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could elements effect firing temp?

updated fri 14 jan 00

 

David M. Jolley on mon 10 jan 00

I have an older Duncan GK 1020 Electric kiln. I have recently replaced
the switches, which I bought from Paragon Industries, (who bought out
Duncan) and the elements, which I purchased from Euclid Elements Co.
Now, my problem is this...My usual fire time has been 10 hours for a
cone fix. But since replacing these parts, I have not reached the
correct fire temperature even after 15 hours. The switches seem to be
installed correctly, because they both read 15 amps. to give the kiln
the required 30 amps. The resistence is correct and also the correct
power into the house. So my question is this...When you fire a kiln for
15 hours and it does not reach the correct temp., what could be the
problem? What should I be looking for? The people at Euclid insist
that the elements cannot be causing this as do the people from Paragon.
But the kiln worked perfectly before these installations.

David Hewitt on thu 13 jan 00

David,
While I am not familiar with Duncan Kilns ( my electric kiln is a
Chromartie with two elements, each separately controlled with a
proportional regulator) and so am not sure what switches you have
changed, but it seems unlikely that these are the cause of your problem.
How many elements do you have? Could one of them have failed or not be
properly connected as a result of changing the switches?
Do you have a meter on the kiln or can you turn everything off except
the kiln and see, with all elements supposedly on, if the watts being
taken is correct. Better still if you can get a tong tester and measure
the current being taken by each element when turned on.
Elements do 'age' with use and so take less current and hence give out
less heat (watts), but this is a slow process and hence does not fit
with the sudden change that you are experiencing.
My two controls are a meter on the kiln and a tong tester.
The meter instantly tells me by the speed of rotation in one or two
elements are taking current and hence if one has failed for any reason -
element burn out or faulty connection.
The tong tester for taking current readings on each element enables me
to check new elements as being correct and for monitoring the 'ageing'
or fall off in current. Firing time is also a very good guide of this
'ageing'.
Trust that you have anyhow found the cause of your problem.
David

In message , David M. Jolley writes
>----------------------------Original message----------------------------
>I have an older Duncan GK 1020 Electric kiln. I have recently replaced
>the switches, which I bought from Paragon Industries, (who bought out
>Duncan) and the elements, which I purchased from Euclid Elements Co.
>Now, my problem is this...My usual fire time has been 10 hours for a
>cone fix. But since replacing these parts, I have not reached the
>correct fire temperature even after 15 hours. The switches seem to be
>installed correctly, because they both read 15 amps. to give the kiln
>the required 30 amps. The resistence is correct and also the correct
>power into the house. So my question is this...When you fire a kiln for
>15 hours and it does not reach the correct temp., what could be the
>problem? What should I be looking for? The people at Euclid insist
>that the elements cannot be causing this as do the people from Paragon.
>But the kiln worked perfectly before these installations.
>

--
David Hewitt
David Hewitt Pottery ,
7 Fairfield Road, Caerleon, Newport,
South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
FAX:- +44 (0) 870 1617274
Own Web site http://www.dhpot.demon.co.uk
IMC Web site http://digitalfire.com/education/people/hewitt.htm