biocenter
Minneapolis, MN
800-745-4869


Paula Lucas wrote:

>If someone could offer an opinion or if any one has experienced this type of
>situation, I would appreciate the feedback:
>
>We have an oven that is about 4 to 5 years old, which we use to dry our
>histology slides.  The heating element is going out already and my concern
>is that it's relatively new for having this problem.
>
>We turn the oven off before we leave for the day and then turn it back on
>the following morning.
>
>I'm wondering if turning on/off would cause problems or it really doesn't
>matter.
>
>Do you keep your ovens on overnight or off?
>
>Thanks in advance.  It's greatly appreciated.
>
>Paula
>Bio-Path Medical Group
>
>
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>Histonet mailing list
>Histonet@lists.utsouthwestern.edu
>http://lists.utsouthwestern.edu/mailman/listinfo/histonet
>
>
>  
>


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